diff options
author | Kostya Serebryany <kcc@google.com> | 2014-02-27 14:38:42 +0000 |
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committer | Kostya Serebryany <kcc@google.com> | 2014-02-27 14:38:42 +0000 |
commit | e68e8f87a47b7cacac6af0f8bd486e36a74a7cac (patch) | |
tree | 6911032acb04753dee19957c5ded38d16acadc36 /lib/sanitizer_common/sanitizer_deadlock_detector.h | |
parent | ccf6a360fb5c80e3f1586f093eb44757d3592745 (diff) |
[sanitizer] do not acquire a global mutex in deadlock detector when dealing with Unlock (it is essentially a thread-local operation)
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@202401 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/sanitizer_common/sanitizer_deadlock_detector.h')
-rw-r--r-- | lib/sanitizer_common/sanitizer_deadlock_detector.h | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/lib/sanitizer_common/sanitizer_deadlock_detector.h b/lib/sanitizer_common/sanitizer_deadlock_detector.h index 30d503def..318288e66 100644 --- a/lib/sanitizer_common/sanitizer_deadlock_detector.h +++ b/lib/sanitizer_common/sanitizer_deadlock_detector.h @@ -48,16 +48,17 @@ class DeadlockDetectorTLS { epoch_ = current_epoch; } + uptr getEpoch() const { return epoch_; } + void addLock(uptr lock_id, uptr current_epoch) { // Printf("addLock: %zx %zx\n", lock_id, current_epoch); CHECK_EQ(epoch_, current_epoch); CHECK(bv_.setBit(lock_id)); } - void removeLock(uptr lock_id, uptr current_epoch) { + void removeLock(uptr lock_id) { // Printf("remLock: %zx %zx\n", lock_id, current_epoch); - CHECK_EQ(epoch_, current_epoch); - bv_.clearBit(lock_id); // May already be cleared due to epoch update. + CHECK(bv_.clearBit(lock_id)); } const BV &getLocks(uptr current_epoch) const { @@ -75,7 +76,8 @@ class DeadlockDetectorTLS { // and one DeadlockDetectorTLS object per evey thread. // This class is not thread safe, all concurrent accesses should be guarded // by an external lock. -// Not thread-safe, all accesses should be protected by an external lock. +// Most of the methods of this class are not thread-safe (i.e. should +// be protected by an external lock) unless explicitly told otherwise. template <class BV> class DeadlockDetector { public: @@ -133,7 +135,7 @@ class DeadlockDetector { } // Handles the lock event, returns true if there is a cycle. - // FIXME: handle RW locks, recusive locks, etc. + // FIXME: handle RW locks, recursive locks, etc. bool onLock(DeadlockDetectorTLS<BV> *dtls, uptr cur_node) { ensureCurrentEpoch(dtls); uptr cur_idx = nodeToIndex(cur_node); @@ -171,10 +173,11 @@ class DeadlockDetector { return res; } - // Handle the unlock event. + // Handle the unlock event. This operation is thread-safe + // as it only touches the dtls. void onUnlock(DeadlockDetectorTLS<BV> *dtls, uptr node) { - ensureCurrentEpoch(dtls); - dtls->removeLock(nodeToIndex(node), current_epoch_); + if (dtls->getEpoch() == nodeToEpoch(node)) + dtls->removeLock(nodeToIndexUnchecked(node)); } bool isHeld(DeadlockDetectorTLS<BV> *dtls, uptr node) const { @@ -202,7 +205,7 @@ class DeadlockDetector { void check_node(uptr node) const { CHECK_GE(node, size()); - CHECK_EQ(current_epoch_, node / size() * size()); + CHECK_EQ(current_epoch_, nodeToEpoch(node)); } uptr indexToNode(uptr idx) const { @@ -210,11 +213,15 @@ class DeadlockDetector { return idx + current_epoch_; } + uptr nodeToIndexUnchecked(uptr node) const { return node % size(); } + uptr nodeToIndex(uptr node) const { check_node(node); - return node % size(); + return nodeToIndexUnchecked(node); } + uptr nodeToEpoch(uptr node) const { return node / size() * size(); } + uptr getAvailableNode(uptr data) { uptr idx = available_nodes_.getAndClearFirstOne(); data_[idx] = data; |