[vlc-devel] [PATCH 4/6] thread: remove the mutex mark system
Rémi Denis-Courmont
remi at remlab.net
Thu Feb 20 20:58:21 CET 2020
This is now redundant.
---
include/vlc_threads.h | 13 +++---
src/libvlc.h | 15 -------
src/libvlccore.sym | 2 +-
src/misc/threads.c | 100 +-----------------------------------------
src/player/player.c | 6 +--
5 files changed, 11 insertions(+), 125 deletions(-)
diff --git a/include/vlc_threads.h b/include/vlc_threads.h
index 0aa1dbca05..02060cc775 100644
--- a/include/vlc_threads.h
+++ b/include/vlc_threads.h
@@ -400,18 +400,17 @@ VLC_API void vlc_mutex_unlock(vlc_mutex_t *);
* This function has no effects.
* It is only meant to be use in run-time assertions.
*
- * @retval false in debug builds of LibVLC,
- * if the mutex is not locked by the calling thread;
- * @retval true in debug builds of LibVLC,
- * if the mutex is locked by the calling thread;
- * @retval true in release builds of LibVLC.
+ * @warning This function might not return correct results in non-debug builds.
+ *
+ * @retval false the mutex is not locked by the calling thread
+ * @retval true the mutex is locked by the calling thread
*/
-VLC_API bool vlc_mutex_marked(const vlc_mutex_t *) VLC_USED;
+VLC_API bool vlc_mutex_held(const vlc_mutex_t *) VLC_USED;
/**
* Asserts that a mutex is locked by the calling thread.
*/
-#define vlc_mutex_assert(m) assert(vlc_mutex_marked(m))
+#define vlc_mutex_assert(m) assert(vlc_mutex_held(m))
/** @} */
diff --git a/src/libvlc.h b/src/libvlc.h
index ff50bd9218..e91587f947 100644
--- a/src/libvlc.h
+++ b/src/libvlc.h
@@ -54,21 +54,6 @@ void vlc_threads_setup (libvlc_int_t *);
void vlc_trace (const char *fn, const char *file, unsigned line);
#define vlc_backtrace() vlc_trace(__func__, __FILE__, __LINE__)
-#ifndef NDEBUG
-/**
- * Marks a mutex locked.
- */
-void vlc_mutex_mark(const vlc_mutex_t *);
-
-/**
- * Unmarks a mutex.
- */
-void vlc_mutex_unmark(const vlc_mutex_t *);
-#else
-# define vlc_mutex_mark(m) ((void)(m))
-# define vlc_mutex_unmark(m) ((void)(m))
-#endif
-
/*
* Logging
*/
diff --git a/src/libvlccore.sym b/src/libvlccore.sym
index 1d9e521662..a0efbecb78 100644
--- a/src/libvlccore.sym
+++ b/src/libvlccore.sym
@@ -619,7 +619,7 @@ vlc_mutex_init_recursive
vlc_mutex_lock
vlc_mutex_trylock
vlc_mutex_unlock
-vlc_mutex_marked
+vlc_mutex_held
vlc_global_mutex
vlc_object_create
vlc_object_delete
diff --git a/src/misc/threads.c b/src/misc/threads.c
index eddf06d348..c4fd617882 100644
--- a/src/misc/threads.c
+++ b/src/misc/threads.c
@@ -62,99 +62,6 @@ void vlc_global_mutex (unsigned n, bool acquire)
vlc_mutex_unlock (lock);
}
-#ifndef NDEBUG
-# ifdef HAVE_SEARCH_H
-# include <search.h>
-# endif
-
-struct vlc_lock_mark
-{
- const void *object;
- uintptr_t refs;
-};
-
-static int vlc_lock_mark_cmp(const void *a, const void *b)
-{
- const struct vlc_lock_mark *ma = a, *mb = b;
-
- if (ma->object == mb->object)
- return 0;
-
- return ((uintptr_t)(ma->object) > (uintptr_t)(mb->object)) ? +1 : -1;
-}
-
-static void vlc_lock_mark(const void *lock, void **rootp)
-{
- struct vlc_lock_mark *mark = malloc(sizeof (*mark));
- if (unlikely(mark == NULL))
- abort();
-
- mark->object = lock;
- mark->refs = 0;
-
- void **entry = tsearch(mark, rootp, vlc_lock_mark_cmp);
- if (unlikely(entry == NULL))
- abort();
-
- if (unlikely(*entry != mark)) {
- /* Recursive locking: lock is already in the tree */
- free(mark);
- mark = *entry;
- }
-
- mark->refs++;
-}
-
-static void vlc_lock_unmark(const void *lock, void **rootp)
-{
- struct vlc_lock_mark *mark = &(struct vlc_lock_mark){ lock, 0 };
- void **entry = tfind(mark, rootp, vlc_lock_mark_cmp);
-
- assert(entry != NULL);
- mark = *entry;
- assert(mark->refs > 0);
-
- if (likely(--mark->refs == 0)) {
- tdelete(mark, rootp, vlc_lock_mark_cmp);
- free(mark);
- }
-}
-
-static bool vlc_lock_marked(const void *lock, void **rootp)
-{
- struct vlc_lock_mark *mark = &(struct vlc_lock_mark){ lock, 0 };
-
- return tfind(mark, rootp, vlc_lock_mark_cmp) != NULL;
-}
-
-static _Thread_local void *vlc_mutex_marks = NULL;
-
-void vlc_mutex_mark(const vlc_mutex_t *mutex)
-{
- vlc_lock_mark(mutex, &vlc_mutex_marks);
-}
-
-void vlc_mutex_unmark(const vlc_mutex_t *mutex)
-{
- vlc_lock_unmark(mutex, &vlc_mutex_marks);
-}
-
-bool vlc_mutex_marked(const vlc_mutex_t *mutex)
-{
- return vlc_lock_marked(mutex, &vlc_mutex_marks);
-}
-#else
-bool vlc_mutex_marked(const vlc_mutex_t *mutex)
-{
- return true;
-}
-#endif
-
-#if defined (_WIN32) && (_WIN32_WINNT < _WIN32_WINNT_WIN8)
-/* Cannot define OS version-dependent stuff in public headers */
-# undef LIBVLC_NEED_SLEEP
-#endif
-
#if defined(_WIN32) || defined(__ANDROID__)
static void do_vlc_cancel_addr_clear(void *addr)
{
@@ -229,7 +136,7 @@ void vlc_mutex_destroy(vlc_mutex_t *mtx)
static _Thread_local char thread_self[1];
#define THREAD_SELF ((const void *)thread_self)
-static bool vlc_mutex_held(const vlc_mutex_t *mtx)
+bool vlc_mutex_held(const vlc_mutex_t *mtx)
{
/* This comparison is thread-safe:
* Even though other threads may modify the owner field at any time,
@@ -260,7 +167,6 @@ void vlc_mutex_lock(vlc_mutex_t *mtx)
vlc_restorecancel(canc);
atomic_store_explicit(&mtx->owner, THREAD_SELF, memory_order_relaxed);
- vlc_mutex_mark(mtx);
}
int vlc_mutex_trylock(vlc_mutex_t *mtx)
@@ -278,7 +184,6 @@ int vlc_mutex_trylock(vlc_mutex_t *mtx)
*/
atomic_store_explicit(&mtx->recursion, recursion + 1,
memory_order_relaxed);
- vlc_mutex_mark(mtx);
return 0;
} else
assert(!vlc_mutex_held(mtx));
@@ -289,7 +194,6 @@ int vlc_mutex_trylock(vlc_mutex_t *mtx)
memory_order_acquire,
memory_order_relaxed)) {
atomic_store_explicit(&mtx->owner, THREAD_SELF, memory_order_relaxed);
- vlc_mutex_mark(mtx);
return 0;
}
@@ -306,12 +210,10 @@ void vlc_mutex_unlock(vlc_mutex_t *mtx)
/* Non-last recursive unlocking. */
atomic_store_explicit(&mtx->recursion, recursion - 1,
memory_order_relaxed);
- vlc_mutex_unmark(mtx);
return;
}
atomic_store_explicit(&mtx->owner, NULL, memory_order_relaxed);
- vlc_mutex_unmark(mtx);
switch (atomic_exchange_explicit(&mtx->value, 0, memory_order_release)) {
case 2:
diff --git a/src/player/player.c b/src/player/player.c
index 89c16caf6a..48c03905a4 100644
--- a/src/player/player.c
+++ b/src/player/player.c
@@ -914,11 +914,11 @@ vlc_player_Lock(vlc_player_t *player)
{
/* Vout and aout locks should not be held, cf. vlc_player_vout_cbs and
* vlc_player_aout_cbs documentation */
- assert(!vlc_mutex_marked(&player->vout_listeners_lock));
- assert(!vlc_mutex_marked(&player->aout_listeners_lock));
+ assert(!vlc_mutex_held(&player->vout_listeners_lock));
+ assert(!vlc_mutex_held(&player->aout_listeners_lock));
/* The timer lock should not be held (possible lock-order-inversion), cf.
* vlc_player_timer_cbs.on_update documentation */
- assert(!vlc_mutex_marked(&player->timer.lock));
+ assert(!vlc_mutex_held(&player->timer.lock));
vlc_mutex_lock(&player->lock);
}
--
2.25.0
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