[scudo] Support setting default value of ReleaseToOsIntervalMs in config

Author: ChiaHungDuan

compiler-rt/lib/scudo/standalone/allocator_config.def

@@ -89,6 +89,7 @@ PRIMARY_REQUIRED(const s32, MaxReleaseToOsIntervalMs)
 // Indicates support for offsetting the start of a region by a random number of
 // pages. This is only used if `EnableContiguousRegions` is enabled.
 PRIMARY_OPTIONAL(const bool, EnableRandomOffset, false)
+PRIMARY_OPTIONAL(const s32, DefaultReleaseToOsIntervalMs, INT32_MIN)
 
 // When `EnableContiguousRegions` is true, all regions will be be arranged in
 // adjacency. This will reduce the fragmentation caused by region allocations
@@ -118,6 +119,7 @@ SECONDARY_CACHE_OPTIONAL(const u32, DefaultMaxEntriesCount, 0)
 SECONDARY_CACHE_OPTIONAL(const uptr, DefaultMaxEntrySize, 0)
 SECONDARY_CACHE_OPTIONAL(const s32, MinReleaseToOsIntervalMs, INT32_MIN)
 SECONDARY_CACHE_OPTIONAL(const s32, MaxReleaseToOsIntervalMs, INT32_MAX)
+SECONDARY_CACHE_OPTIONAL(const s32, DefaultReleaseToOsIntervalMs, INT32_MIN)
 
 #undef SECONDARY_CACHE_OPTIONAL
 #undef SECONDARY_REQUIRED_TEMPLATE_TYPE

compiler-rt/lib/scudo/standalone/combined.h

@@ -173,6 +173,9 @@ class Allocator {
         static_cast<u32>(getFlags()->quarantine_max_chunk_size);
 
     Stats.init();
+    // TODO(chiahungduan): Given that we support setting the default value in
+    // the PrimaryConfig and CacheConfig, consider to deprecate the use of
+    // `release_to_os_interval_ms` flag.
     const s32 ReleaseToOsIntervalMs = getFlags()->release_to_os_interval_ms;
     Primary.init(ReleaseToOsIntervalMs);
     Secondary.init(&Stats, ReleaseToOsIntervalMs);

compiler-rt/lib/scudo/standalone/flags.inc

@@ -42,7 +42,7 @@ SCUDO_FLAG(bool, may_return_null, true,
            "returning NULL in otherwise non-fatal error scenarios, eg: OOM, "
            "invalid allocation alignments, etc.")
 
-SCUDO_FLAG(int, release_to_os_interval_ms, SCUDO_ANDROID ? INT32_MIN : 5000,
+SCUDO_FLAG(int, release_to_os_interval_ms, 5000,
            "Interval (in milliseconds) at which to attempt release of unused "
            "memory to the OS. Negative values disable the feature.")
 

compiler-rt/lib/scudo/standalone/primary32.h

@@ -88,6 +88,10 @@ template <typename Config> class SizeClassAllocator32 {
       Sci->MinRegionIndex = NumRegions;
       Sci->ReleaseInfo.LastReleaseAtNs = Time;
     }
+
+    // The default value in the primary config has the higher priority.
+    if (Config::getDefaultReleaseToOsIntervalMs() != INT32_MIN)
+      ReleaseToOsInterval = Config::getDefaultReleaseToOsIntervalMs();
     setOption(Option::ReleaseInterval, static_cast<sptr>(ReleaseToOsInterval));
   }
 

compiler-rt/lib/scudo/standalone/primary64.h

@@ -147,6 +147,9 @@ template <typename Config> class SizeClassAllocator64 {
     for (uptr I = 0; I < NumClasses; I++)
       getRegionInfo(I)->FLLockCV.bindTestOnly(getRegionInfo(I)->FLLock);
 
+    // The default value in the primary config has the higher priority.
+    if (Config::getDefaultReleaseToOsIntervalMs() != INT32_MIN)
+      ReleaseToOsInterval = Config::getDefaultReleaseToOsIntervalMs();
     setOption(Option::ReleaseInterval, static_cast<sptr>(ReleaseToOsInterval));
   }
 

compiler-rt/lib/scudo/standalone/secondary.h

@@ -209,6 +209,9 @@ template <typename Config> class MapAllocatorCache {
               static_cast<sptr>(Config::getDefaultMaxEntriesCount()));
     setOption(Option::MaxCacheEntrySize,
               static_cast<sptr>(Config::getDefaultMaxEntrySize()));
+    // The default value in the cache config has the higher priority.
+    if (Config::getDefaultReleaseToOsIntervalMs() != INT32_MIN)
+      ReleaseToOsInterval = Config::getDefaultReleaseToOsIntervalMs();
     setOption(Option::ReleaseInterval, static_cast<sptr>(ReleaseToOsInterval));
   }