diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2017-06-05 14:38:58 +0200 |
|---|---|---|
| committer | Fam Zheng <famz@redhat.com> | 2017-06-16 07:55:00 +0800 |
| commit | 93001e9d87ae40e7569eb0ece0eb86d9c9582e41 (patch) | |
| tree | 5a1566507d01274c72ed7fa3cca5c845a3a7e8d5 | |
| parent | 3b170dc86732539ebc5927880097d32d4f11df8c (diff) | |
| download | qemu-93001e9d87ae40e7569eb0ece0eb86d9c9582e41.tar.gz | |
throttle-groups: protect throttled requests with a CoMutex
Another possibility is to use tg->lock, which we're holding anyway in
both schedule_next_request and throttle_group_co_io_limits_intercept.
This would require open-coding the CoQueue however, so I've chosen this
alternative.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170605123908.18777-10-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
| -rw-r--r-- | block/block-backend.c | 1 | ||||
| -rw-r--r-- | block/throttle-groups.c | 12 | ||||
| -rw-r--r-- | include/sysemu/block-backend.h | 7 |
3 files changed, 13 insertions, 7 deletions
diff --git a/block/block-backend.c b/block/block-backend.c index 69d0e11466..738882dd2e 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -216,6 +216,7 @@ BlockBackend *blk_new(uint64_t perm, uint64_t shared_perm) blk->shared_perm = shared_perm; blk_set_enable_write_cache(blk, true); + qemu_co_mutex_init(&blk->public.throttled_reqs_lock); qemu_co_queue_init(&blk->public.throttled_reqs[0]); qemu_co_queue_init(&blk->public.throttled_reqs[1]); diff --git a/block/throttle-groups.c b/block/throttle-groups.c index 8bf1031efa..a181cb1dee 100644 --- a/block/throttle-groups.c +++ b/block/throttle-groups.c @@ -270,8 +270,13 @@ static bool coroutine_fn throttle_group_co_restart_queue(BlockBackend *blk, bool is_write) { BlockBackendPublic *blkp = blk_get_public(blk); + bool ret; - return qemu_co_queue_next(&blkp->throttled_reqs[is_write]); + qemu_co_mutex_lock(&blkp->throttled_reqs_lock); + ret = qemu_co_queue_next(&blkp->throttled_reqs[is_write]); + qemu_co_mutex_unlock(&blkp->throttled_reqs_lock); + + return ret; } /* Look for the next pending I/O request and schedule it. @@ -340,7 +345,10 @@ void coroutine_fn throttle_group_co_io_limits_intercept(BlockBackend *blk, if (must_wait || blkp->pending_reqs[is_write]) { blkp->pending_reqs[is_write]++; qemu_mutex_unlock(&tg->lock); - qemu_co_queue_wait(&blkp->throttled_reqs[is_write], NULL); + qemu_co_mutex_lock(&blkp->throttled_reqs_lock); + qemu_co_queue_wait(&blkp->throttled_reqs[is_write], + &blkp->throttled_reqs_lock); + qemu_co_mutex_unlock(&blkp->throttled_reqs_lock); qemu_mutex_lock(&tg->lock); blkp->pending_reqs[is_write]--; } diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 24b63d6b03..999eb2333a 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -72,11 +72,8 @@ typedef struct BlockDevOps { * fields that must be public. This is in particular for QLIST_ENTRY() and * friends so that BlockBackends can be kept in lists outside block-backend.c */ typedef struct BlockBackendPublic { - /* I/O throttling has its own locking, but also some fields are - * protected by the AioContext lock. - */ - - /* Protected by AioContext lock. */ + /* throttled_reqs_lock protects the CoQueues for throttled requests. */ + CoMutex throttled_reqs_lock; CoQueue throttled_reqs[2]; /* Nonzero if the I/O limits are currently being ignored; generally |