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>
This commit is contained in:
Paolo Bonzini 2017-06-05 14:38:58 +02:00 committed by Fam Zheng
parent 3b170dc867
commit 93001e9d87
3 changed files with 13 additions and 7 deletions

View file

@ -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