/*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
-#include <folly/ThreadLocal.h>
+#include <folly/detail/ThreadLocalDetail.h>
+
+#include <list>
+#include <mutex>
namespace folly { namespace threadlocal_detail {
-StaticMetaBase::StaticMetaBase(ThreadEntry* (*threadEntry)())
- : nextId_(1), threadEntry_(threadEntry) {
+StaticMetaBase::StaticMetaBase(ThreadEntry* (*threadEntry)(), bool strict)
+ : nextId_(1), threadEntry_(threadEntry), strict_(strict) {
head_.next = head_.prev = &head_;
int ret = pthread_key_create(&pthreadKey_, &onThreadExit);
checkPosixError(ret, "pthread_key_create failed");
#else
std::unique_ptr<ThreadEntry> threadEntry(static_cast<ThreadEntry*>(ptr));
#endif
- DCHECK_GT(threadEntry->elementsCapacity, 0);
+ DCHECK_GT(threadEntry->elementsCapacity, 0u);
auto& meta = *threadEntry->meta;
// Make sure this ThreadEntry is available if ThreadLocal A is accessed in
// ThreadLocal B destructor.
- pthread_setspecific(meta.pthreadKey_, threadEntry);
+ pthread_setspecific(meta.pthreadKey_, &(*threadEntry));
SCOPE_EXIT {
pthread_setspecific(meta.pthreadKey_, nullptr);
};
{
- std::lock_guard<std::mutex> g(meta.lock_);
- meta.erase(&(*threadEntry));
- // No need to hold the lock any longer; the ThreadEntry is private to this
- // thread now that it's been removed from meta.
- }
- // NOTE: User-provided deleter / object dtor itself may be using ThreadLocal
- // with the same Tag, so dispose() calls below may (re)create some of the
- // elements or even increase elementsCapacity, thus multiple cleanup rounds
- // may be required.
- for (bool shouldRun = true; shouldRun;) {
- shouldRun = false;
- FOR_EACH_RANGE (i, 0, threadEntry->elementsCapacity) {
- if (threadEntry->elements[i].dispose(TLPDestructionMode::THIS_THREAD)) {
- shouldRun = true;
+ SharedMutex::ReadHolder rlock(nullptr);
+ if (meta.strict_) {
+ rlock = SharedMutex::ReadHolder(meta.accessAllThreadsLock_);
+ }
+ {
+ std::lock_guard<std::mutex> g(meta.lock_);
+ meta.erase(&(*threadEntry));
+ // No need to hold the lock any longer; the ThreadEntry is private to this
+ // thread now that it's been removed from meta.
+ }
+ // NOTE: User-provided deleter / object dtor itself may be using ThreadLocal
+ // with the same Tag, so dispose() calls below may (re)create some of the
+ // elements or even increase elementsCapacity, thus multiple cleanup rounds
+ // may be required.
+ for (bool shouldRun = true; shouldRun;) {
+ shouldRun = false;
+ FOR_EACH_RANGE (i, 0, threadEntry->elementsCapacity) {
+ if (threadEntry->elements[i].dispose(TLPDestructionMode::THIS_THREAD)) {
+ shouldRun = true;
+ }
}
}
}
void StaticMetaBase::destroy(EntryID* ent) {
try {
auto& meta = *this;
+
// Elements in other threads that use this id.
std::vector<ElementWrapper> elements;
+
{
- std::lock_guard<std::mutex> g(meta.lock_);
- uint32_t id = ent->value.exchange(kEntryIDInvalid);
- if (id == kEntryIDInvalid) {
- return;
+ SharedMutex::WriteHolder wlock(nullptr);
+ if (meta.strict_) {
+ /*
+ * In strict mode, the logic guarantees per-thread instances are
+ * destroyed by the moment ThreadLocal<> dtor returns.
+ * In order to achieve that, we should wait until concurrent
+ * onThreadExit() calls (that might acquire ownership over per-thread
+ * instances in order to destroy them) are finished.
+ */
+ wlock = SharedMutex::WriteHolder(meta.accessAllThreadsLock_);
}
- for (ThreadEntry* e = meta.head_.next; e != &meta.head_; e = e->next) {
- if (id < e->elementsCapacity && e->elements[id].ptr) {
- elements.push_back(e->elements[id]);
-
- /*
- * Writing another thread's ThreadEntry from here is fine;
- * the only other potential reader is the owning thread --
- * from onThreadExit (which grabs the lock, so is properly
- * synchronized with us) or from get(), which also grabs
- * the lock if it needs to resize the elements vector.
- *
- * We can't conflict with reads for a get(id), because
- * it's illegal to call get on a thread local that's
- * destructing.
- */
- e->elements[id].ptr = nullptr;
- e->elements[id].deleter1 = nullptr;
- e->elements[id].ownsDeleter = false;
+ {
+ std::lock_guard<std::mutex> g(meta.lock_);
+ uint32_t id = ent->value.exchange(kEntryIDInvalid);
+ if (id == kEntryIDInvalid) {
+ return;
}
+
+ for (ThreadEntry* e = meta.head_.next; e != &meta.head_; e = e->next) {
+ if (id < e->elementsCapacity && e->elements[id].ptr) {
+ elements.push_back(e->elements[id]);
+
+ /*
+ * Writing another thread's ThreadEntry from here is fine;
+ * the only other potential reader is the owning thread --
+ * from onThreadExit (which grabs the lock, so is properly
+ * synchronized with us) or from get(), which also grabs
+ * the lock if it needs to resize the elements vector.
+ *
+ * We can't conflict with reads for a get(id), because
+ * it's illegal to call get on a thread local that's
+ * destructing.
+ */
+ e->elements[id].ptr = nullptr;
+ e->elements[id].deleter1 = nullptr;
+ e->elements[id].ownsDeleter = false;
+ }
+ }
+ meta.freeIds_.push_back(id);
}
- meta.freeIds_.push_back(id);
}
- // Delete elements outside the lock
+ // Delete elements outside the locks.
for (ElementWrapper& elem : elements) {
elem.dispose(TLPDestructionMode::ALL_THREADS);
}
free(reallocated);
}
+
FOLLY_STATIC_CTOR_PRIORITY_MAX
PthreadKeyUnregister PthreadKeyUnregister::instance_;
-}}
+} // namespace threadlocal_detail
+} // namespace folly
projects / folly.git / blobdiff