kc3-lang/angle/src/libANGLE/GlobalMutex_unittest.cpp

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• Hash : e5619a5c
  Author :
  Date : 2024-10-15T18:27:00
  

  Use EGL sync global lock for all EGL*sync entrypoint calls
  
  To free EGL sync operations from waiting for other EGL calls
  to finish, we use a separate global lock for EGL*sync entrypoints.
  Below angle::SimpleMutex are added to protect resources that may
  have race condition due to being accessed by EGL*sync calls
  and non EGL*sync calls at the same time:
  
  1. Display::mContextMapMutex that protects Display::mState.contextMap
  
  2. static angle::base::NoDestructor<angle::SimpleMutex>
  anglePlatformDisplayMapMutex that protects static
  angle::base::NoDestructor<ANGLEPlatformDisplayMap> displays
  
  3. static angle::base::NoDestructor<angle::SimpleMutex>
  devicePlatformDisplayMapMutex that protects static
  angle::base::NoDestructor<DevicePlatformDisplayMap> displays
  
  EGL_Terminate() entry point takes both global lock and
  global egl sync lock. This is to protect Display::mSyncMap,
  Display::mSyncPools, and Display::mSyncHandleAllocator being
  get cleared by thread 1 calling eglTerminate, while they are
  still accessed by thread 2 through a call such as eglCreateSync.
  So that we won't have thread 2 finish validating the sync object with
  syncID exists in Display::mSyncMap, but then find the
  mSyncMap.find(syncID) returns a nullptr due to the mSyncMap
  is cleared by thread 1. Same applies to EGL_LabelObjectKHR(),
  EGL_ReleaseThread(), ThreadCleanupCallback().
  
  EGL_Initialize() writes to Display::mInitialized. This is read
  by EGL Sync API validation functions. EGL_Initialize() also takes
  both global lock and global sync lock to prevent race conditions
  between EGL_Initialize() and EGL Sync APIs.
  
  When ANGLE_CAPTURE_ENABLED is enabled, fall back to global lock,
  as the CaptureEGLCallToFrameCapture() touches many resources
  (e.g. mMaxAccessedResourceIDs, mFrameCalls)
  that could lead to race conditions without a global lock.
  
  Bug: b/362604439
  Change-Id: Ic0d54a4cd66743bcd0f48f41f247dd223cff2f5e
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5933570
  Reviewed-by: Roman Lavrov <romanl@google.com>
  Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
  Reviewed-by: Igor Nazarov <i.nazarov@samsung.com>
  Commit-Queue: Yuxin Hu <yuxinhu@google.com>
  

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• src/libANGLE/GlobalMutex_unittest.cpp

• //
  // Copyright 2023 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  // GlobalMutex_unittest:
  //   Tests of the Scoped<*>GlobalMutexLock classes
  //
  
  #include <gtest/gtest.h>
  
  #include "libANGLE/GlobalMutex.h"
  
  namespace
  {
  template <class ScopedGlobalLockT, class... Args>
  void runBasicGlobalMutexTest(bool expectToPass, Args &&...args)
  {
      constexpr size_t kThreadCount    = 16;
      constexpr size_t kIterationCount = 50'000;
  
      std::array<std::thread, kThreadCount> threads;
  
      std::mutex mutex;
      std::condition_variable condVar;
      size_t readyCount = 0;
  
      std::atomic<size_t> testVar;
  
      for (size_t i = 0; i < kThreadCount; ++i)
      {
          threads[i] = std::thread([&]() {
              {
                  std::unique_lock<std::mutex> lock(mutex);
                  ++readyCount;
                  if (readyCount < kThreadCount)
                  {
                      condVar.wait(lock, [&]() { return readyCount == kThreadCount; });
                  }
                  else
                  {
                      condVar.notify_all();
                  }
              }
              for (size_t j = 0; j < kIterationCount; ++j)
              {
                  ScopedGlobalLockT lock(std::forward<Args>(args)...);
                  const int local    = testVar.load(std::memory_order_relaxed);
                  const int newValue = local + 1;
                  testVar.store(newValue, std::memory_order_relaxed);
              }
          });
      }
  
      for (size_t i = 0; i < kThreadCount; ++i)
      {
          threads[i].join();
      }
  
      if (expectToPass)
      {
          EXPECT_EQ(testVar.load(), kThreadCount * kIterationCount);
      }
      else
      {
          EXPECT_LE(testVar.load(), kThreadCount * kIterationCount);
      }
  }
  
  // Tests basic usage of ScopedGlobalEGLMutexLock.
  TEST(GlobalMutexTest, ScopedGlobalEGLMutexLock)
  {
      runBasicGlobalMutexTest<egl::ScopedGlobalEGLMutexLock>(true);
  }
  
  // Tests basic usage of ScopedOptionalGlobalMutexLock (Enabled).
  TEST(GlobalMutexTest, ScopedOptionalGlobalMutexLockEnabled)
  {
      runBasicGlobalMutexTest<egl::ScopedOptionalGlobalMutexLock>(true, true);
  }
  
  // Tests basic usage of ScopedOptionalGlobalMutexLock (Disabled).
  TEST(GlobalMutexTest, ScopedOptionalGlobalMutexLockDisabled)
  {
      runBasicGlobalMutexTest<egl::ScopedOptionalGlobalMutexLock>(false, false);
  }
  
  #if defined(ANGLE_ENABLE_GLOBAL_MUTEX_RECURSION)
  // Tests that ScopedGlobalEGLMutexLock can be recursively locked.
  TEST(GlobalMutexTest, RecursiveScopedGlobalEGLMutexLock)
  {
      egl::ScopedGlobalEGLMutexLock lock;
      egl::ScopedGlobalEGLMutexLock lock2;
  }
  
  // Tests that ScopedOptionalGlobalMutexLock can be recursively locked.
  TEST(GlobalMutexTest, RecursiveScopedOptionalGlobalMutexLock)
  {
      egl::ScopedOptionalGlobalMutexLock lock(true);
      egl::ScopedOptionalGlobalMutexLock lock2(true);
  }
  #endif
  
  }  // anonymous namespace
  

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