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[Qemu-devel] [PULL 29/62] thread-pool: avoid per-thread-pool EventNotifi
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PULL 29/62] thread-pool: avoid per-thread-pool EventNotifier |
Date: |
Fri, 8 Aug 2014 19:39:30 +0200 |
From: Stefan Hajnoczi <address@hidden>
EventNotifier is implemented using an eventfd or pipe. It therefore
consumes file descriptors, which can be limited by rlimits and should
therefore be used sparingly.
Switch from EventNotifier to QEMUBH in thread-pool.c. Originally
EventNotifier was used because qemu_bh_schedule() was not thread-safe
yet.
Reported-by: Christian Borntraeger <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
thread-pool.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
diff --git a/thread-pool.c b/thread-pool.c
index dfb699d..4cfd078 100644
--- a/thread-pool.c
+++ b/thread-pool.c
@@ -21,7 +21,6 @@
#include "block/coroutine.h"
#include "trace.h"
#include "block/block_int.h"
-#include "qemu/event_notifier.h"
#include "block/thread-pool.h"
#include "qemu/main-loop.h"
@@ -57,8 +56,8 @@ struct ThreadPoolElement {
};
struct ThreadPool {
- EventNotifier notifier;
AioContext *ctx;
+ QEMUBH *completion_bh;
QemuMutex lock;
QemuCond check_cancel;
QemuCond worker_stopped;
@@ -119,7 +118,7 @@ static void *worker_thread(void *opaque)
qemu_cond_broadcast(&pool->check_cancel);
}
- event_notifier_set(&pool->notifier);
+ qemu_bh_schedule(pool->completion_bh);
}
pool->cur_threads--;
@@ -168,12 +167,11 @@ static void spawn_thread(ThreadPool *pool)
}
}
-static void event_notifier_ready(EventNotifier *notifier)
+static void thread_pool_completion_bh(void *opaque)
{
- ThreadPool *pool = container_of(notifier, ThreadPool, notifier);
+ ThreadPool *pool = opaque;
ThreadPoolElement *elem, *next;
- event_notifier_test_and_clear(notifier);
restart:
QLIST_FOREACH_SAFE(elem, &pool->head, all, next) {
if (elem->state != THREAD_CANCELED && elem->state != THREAD_DONE) {
@@ -215,7 +213,7 @@ static void thread_pool_cancel(BlockDriverAIOCB *acb)
qemu_sem_timedwait(&pool->sem, 0) == 0) {
QTAILQ_REMOVE(&pool->request_list, elem, reqs);
elem->state = THREAD_CANCELED;
- event_notifier_set(&pool->notifier);
+ qemu_bh_schedule(pool->completion_bh);
} else {
pool->pending_cancellations++;
while (elem->state != THREAD_CANCELED && elem->state != THREAD_DONE) {
@@ -224,7 +222,7 @@ static void thread_pool_cancel(BlockDriverAIOCB *acb)
pool->pending_cancellations--;
}
qemu_mutex_unlock(&pool->lock);
- event_notifier_ready(&pool->notifier);
+ thread_pool_completion_bh(pool);
}
static const AIOCBInfo thread_pool_aiocb_info = {
@@ -293,8 +291,8 @@ static void thread_pool_init_one(ThreadPool *pool,
AioContext *ctx)
}
memset(pool, 0, sizeof(*pool));
- event_notifier_init(&pool->notifier, false);
pool->ctx = ctx;
+ pool->completion_bh = aio_bh_new(ctx, thread_pool_completion_bh, pool);
qemu_mutex_init(&pool->lock);
qemu_cond_init(&pool->check_cancel);
qemu_cond_init(&pool->worker_stopped);
@@ -304,8 +302,6 @@ static void thread_pool_init_one(ThreadPool *pool,
AioContext *ctx)
QLIST_INIT(&pool->head);
QTAILQ_INIT(&pool->request_list);
-
- aio_set_event_notifier(ctx, &pool->notifier, event_notifier_ready);
}
ThreadPool *thread_pool_new(AioContext *ctx)
@@ -339,11 +335,10 @@ void thread_pool_free(ThreadPool *pool)
qemu_mutex_unlock(&pool->lock);
- aio_set_event_notifier(pool->ctx, &pool->notifier, NULL);
+ qemu_bh_delete(pool->completion_bh);
qemu_sem_destroy(&pool->sem);
qemu_cond_destroy(&pool->check_cancel);
qemu_cond_destroy(&pool->worker_stopped);
qemu_mutex_destroy(&pool->lock);
- event_notifier_cleanup(&pool->notifier);
g_free(pool);
}
--
1.8.3.1
- [Qemu-devel] [PULL 19/62] qemu-iotests: Add data pattern in version3 VMDK sample image in 059, (continued)
- [Qemu-devel] [PULL 19/62] qemu-iotests: Add data pattern in version3 VMDK sample image in 059, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 21/62] qemu-img info: show nocow info, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 20/62] vmdk: Optimize cluster allocation, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 24/62] block/archipelago: Add support for creating images, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 23/62] block/archipelago: Implement bdrv_parse_filename(), Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 25/62] QMP: Add support for Archipelago, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 22/62] block: Support Archipelago as a QEMU block backend, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 26/62] qemu-iotests: add support for Archipelago protocol, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 27/62] coroutine: make pool size dynamic, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 28/62] block: bump coroutine pool size for drives, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 29/62] thread-pool: avoid per-thread-pool EventNotifier,
Kevin Wolf <=
- [Qemu-devel] [PULL 30/62] thread-pool: avoid deadlock in nested aio_poll() calls, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 31/62] block: vhdx - add error check, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 32/62] block: VHDX endian fixes, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 33/62] test-coroutine: add baseline test that times the cost of function calls, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 34/62] block: allow bdrv_unref() to be passed NULL pointers, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 36/62] block: use the standard 'ret' instead of 'result', Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 39/62] block: Introduce qemu_try_blockalign(), Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 37/62] block: vpc - use block layer ops in vpc_create, instead of posix calls, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 35/62] block: vdi - use block layer ops in vdi_create, instead of posix calls, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 41/62] bochs: Handle failure for potentially large allocations, Kevin Wolf, 2014/08/08