The commit is pushed to "branch-rh7-3.10.0-229.7.2.vz7.9.x-ovz" and will appear
at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.9.12
------>
commit 93edfd2e140d8525c2090ce6e526f303b6490e1c
Author: Tejun Heo <t...@kernel.org>
Date: Mon Nov 23 19:30:37 2015 +0400
ms/cfq-iosched: fix async oom queue handling
Async cfqq's (cfq_queue's) are shared across cfq_data. When
cfq_get_queue() obtains a new queue from cfq_find_alloc_queue(), it
stashes the pointer in cfq_data and reuses it from then on; however,
the function doesn't consider that cfq_find_alloc_queue() may return
the oom_cfqq under memory pressure and installs the returned queue
unconditionally.
If the oom_cfqq is installed as an async cfqq, cfq_set_request() will
continue calling cfq_get_queue() hoping to replace it with a proper
queue; however, cfq_get_queue() will keep returning the cached queue
for the slot - the oom_cfqq.
Fix it by skipping caching if the queue is the oom one.
Signed-off-by: Tejun Heo <t...@kernel.org>
Acked-by: Jeff Moyer <jmo...@redhat.com>
Cc: Vivek Goyal <vgo...@redhat.com>
Cc: Arianna Avanzini <avanzini.aria...@gmail.com>
Signed-off-by: Jens Axboe <ax...@fb.com>
https://jira.sw.ru/browse/PSBM-41334
(cherry picked from commit 95e5d6f62693f27d9011ec307eb32c6126314ea3)
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
block/cfq-iosched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index a4149c3..911baae 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3711,7 +3711,7 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct
cfq_io_cq *cic,
/*
* pin the queue now that it's allocated, scheduler exit will prune it
*/
- if (!is_sync) {
+ if (!is_sync && cfqq != &cfqd->oom_cfqq) {
cfqq->ref++;
*async_cfqq = cfqq;
}
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