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authorGravatar Chris Kennelly <ckennelly@google.com>2023-10-20 11:44:54 -0700
committerGravatar Copybara-Service <copybara-worker@google.com>2023-10-20 11:45:30 -0700
commit133360ca449bb2a44899e71f253856dca8443bdb (patch)
treea54cfb1dba2476ea802e404c982fc8aba0c17e8f /absl
parent3bc08b8151aa2010960ba24b3b52536f1109f5ba (diff)
Add internal interface to determine if a SpinLock is cooperative.
Some use cases of SpinLock need to verify that it is configured for non-cooperative scheduling. PiperOrigin-RevId: 575278400 Change-Id: Ic49f57a989a3f7f67e346a1ec545f4cd5b94f849
Diffstat (limited to 'absl')
-rw-r--r--absl/base/internal/spinlock.h13
-rw-r--r--absl/base/spinlock_test_common.cc13
2 files changed, 26 insertions, 0 deletions
diff --git a/absl/base/internal/spinlock.h b/absl/base/internal/spinlock.h
index 09ba5824..6818a86a 100644
--- a/absl/base/internal/spinlock.h
+++ b/absl/base/internal/spinlock.h
@@ -41,6 +41,14 @@
#include "absl/base/internal/tsan_mutex_interface.h"
#include "absl/base/thread_annotations.h"
+namespace tcmalloc {
+namespace tcmalloc_internal {
+
+class AllocationGuardSpinLockHolder;
+
+} // namespace tcmalloc_internal
+} // namespace tcmalloc
+
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
@@ -137,6 +145,7 @@ class ABSL_LOCKABLE SpinLock {
// Provide access to protected method above. Use for testing only.
friend struct SpinLockTest;
+ friend class tcmalloc::tcmalloc_internal::AllocationGuardSpinLockHolder;
private:
// lockword_ is used to store the following:
@@ -171,6 +180,10 @@ class ABSL_LOCKABLE SpinLock {
return scheduling_mode == base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL;
}
+ bool IsCooperative() const {
+ return lockword_.load(std::memory_order_relaxed) & kSpinLockCooperative;
+ }
+
uint32_t TryLockInternal(uint32_t lock_value, uint32_t wait_cycles);
void SlowLock() ABSL_ATTRIBUTE_COLD;
void SlowUnlock(uint32_t lock_value) ABSL_ATTRIBUTE_COLD;
diff --git a/absl/base/spinlock_test_common.cc b/absl/base/spinlock_test_common.cc
index 52ecf580..e9047158 100644
--- a/absl/base/spinlock_test_common.cc
+++ b/absl/base/spinlock_test_common.cc
@@ -51,6 +51,8 @@ struct SpinLockTest {
static int64_t DecodeWaitCycles(uint32_t lock_value) {
return SpinLock::DecodeWaitCycles(lock_value);
}
+
+ static bool IsCooperative(const SpinLock& l) { return l.IsCooperative(); }
};
namespace {
@@ -266,6 +268,17 @@ TEST(SpinLockWithThreads, DoesNotDeadlock) {
base_internal::NumCPUs() * 2);
}
+TEST(SpinLockTest, IsCooperative) {
+ SpinLock default_constructor;
+ EXPECT_TRUE(SpinLockTest::IsCooperative(default_constructor));
+
+ SpinLock cooperative(base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL);
+ EXPECT_TRUE(SpinLockTest::IsCooperative(cooperative));
+
+ SpinLock kernel_only(base_internal::SCHEDULE_KERNEL_ONLY);
+ EXPECT_FALSE(SpinLockTest::IsCooperative(kernel_only));
+}
+
} // namespace
} // namespace base_internal
ABSL_NAMESPACE_END