Broadcast signal to all threads while handling USM pagefault

Related-To: NEO-4721

Change-Id: I77185f8db2576f626c1b6b5615ab5d8f9b22076f
Signed-off-by: Lukasz Jobczyk <lukasz.jobczyk@intel.com>

shared/test/unit_test/page_fault_manager/linux/cpu_page_fault_manager_linux_tests.cpp

@@ -13,12 +13,59 @@
 
 #include <csignal>
 #include <sys/mman.h>
+#include <sys/syscall.h>
+#include <thread>
+#include <unistd.h>
 
 using namespace NEO;
 
 using PageFaultManagerLinuxTest = PageFaultManagerConfigFixture;
 using MockPageFaultManagerLinux = MockPageFaultManagerHandlerInvoke<PageFaultManagerLinux>;
 
+struct UserSignalMockPageFaultManagerLinux : public PageFaultManagerLinux {
+    using PageFaultManager::verifyPageFault;
+
+    UserSignalMockPageFaultManagerLinux() {
+        ownThread = std::thread([&]() {
+            while (!waitForCopyCalled) {
+                if (ownThreadId == -1) {
+                    ownThreadId = static_cast<int>(syscall(__NR_gettid));
+                }
+            }
+        });
+        while (ownThreadId == -1) {
+        }
+    }
+
+    void allowCPUMemoryAccess(void *ptr, size_t size) override {}
+    void transferToCpu(void *ptr, size_t size, void *cmdQ) override {}
+    void setAubWritable(bool writable, void *ptr, SVMAllocsManager *unifiedMemoryManager) override {}
+
+    void sendSignalToThread(int threadId) override {
+        PageFaultManagerLinux::sendSignalToThread(ownThreadId);
+    }
+
+    void waitForCopy() override {
+        PageFaultManagerLinux::waitForCopy();
+        waitForCopyCalled = true;
+    }
+
+    std::thread ownThread;
+    int ownThreadId = -1;
+    bool waitForCopyCalled = false;
+};
+
+TEST_F(PageFaultManagerLinuxTest, whenVeryfyingPageFaultThenUserSignalIsSentToOtherThreads) {
+    auto pageFaultManager = std::make_unique<UserSignalMockPageFaultManagerLinux>();
+
+    auto alloc = reinterpret_cast<void *>(0x1);
+    pageFaultManager->insertAllocation(alloc, 10, nullptr, nullptr);
+    pageFaultManager->verifyPageFault(alloc);
+    pageFaultManager->ownThread.join();
+
+    EXPECT_TRUE(pageFaultManager->waitForCopyCalled);
+}
+
 TEST_F(PageFaultManagerLinuxTest, whenPageFaultIsRaisedThenHandlerIsInvoked) {
     auto pageFaultManager = std::make_unique<MockPageFaultManagerLinux>();
     EXPECT_FALSE(pageFaultManager->handlerInvoked);

shared/test/unit_test/page_fault_manager/mock_cpu_page_fault_manager.h

@@ -49,6 +49,7 @@ class MockPageFaultManager : public PageFaultManager {
     void baseGpuTransfer(void *ptr, void *cmdQ) {
         PageFaultManager::transferToGpu(ptr, cmdQ);
     }
+    void broadcastWaitSignal() override {}
 
     int allowMemoryAccessCalled = 0;
     int protectMemoryCalled = 0;