Enable madvise autoreset by default for shared system USM

Signed-off-by: John Falkowski <john.falkowski@intel.com>

Author: johntfalk

shared/source/debug_settings/debug_variables_base.inl

@@ -533,6 +533,7 @@ DECLARE_DEBUG_VARIABLE(int32_t, RenderCompressedImagesEnabled, -1, "-1: default,
 DECLARE_DEBUG_VARIABLE(int32_t, RenderCompressedBuffersEnabled, -1, "-1: default, 0: disabled, 1: enabled")
 DECLARE_DEBUG_VARIABLE(int32_t, EnableUsmConcurrentAccessSupport, 0, "0: default, >0: bitmask with usm capabilities to enable concurrent access for (bit0: host, bit1: device, bit2: shared single-device, bit3: shared cross-device, bit4: shared system)")
 DECLARE_DEBUG_VARIABLE(int32_t, EnableSharedSystemUsmSupport, -1, "-1: default, 0: shared system memory disabled, 1: shared system memory enabled")
+DECLARE_DEBUG_VARIABLE(int32_t, DisableMadviseAutoReset, 0, "0: default, madvise autoreset vm_bind flag not disabled , 1: madvise autoreset vm_bind flag disabled")
 DECLARE_DEBUG_VARIABLE(int32_t, EnablePassInlineData, -1, "-1: default, 0: Do not allow to pass inline data 1: Enable passing of inline data")
 DECLARE_DEBUG_VARIABLE(int32_t, ForceFineGrainedSVMSupport, -1, "-1: default, 0: Do not report Fine Grained SVM capabilities 1: Report SVM Fine Grained capabilities if device supports SVM")
 DECLARE_DEBUG_VARIABLE(int32_t, UseAsyncDrmExec, -1, "-1: default, 0: Disabled 1: Enabled. If enabled, pass EXEC_OBJECT_ASYNC to exec ioctl.")

shared/source/os_interface/linux/drm_neo.cpp

@@ -1730,7 +1730,11 @@ int Drm::createDrmVirtualMemory(uint32_t &drmVmId) {
             auto &productHelper = rootDeviceEnvironment.getHelper<ProductHelper>();
             VmBindParams vmBind{};
             vmBind.vmId = static_cast<uint32_t>(ctl.vmId);
-            vmBind.flags = DRM_XE_VM_BIND_FLAG_CPU_ADDR_MIRROR;
+            if (debugManager.flags.DisableMadviseAutoReset.get() == 1) {
+                vmBind.flags = DRM_XE_VM_BIND_FLAG_CPU_ADDR_MIRROR;
+            } else {
+                vmBind.flags = DRM_XE_VM_BIND_FLAG_CPU_ADDR_MIRROR | DRM_XE_VM_BIND_FLAG_MADVISE_AUTORESET;
+            }
             vmBind.length = this->getSharedSystemAllocAddressRange();
             vmBind.sharedSystemUsmEnabled = true;
             vmBind.sharedSystemUsmBind = true;

shared/test/common/test_files/igdrcl.config

@@ -189,6 +189,7 @@ EnableStateComputeModeTracking = -1
 EnableSetPair = -1
 EnableUsmConcurrentAccessSupport = 0
 EnableSharedSystemUsmSupport = -1
+DisableMadviseAutoReset = 0
 EnablePassInlineData = -1
 ForceFineGrainedSVMSupport = -1
 EnableImmediateCmdListHeapSharing = -1

third_party/uapi/drm-next/xe/xe_drm.h

@@ -3,8 +3,8 @@
  * Copyright © 2023 Intel Corporation
  */
 
-#ifndef _XE_DRM_H_
-#define _XE_DRM_H_
+#ifndef _UAPI_XE_DRM_H_
+#define _UAPI_XE_DRM_H_
 
 #include "drm.h"
 
@@ -140,7 +140,7 @@ extern "C" {
  * redefine the interface more easily than an ever growing struct of
  * increasing complexity, and for large parts of that interface to be
  * entirely optional. The downside is more pointer chasing; chasing across
- * the boundary with pointers encapsulated inside u64.
+ * the __user boundary with pointers encapsulated inside u64.
  *
  * Example chaining:
  *
@@ -1013,6 +1013,20 @@ struct drm_xe_vm_destroy {
  *    valid on VMs with DRM_XE_VM_CREATE_FLAG_FAULT_MODE set. The CPU address
  *    mirror flag are only valid for DRM_XE_VM_BIND_OP_MAP operations, the BO
  *    handle MBZ, and the BO offset MBZ.
+ *  - %DRM_XE_VM_BIND_FLAG_MADVISE_AUTORESET - Can be used in combination with
+ *    %DRM_XE_VM_BIND_FLAG_CPU_ADDR_MIRROR to reset madvises when the underlying
+ *    CPU address space range is unmapped (typically with munmap(2) or brk(2)).
+ *    The madvise values set with %DRM_IOCTL_XE_MADVISE are reset to the values
+ *    that were present immediately after the %DRM_IOCTL_XE_VM_BIND.
+ *    The reset GPU virtual address range is the intersection of the range bound
+ *    using %DRM_IOCTL_XE_VM_BIND and the virtual CPU address space range
+ *    unmapped.
+ *    This functionality is present to mimic the behaviour of CPU address space
+ *    madvises set using madvise(2), which are typically reset on unmap.
+ *    Note: free(3) may or may not call munmap(2) and/or brk(2), and may thus
+ *    not invoke autoreset. Neither will stack variables going out of scope.
+ *    Therefore it's recommended to always explicitly reset the madvises when
+ *    freeing the memory backing a region used in a %DRM_IOCTL_XE_MADVISE call.
  *
  * The @prefetch_mem_region_instance for %DRM_XE_VM_BIND_OP_PREFETCH can also be:
  *  - %DRM_XE_CONSULT_MEM_ADVISE_PREF_LOC, which ensures prefetching occurs in
@@ -1119,6 +1133,7 @@ struct drm_xe_vm_bind_op {
 #define DRM_XE_VM_BIND_FLAG_DUMPABLE	(1 << 3)
 #define DRM_XE_VM_BIND_FLAG_CHECK_PXP	(1 << 4)
 #define DRM_XE_VM_BIND_FLAG_CPU_ADDR_MIRROR	(1 << 5)
+#define DRM_XE_VM_BIND_FLAG_MADVISE_AUTORESET	(1 << 6)
 	/** @flags: Bind flags */
 	__u32 flags;
 
@@ -2258,4 +2273,4 @@ struct drm_xe_vm_query_mem_range_attr {
 }
 #endif
 
-#endif /* _XE_DRM_H_ */
+#endif /* _UAPI_XE_DRM_H_ */