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authorTejun Heo <tj@kernel.org>2015-08-18 14:54:58 -0700
committerJens Axboe <axboe@fb.com>2015-08-18 15:49:15 -0700
commit95e5d6f62693f27d9011ec307eb32c6126314ea3 (patch)
tree4b30989af492f003a7bdb9534951f47f5341273d /block
parent4ebc1c61d6185604c97fd0b0355ab668052044ab (diff)
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 <tj@kernel.org> Acked-by: Jeff Moyer <jmoyer@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Arianna Avanzini <avanzini.arianna@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
-rw-r--r--block/cfq-iosched.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index e91093d0c0eb..baf0b706169d 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3751,7 +3751,7 @@ 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;
}