diff options
Diffstat (limited to 'util')
| -rw-r--r-- | util/aio-posix.c | 1 | ||||
| -rw-r--r-- | util/async.c | 20 | ||||
| -rw-r--r-- | util/main-loop.c | 9 | ||||
| -rw-r--r-- | util/thread-pool.c | 55 |
4 files changed, 81 insertions, 4 deletions
diff --git a/util/aio-posix.c b/util/aio-posix.c index be0182a..731f382 100644 --- a/util/aio-posix.c +++ b/util/aio-posix.c @@ -15,6 +15,7 @@ #include "qemu/osdep.h" #include "block/block.h" +#include "block/thread-pool.h" #include "qemu/main-loop.h" #include "qemu/rcu.h" #include "qemu/rcu_queue.h" diff --git a/util/async.c b/util/async.c index 2ea1172..554ba70 100644 --- a/util/async.c +++ b/util/async.c @@ -563,6 +563,9 @@ AioContext *aio_context_new(Error **errp) ctx->aio_max_batch = 0; + ctx->thread_pool_min = 0; + ctx->thread_pool_max = THREAD_POOL_MAX_THREADS_DEFAULT; + return ctx; fail: g_source_destroy(&ctx->source); @@ -696,3 +699,20 @@ void qemu_set_current_aio_context(AioContext *ctx) assert(!get_my_aiocontext()); set_my_aiocontext(ctx); } + +void aio_context_set_thread_pool_params(AioContext *ctx, int64_t min, + int64_t max, Error **errp) +{ + + if (min > max || !max || min > INT_MAX || max > INT_MAX) { + error_setg(errp, "bad thread-pool-min/thread-pool-max values"); + return; + } + + ctx->thread_pool_min = min; + ctx->thread_pool_max = max; + + if (ctx->thread_pool) { + thread_pool_update_params(ctx->thread_pool, ctx); + } +} diff --git a/util/main-loop.c b/util/main-loop.c index e30f034..f00a254 100644 --- a/util/main-loop.c +++ b/util/main-loop.c @@ -30,6 +30,7 @@ #include "sysemu/replay.h" #include "qemu/main-loop.h" #include "block/aio.h" +#include "block/thread-pool.h" #include "qemu/error-report.h" #include "qemu/queue.h" #include "qemu/compiler.h" @@ -187,12 +188,20 @@ int qemu_init_main_loop(Error **errp) static void main_loop_update_params(EventLoopBase *base, Error **errp) { + ERRP_GUARD(); + if (!qemu_aio_context) { error_setg(errp, "qemu aio context not ready"); return; } aio_context_set_aio_params(qemu_aio_context, base->aio_max_batch, errp); + if (*errp) { + return; + } + + aio_context_set_thread_pool_params(qemu_aio_context, base->thread_pool_min, + base->thread_pool_max, errp); } MainLoop *mloop; diff --git a/util/thread-pool.c b/util/thread-pool.c index d763cea..196835b 100644 --- a/util/thread-pool.c +++ b/util/thread-pool.c @@ -58,7 +58,6 @@ struct ThreadPool { QemuMutex lock; QemuCond worker_stopped; QemuSemaphore sem; - int max_threads; QEMUBH *new_thread_bh; /* The following variables are only accessed from one AioContext. */ @@ -71,8 +70,27 @@ struct ThreadPool { int new_threads; /* backlog of threads we need to create */ int pending_threads; /* threads created but not running yet */ bool stopping; + int min_threads; + int max_threads; }; +static inline bool back_to_sleep(ThreadPool *pool, int ret) +{ + /* + * The semaphore timed out, we should exit the loop except when: + * - There is work to do, we raced with the signal. + * - The max threads threshold just changed, we raced with the signal. + * - The thread pool forces a minimum number of readily available threads. + */ + if (ret == -1 && (!QTAILQ_EMPTY(&pool->request_list) || + pool->cur_threads > pool->max_threads || + pool->cur_threads <= pool->min_threads)) { + return true; + } + + return false; +} + static void *worker_thread(void *opaque) { ThreadPool *pool = opaque; @@ -91,8 +109,9 @@ static void *worker_thread(void *opaque) ret = qemu_sem_timedwait(&pool->sem, 10000); qemu_mutex_lock(&pool->lock); pool->idle_threads--; - } while (ret == -1 && !QTAILQ_EMPTY(&pool->request_list)); - if (ret == -1 || pool->stopping) { + } while (back_to_sleep(pool, ret)); + if (ret == -1 || pool->stopping || + pool->cur_threads > pool->max_threads) { break; } @@ -294,6 +313,33 @@ void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, void *arg) thread_pool_submit_aio(pool, func, arg, NULL, NULL); } +void thread_pool_update_params(ThreadPool *pool, AioContext *ctx) +{ + qemu_mutex_lock(&pool->lock); + + pool->min_threads = ctx->thread_pool_min; + pool->max_threads = ctx->thread_pool_max; + + /* + * We either have to: + * - Increase the number available of threads until over the min_threads + * threshold. + * - Decrease the number of available threads until under the max_threads + * threshold. + * - Do nothing. The current number of threads fall in between the min and + * max thresholds. We'll let the pool manage itself. + */ + for (int i = pool->cur_threads; i < pool->min_threads; i++) { + spawn_thread(pool); + } + + for (int i = pool->cur_threads; i > pool->max_threads; i--) { + qemu_sem_post(&pool->sem); + } + + qemu_mutex_unlock(&pool->lock); +} + static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx) { if (!ctx) { @@ -306,11 +352,12 @@ static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx) qemu_mutex_init(&pool->lock); qemu_cond_init(&pool->worker_stopped); qemu_sem_init(&pool->sem, 0); - pool->max_threads = 64; pool->new_thread_bh = aio_bh_new(ctx, spawn_thread_bh_fn, pool); QLIST_INIT(&pool->head); QTAILQ_INIT(&pool->request_list); + + thread_pool_update_params(pool, ctx); } ThreadPool *thread_pool_new(AioContext *ctx) |