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harrykiselev
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Aug 5, 2015
Explain how to open the chat example
ide
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in expo/react-native
Sep 15, 2015
add react-native android command (wip)
chirag04
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Jan 25, 2016
Closed
ekrivopaltsev
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Mar 25, 2016
Some keyboard types does not have buttons correspondent for keyReturnType such as Next, Done. It is observable on IPhone for numeric keyboard types. That prevents traversing forms with "number" input fields and impacts end-user experience. The improvement allows application for adding extra buttons via inputAccessoryView. Because RCTText is not a project exposed to React application calling all methods to add a handler is done using selectors. Here is a code fragment which has an example on how to achieve it: Within application: facebook#1 Create a keyboard Handle KeyboardAccessory keyboardHandler = ^UIView *(UITextField *textField) { ReactTextAdapter *kAdapter = [[ReactTextAdapter alloc] init:textField]; return [kAdapter getInputAccessory]; }; 2. Register an adapter Class clz = NSClassFromString(@"RCTTextField"); SEL selector = NSSelectorFromString(@"registerForKeyboardType:handler:"); if ([clz respondsToSelector:selector]) { [ clz performSelector:selector withObject:[NSNumber numberWithInt:UIKeyboardTypeNumberPad] withObject:keyboardHandler]; } facebook#3 Example of Keyboard Adapter @interface ReactTextAdapter :UIToolbar -(instancetype) init:(UITextField *)textField; -(UIView *)getInputAccessory; @EnD // // ReactTextAdapter.m // KeyboardTest // // Created by Krivopaltsev, Eugene on 3/11/16. // #import "ReactTextAdapter.h" @interface ReactTextAdapter() @Property (nonatomic) UITextField *textField; //@Property (nonatomic)UIToolbar *toolBar; @Property (nonatomic)UIBarButtonItem *flexible; @EnD @implementation ReactTextAdapter -(instancetype) init:(UITextField *)textField { self = [super init]; if (self) { self.textField = textField; [self setBarStyle:UIBarStyleDefault]; self.translatesAutoresizingMaskIntoConstraints = NO; self.flexible = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:nil]; // since there is a next field, add a NEXT button to the picker if (self. textField. returnKeyType == UIReturnKeyNext) { NSString *nextText = @"Next"; UIBarButtonItem *nextButton = [[UIBarButtonItem alloc] initWithTitle:nextText style:UIBarButtonItemStyleDone target:self action:@selector(next)]; self.items = [[NSArray alloc] initWithObjects: self.flexible, nextButton, nil]; }else if (self.textField. returnKeyType == UIReturnKeyContinue) { NSString *continueText = @"Continue"; UIBarButtonItem *contButton = [[UIBarButtonItem alloc] initWithTitle:continueText style:UIBarButtonItemStyleDone target:self action:@selector(next)]; self.items = [[NSArray alloc] initWithObjects: self.flexible, contButton, nil]; } else if (self. textField.returnKeyType == UIReturnKeyDone) { NSString *doneText = @"Done"; UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:doneText style:UIBarButtonItemStyleDone target:self action:@selector(done)]; doneButton.enabled = YES; self.items = [[NSArray alloc] initWithObjects: self.flexible, doneButton, nil]; } } return self; } -(void) done { [self passToReactNative]; [self.textField resignFirstResponder]; } -(void) next { [self passToReactNative]; } -(void) passToReactNative { SEL selector = @selector(textFieldSubmitEditing); if ([self.textField respondsToSelector:selector]) { [self.textField performSelector:selector withObject:nil]; } } -(UIView *)getInputAccessory { return self; }
ekrivopaltsev
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Mar 25, 2016
Some keyboard types does not have buttons correspondent for keyReturnType such as Next, Done. It is observable on IPhone for numeric keyboard types. That prevents traversing forms with "number" input fields and impacts end-user experience. The improvement allows application for adding extra buttons via inputAccessoryView. Because RCTText is not a project exposed to React application calling all methods to add a handler is done using selectors. Here is a code fragment which has an example on how to achieve it: Within application: facebook#1 Create a keyboard Handle KeyboardAccessory keyboardHandler = ^UIView *(UITextField *textField) { ReactTextAdapter *kAdapter = [[ReactTextAdapter alloc] init:textField]; return [kAdapter getInputAccessory]; }; 2. Register an adapter Class clz = NSClassFromString(@"RCTTextField"); SEL selector = NSSelectorFromString(@"registerForKeyboardType:handler:"); if ([clz respondsToSelector:selector]) { [ clz performSelector:selector withObject:[NSNumber numberWithInt:UIKeyboardTypeNumberPad] withObject:keyboardHandler]; } facebook#3 Example of Keyboard Adapter @interface ReactTextAdapter :UIToolbar -(instancetype) init:(UITextField *)textField; -(UIView *)getInputAccessory; @EnD // // ReactTextAdapter.m // KeyboardTest // // Created by Krivopaltsev, Eugene on 3/11/16. // #import "ReactTextAdapter.h" @interface ReactTextAdapter() @Property (nonatomic) UITextField *textField; //@Property (nonatomic)UIToolbar *toolBar; @Property (nonatomic)UIBarButtonItem *flexible; @EnD @implementation ReactTextAdapter -(instancetype) init:(UITextField *)textField { self = [super init]; if (self) { self.textField = textField; [self setBarStyle:UIBarStyleDefault]; self.translatesAutoresizingMaskIntoConstraints = NO; self.flexible = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:nil]; // since there is a next field, add a NEXT button to the picker if (self. textField. returnKeyType == UIReturnKeyNext) { NSString *nextText = @"Next"; UIBarButtonItem *nextButton = [[UIBarButtonItem alloc] initWithTitle:nextText style:UIBarButtonItemStyleDone target:self action:@selector(next)]; self.items = [[NSArray alloc] initWithObjects: self.flexible, nextButton, nil]; }else if (self.textField. returnKeyType == UIReturnKeyContinue) { NSString *continueText = @"Continue"; UIBarButtonItem *contButton = [[UIBarButtonItem alloc] initWithTitle:continueText style:UIBarButtonItemStyleDone target:self action:@selector(next)]; self.items = [[NSArray alloc] initWithObjects: self.flexible, contButton, nil]; } else if (self. textField.returnKeyType == UIReturnKeyDone) { NSString *doneText = @"Done"; UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:doneText style:UIBarButtonItemStyleDone target:self action:@selector(done)]; doneButton.enabled = YES; self.items = [[NSArray alloc] initWithObjects: self.flexible, doneButton, nil]; } } return self; } -(void) done { [self passToReactNative]; [self.textField resignFirstResponder]; } -(void) next { [self passToReactNative]; } -(void) passToReactNative { SEL selector = @selector(textFieldSubmitEditing); if ([self.textField respondsToSelector:selector]) { [self.textField performSelector:selector withObject:nil]; } } -(UIView *)getInputAccessory { return self; }
@robz updated the pull request. |
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RSNara
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May 21, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 21, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 21, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 22, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 22, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 22, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 22, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 22, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 22, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 22, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 23, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new list component is doing synchronous render. That means it makes synchronous dispatches from main thread to the js thread. (To capture the runtime so that it can execute js on the main thread). But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 23, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 23, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 23, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 23, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 23, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 23, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 23, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 23, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 24, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 24, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 24, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 24, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 27, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 28, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 28, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 28, 2025
Summary: # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 28, 2025
Summary: # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 28, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
RSNara
added a commit
to RSNara/react-native
that referenced
this pull request
May 28, 2025
Summary: Pull Request resolved: facebook#51425 # Problem React native's new architecture will allow components to do sync render/events. That means they'll makes synchronous dispatches from main thread to the js thread, to capture the runtime so that they can execute js on the main thread. But, the js thread already as a bunch of synchronous calls to the main thread. So, if any of those js -> ui sync calls happen concurrently with a synchronous render, the application will deadlock. This diff is an attempt to mitigate all those deadlocks. ## Context How js execution from the main thread works: * Main thread puts a block on the js thread, to capture the js runtime. Main thread is put to sleep. * Js thread executes "runtime capture block". The runtime is captured for the main thread. The js thread is put to sleep. * Main thread wakes up, noticing that the runtime is captured. It executes its js code with the captured runtime. Then, it releases the runtime, which wakes up the js thread. Both the main and js thread move on to other tasks. How synchronous js -> main thread calls work: * Js thread puts a ui block on the main queue. * Js thread goes to sleep until that ui block executes on the main thread. ## Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep, waiting for that block to execute. **Result:** The application deadlocks | {F1978009555} | {F1978009612} |  ## Deadlock facebook#2 **JS thread**: execute ui code synchronously: * Js thread schedules a block on the ui thread * Js thread then goes to sleep waiting for that block to execute. **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime to be captured **Result:** The application deadlocks | {F1978009690} | {F1978009701} |  # Changes This diff attempts to fix those deadlocks. How: * In "execute ui code synchronously" (js thread): * Before going to sleep, the js thread schedules the ui work on the main queue, **and** it posts the ui work to "execute js now". * In "execute js now" (main thread): * This diff makes "execute js now" stateful: it keeps a "pending ui block." * Before capturing the runtime, the "execute js now" executes "pending ui work", if it exists. * While sleeping waiting for runtime capture, "execute js now" can wake up, and execute "pending ui work." It goes back to sleep afterwards, waiting for runtime capture. ## Mitigation: Deadlock facebook#1 **Main thread**: execute js now: * Main thread puts a block on the js queue, to capture the runtime. * Main thread then then goes to sleep, waiting for runtime capture **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. The main thread wakes up in "execute js now": * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block." The block, also scheduled on the main thread, noops henceforth. * Main thread goes back to sleep, waiting for runtime capture. * The js thread wakes up, moves on to the next task. **Result:** The runtime is captured by the main thread. | {F1978010383} | {F1978010363} | {F1978010371} | {F1978010379} |  ## Mitigation: Deadlock facebook#2 **JS Thread**: execute ui code synchronously: * Js thread puts its ui block on the ui queue. * ***New***: Js thread also posts that ui block to "execute js now". Main thread was sleeping waiting for runtime to be captured. It now wakes up. * Js thread goes to sleep. **Main thread**: execute js now * Main thread sees that a "pending ui block" is posted. It executes the "pending ui block" immediately. The block, also scheduled on the main thread, noops henceforth. * Js thread wakes up and moves onto the next task. **Result:** Main thread captures the runtime. | {F1978010525} | {F1978010533} | {F1978010542} |  Differential Revision: D74769326
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