From: Josef Bacik <josef@toxicpanda.com>
To: axboe@kernel.dk, kernel-team@fb.com, linux-block@vger.kernel.org,
peterz@infradead.org, oleg@redhat.com
Subject: [PATCH 3/5] rq-qos: don't reset has_sleepers on spurious wakeups
Date: Tue, 16 Jul 2019 16:19:27 -0400 [thread overview]
Message-ID: <20190716201929.79142-4-josef@toxicpanda.com> (raw)
In-Reply-To: <20190716201929.79142-1-josef@toxicpanda.com>
If we raced with somebody else getting an inflight counter we could fail
to get an inflight counter with no sleepers on the list, and thus need
to go to sleep. In this case has_sleepers should be true because we are
now relying on the waker to get our inflight counter for us. And in the
case of spurious wakeups we'd still want this to be the case. So set
has_sleepers to true if we went to sleep to make sure we're woken up the
proper way.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
block/blk-rq-qos.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c
index 67a0a4c07060..69a0f0b77795 100644
--- a/block/blk-rq-qos.c
+++ b/block/blk-rq-qos.c
@@ -261,7 +261,7 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data,
break;
}
io_schedule();
- has_sleeper = false;
+ has_sleeper = true;
} while (1);
finish_wait(&rqw->wait, &data.wq);
}
--
2.17.1
next prev parent reply other threads:[~2019-07-16 20:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-16 20:19 [PATCH 0/5][v3] rq-qos memory barrier shenanigans Josef Bacik
2019-07-16 20:19 ` [PATCH 1/5] wait: add wq_has_single_sleeper helper Josef Bacik
2019-07-16 20:19 ` [PATCH 2/5] rq-qos: fix missed wake-ups in rq_qos_throttle Josef Bacik
2019-07-16 20:19 ` Josef Bacik [this message]
2019-07-16 20:19 ` [PATCH 4/5] rq-qos: set ourself TASK_UNINTERRUPTIBLE after we schedule Josef Bacik
2019-07-16 20:19 ` [PATCH 5/5] rq-qos: use a mb for got_token Josef Bacik
2019-07-18 15:56 ` [PATCH 0/5][v3] rq-qos memory barrier shenanigans Oleg Nesterov
2019-07-18 16:20 ` Jens Axboe
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