diff options
| -rw-r--r-- | include/block/coroutine.h | 11 | ||||
| -rw-r--r-- | qemu-coroutine.c | 26 |
2 files changed, 34 insertions, 3 deletions
diff --git a/include/block/coroutine.h b/include/block/coroutine.h index b408f96b82..b9b7f488c9 100644 --- a/include/block/coroutine.h +++ b/include/block/coroutine.h @@ -223,4 +223,15 @@ void coroutine_fn co_aio_sleep_ns(AioContext *ctx, QEMUClockType type, * Note that this function clobbers the handlers for the file descriptor. */ void coroutine_fn yield_until_fd_readable(int fd); + +/** + * Add or subtract from the coroutine pool size + * + * The coroutine implementation keeps a pool of coroutines to be reused by + * qemu_coroutine_create(). This makes coroutine creation cheap. Heavy + * coroutine users should call this to reserve pool space. Call it again with + * a negative number to release pool space. + */ +void qemu_coroutine_adjust_pool_size(int n); + #endif /* QEMU_COROUTINE_H */ diff --git a/qemu-coroutine.c b/qemu-coroutine.c index 470852100a..bd574aa1b5 100644 --- a/qemu-coroutine.c +++ b/qemu-coroutine.c @@ -19,14 +19,14 @@ #include "block/coroutine_int.h" enum { - /* Maximum free pool size prevents holding too many freed coroutines */ - POOL_MAX_SIZE = 64, + POOL_DEFAULT_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; Coroutine *qemu_coroutine_create(CoroutineEntry *entry) { @@ -55,7 +55,7 @@ static void coroutine_delete(Coroutine *co) { if (CONFIG_COROUTINE_POOL) { qemu_mutex_lock(&pool_lock); - if (pool_size < POOL_MAX_SIZE) { + if (pool_size < pool_max_size) { QSLIST_INSERT_HEAD(&pool, co, pool_next); co->caller = NULL; pool_size++; @@ -137,3 +137,23 @@ void coroutine_fn qemu_coroutine_yield(void) self->caller = NULL; coroutine_swap(self, to); } + +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); +} |