fix(sysman): fixes multithread access issue with FDCache

Related-To: NEO-9720

Signed-off-by: Kulkarni, Ashwin Kumar <[email protected]>
Source: a064388

Author: AshwinKumarKulkarni

level_zero/sysman/source/shared/linux/sysman_fs_access_interface.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2023 Intel Corporation
+ * Copyright (C) 2023-2024 Intel Corporation
  *
  * SPDX-License-Identifier: MIT
  *
@@ -45,6 +45,7 @@ void FdCacheInterface::eraseLeastUsedEntryFromCache() {
 }
 
 int FdCacheInterface::getFd(std::string file) {
+    std::unique_lock<std::mutex> lock(fdMutex);
     int fd = -1;
     if (fdMap.find(file) == fdMap.end()) {
         fd = NEO::SysCalls::open(file.c_str(), O_RDONLY);
@@ -550,4 +551,4 @@ bool SysFsAccessInterface::isRootUser() {
 }
 
 } // namespace Sysman
-} // namespace L0
+} // namespace L0

level_zero/sysman/source/shared/linux/sysman_fs_access_interface.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2023 Intel Corporation
+ * Copyright (C) 2023-2024 Intel Corporation
  *
  * SPDX-License-Identifier: MIT
  *
@@ -13,6 +13,7 @@
 
 #include <map>
 #include <memory>
+#include <mutex>
 #include <vector>
 
 namespace L0 {
@@ -31,6 +32,7 @@ class FdCacheInterface {
     std::map<std::string, std::pair<int, uint32_t>> fdMap = {};
 
   private:
+    std::mutex fdMutex{};
     void eraseLeastUsedEntryFromCache();
 };
 
@@ -142,4 +144,4 @@ class SysFsAccessInterface : protected FsAccessInterface {
 };
 
 } // namespace Sysman
-} // namespace L0
+} // namespace L0

level_zero/sysman/test/unit_tests/sources/linux/test_sysman.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020-2023 Intel Corporation
+ * Copyright (C) 2020-2024 Intel Corporation
  *
  * SPDX-License-Identifier: MIT
  *
@@ -257,6 +257,35 @@ TEST(FdCacheTest, GivenValidFdCacheWhenCallingGetFdOnSameFileThenVerifyCacheIsUp
     EXPECT_EQ(pFdCache->fdMap.end(), pFdCache->fdMap.find("mockfile9.txt"));
 }
 
+TEST(FdCacheTest, GivenValidFdCacheWhenCallingGetFdOnMultipleFilesManyTimesThenVerifyCacheIsUpdatedCorrectly) {
+
+    class MockFdCache : public FdCacheInterface {
+      public:
+        using FdCacheInterface::fdMap;
+    };
+
+    VariableBackup<decltype(NEO::SysCalls::sysCallsOpen)> mockOpen(&NEO::SysCalls::sysCallsOpen, [](const char *pathname, int flags) -> int {
+        return 1;
+    });
+
+    std::unique_ptr<MockFdCache> pFdCache = std::make_unique<MockFdCache>();
+    std::string fileName = {};
+    for (auto i = 0; i < L0::Sysman::FdCacheInterface::maxSize; i++) {
+        fileName = "mockfile" + std::to_string(i) + ".txt";
+        int j = i + 1;
+        while (j--) {
+            EXPECT_LE(0, pFdCache->getFd(fileName));
+        }
+    }
+
+    // replace a least referred file and add new file
+    fileName = "mockfile100.txt";
+    EXPECT_LE(0, pFdCache->getFd(fileName));
+
+    // Verify cache doesn't have an element that is accessed less number of times.
+    EXPECT_EQ(pFdCache->fdMap.end(), pFdCache->fdMap.find("mockfile0.txt"));
+}
+
 TEST(FdCacheTest, GivenValidFdCacheWhenClearingCacheThenVerifyProperFdsAreClosedAndCacheIsUpdatedProperly) {
 
     class MockFdCache : public FdCache {

level_zero/tools/source/sysman/linux/fs_access.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020-2023 Intel Corporation
+ * Copyright (C) 2020-2024 Intel Corporation
  *
  * SPDX-License-Identifier: MIT
  *
@@ -46,6 +46,7 @@ void FdCache::eraseLeastUsedEntryFromCache() {
 }
 
 int FdCache::getFd(std::string file) {
+    std::unique_lock<std::mutex> lock(fdMutex);
     int fd = -1;
     if (fdMap.find(file) == fdMap.end()) {
         fd = NEO::SysCalls::open(file.c_str(), O_RDONLY);

level_zero/tools/source/sysman/linux/fs_access.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020-2023 Intel Corporation
+ * Copyright (C) 2020-2024 Intel Corporation
  *
  * SPDX-License-Identifier: MIT
  *
@@ -18,6 +18,7 @@
 #include <list>
 #include <map>
 #include <memory>
+#include <mutex>
 #include <sstream>
 #include <string>
 #include <sys/stat.h>
@@ -41,6 +42,7 @@ class FdCache {
     std::map<std::string, std::pair<int, uint32_t>> fdMap = {};
 
   private:
+    std::mutex fdMutex{};
     void eraseLeastUsedEntryFromCache();
 };
 

level_zero/tools/test/unit_tests/sources/sysman/linux/test_sysman.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020-2023 Intel Corporation
+ * Copyright (C) 2020-2024 Intel Corporation
  *
  * SPDX-License-Identifier: MIT
  *
@@ -540,6 +540,35 @@ TEST(FdCacheTest, GivenValidFdCacheWhenClearingCacheThenVerifyProperFdsAreClosed
     delete pFdCache;
 }
 
+TEST(FdCacheTest, GivenValidFdCacheWhenCallingGetFdOnMultipleFilesManyTimesThenVerifyCacheIsUpdatedCorrectly) {
+
+    class MockFdCache : public FdCache {
+      public:
+        using FdCache::fdMap;
+    };
+
+    VariableBackup<decltype(NEO::SysCalls::sysCallsOpen)> mockOpen(&NEO::SysCalls::sysCallsOpen, [](const char *pathname, int flags) -> int {
+        return 1;
+    });
+
+    std::unique_ptr<MockFdCache> pFdCache = std::make_unique<MockFdCache>();
+    std::string fileName = {};
+    for (auto i = 0; i < L0::FdCache::maxSize; i++) {
+        fileName = "mockfile" + std::to_string(i) + ".txt";
+        int j = i + 1;
+        while (j--) {
+            EXPECT_LE(0, pFdCache->getFd(fileName));
+        }
+    }
+
+    // replace a least referred file and add new file
+    fileName = "mockfile100.txt";
+    EXPECT_LE(0, pFdCache->getFd(fileName));
+
+    // Verify cache doesn't have an element that is accessed less number of times.
+    EXPECT_EQ(pFdCache->fdMap.end(), pFdCache->fdMap.find("mockfile0.txt"));
+}
+
 TEST_F(SysmanDeviceFixture, GivenSysfsAccessClassAndUnsignedIntegerWhenCallingReadThenSuccessIsReturned) {
 
     VariableBackup<decltype(NEO::SysCalls::sysCallsOpen)> mockOpen(&NEO::SysCalls::sysCallsOpen, [](const char *pathname, int flags) -> int {