diff options
| -rw-r--r-- | qemu-coroutine.c | 92 |
1 files changed, 41 insertions, 51 deletions
diff --git a/qemu-coroutine.c b/qemu-coroutine.c index bd574aa1b5..93fddc7dfb 100644 --- a/qemu-coroutine.c +++ b/qemu-coroutine.c @@ -15,31 +15,57 @@ #include "trace.h" #include "qemu-common.h" #include "qemu/thread.h" +#include "qemu/atomic.h" #include "block/coroutine.h" #include "block/coroutine_int.h" enum { - POOL_DEFAULT_SIZE = 64, + POOL_BATCH_SIZE = 64, }; /** Free list to speed up creation */ -static QemuMutex pool_lock; -static QSLIST_HEAD(, Coroutine) pool = QSLIST_HEAD_INITIALIZER(pool); -static unsigned int pool_size; -static unsigned int pool_max_size = POOL_DEFAULT_SIZE; +static QSLIST_HEAD(, Coroutine) release_pool = QSLIST_HEAD_INITIALIZER(pool); +static unsigned int release_pool_size; +static __thread QSLIST_HEAD(, Coroutine) alloc_pool = QSLIST_HEAD_INITIALIZER(pool); +static __thread Notifier coroutine_pool_cleanup_notifier; + +static void coroutine_pool_cleanup(Notifier *n, void *value) +{ + Coroutine *co; + Coroutine *tmp; + + QSLIST_FOREACH_SAFE(co, &alloc_pool, pool_next, tmp) { + QSLIST_REMOVE_HEAD(&alloc_pool, pool_next); + qemu_coroutine_delete(co); + } +} Coroutine *qemu_coroutine_create(CoroutineEntry *entry) { Coroutine *co = NULL; if (CONFIG_COROUTINE_POOL) { - qemu_mutex_lock(&pool_lock); - co = QSLIST_FIRST(&pool); + co = QSLIST_FIRST(&alloc_pool); + if (!co) { + if (release_pool_size > POOL_BATCH_SIZE) { + /* Slow path; a good place to register the destructor, too. */ + if (!coroutine_pool_cleanup_notifier.notify) { + coroutine_pool_cleanup_notifier.notify = coroutine_pool_cleanup; + qemu_thread_atexit_add(&coroutine_pool_cleanup_notifier); + } + + /* This is not exact; there could be a little skew between + * release_pool_size and the actual size of release_pool. But + * it is just a heuristic, it does not need to be perfect. + */ + release_pool_size = 0; + QSLIST_MOVE_ATOMIC(&alloc_pool, &release_pool); + co = QSLIST_FIRST(&alloc_pool); + } + } if (co) { - QSLIST_REMOVE_HEAD(&pool, pool_next); - pool_size--; + QSLIST_REMOVE_HEAD(&alloc_pool, pool_next); } - qemu_mutex_unlock(&pool_lock); } if (!co) { @@ -53,39 +79,19 @@ Coroutine *qemu_coroutine_create(CoroutineEntry *entry) static void coroutine_delete(Coroutine *co) { + co->caller = NULL; + if (CONFIG_COROUTINE_POOL) { - qemu_mutex_lock(&pool_lock); - if (pool_size < pool_max_size) { - QSLIST_INSERT_HEAD(&pool, co, pool_next); - co->caller = NULL; - pool_size++; - qemu_mutex_unlock(&pool_lock); + if (release_pool_size < POOL_BATCH_SIZE * 2) { + QSLIST_INSERT_HEAD_ATOMIC(&release_pool, co, pool_next); + atomic_inc(&release_pool_size); return; } - qemu_mutex_unlock(&pool_lock); } qemu_coroutine_delete(co); } -static void __attribute__((constructor)) coroutine_pool_init(void) -{ - qemu_mutex_init(&pool_lock); -} - -static void __attribute__((destructor)) coroutine_pool_cleanup(void) -{ - Coroutine *co; - Coroutine *tmp; - - QSLIST_FOREACH_SAFE(co, &pool, pool_next, tmp) { - QSLIST_REMOVE_HEAD(&pool, pool_next); - qemu_coroutine_delete(co); - } - - qemu_mutex_destroy(&pool_lock); -} - static void coroutine_swap(Coroutine *from, Coroutine *to) { CoroutineAction ret; @@ -140,20 +146,4 @@ void coroutine_fn qemu_coroutine_yield(void) void qemu_coroutine_adjust_pool_size(int n) { - qemu_mutex_lock(&pool_lock); - - pool_max_size += n; - - /* Callers should never take away more than they added */ - assert(pool_max_size >= POOL_DEFAULT_SIZE); - - /* Trim oversized pool down to new max */ - while (pool_size > pool_max_size) { - Coroutine *co = QSLIST_FIRST(&pool); - QSLIST_REMOVE_HEAD(&pool, pool_next); - pool_size--; - qemu_coroutine_delete(co); - } - - qemu_mutex_unlock(&pool_lock); } |