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[Qemu-devel] [PULL v3 13/23] throttle-groups: protect throttled requests
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PULL v3 13/23] throttle-groups: protect throttled requests with a CoMutex |
Date: |
Thu, 8 Jun 2017 19:56:33 +0800 |
From: Paolo Bonzini <address@hidden>
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 <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Fam Zheng <address@hidden>
---
block/block-backend.c | 1 +
block/throttle-groups.c | 12 ++++++++++--
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 e50ec03..be2ddf1 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 8bf1031..a181cb1 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 24b63d6..999eb23 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
--
2.9.4
- [Qemu-devel] [PULL v3 01/23] docker: Run tests with current user, (continued)
- [Qemu-devel] [PULL v3 01/23] docker: Run tests with current user, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 03/23] docker: Add libaio to fedora image, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 04/23] docker: Add flex and bison to centos6 image, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 05/23] block: access copy_on_read with atomic ops, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 07/23] block: access io_limits_disabled with atomic ops, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 06/23] block: access quiesce_counter with atomic ops, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 08/23] block: access serialising_in_flight with atomic ops, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 09/23] block: access wakeup with atomic ops, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 11/23] throttle-groups: only start one coroutine from drained_begin, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 12/23] throttle-groups: do not use qemu_co_enter_next, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 13/23] throttle-groups: protect throttled requests with a CoMutex,
Fam Zheng <=
- [Qemu-devel] [PULL v3 10/23] block: access io_plugged with atomic ops, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 14/23] util: add stats64 module, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 15/23] block: use Stat64 for wr_highest_offset, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 16/23] block: access write_gen with atomics, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 19/23] migration/block: reset dirty bitmap before reading, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 17/23] block: protect tracked_requests and flush_queue with reqs_lock, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 18/23] block: introduce dirty_bitmap_mutex, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 20/23] block: protect modification of dirty bitmaps with a mutex, Fam Zheng, 2017/06/08
- [Qemu-devel] [PULL v3 21/23] block: introduce block_account_one_io, Fam Zheng, 2017/06/08