From: Jens Axboe <axboe@kernel.dk>
To: linux-block@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 3/3] blk-wbt: fix has-sleeper queueing check
Date: Tue, 21 Aug 2018 09:05:17 -0600 [thread overview]
Message-ID: <20180821150517.19744-4-axboe@kernel.dk> (raw)
In-Reply-To: <20180821150517.19744-1-axboe@kernel.dk>
We need to do this inside the loop as well, or we can allow new
IO to supersede previous IO.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
block/blk-wbt.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 853e22492f4e..c9358f1981fb 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -492,16 +492,17 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
{
struct rq_wait *rqw = get_rq_wait(rwb, wb_acct);
DECLARE_WAITQUEUE(wait, current);
+ bool has_sleeper;
- if (!wq_has_sleeper(&rqw->wait) &&
- rq_wait_inc_below(rqw, get_limit(rwb, rw)))
+ has_sleeper = wq_has_sleeper(&rqw->wait);
+ if (!has_sleeper && rq_wait_inc_below(rqw, get_limit(rwb, rw)))
return;
add_wait_queue_exclusive(&rqw->wait, &wait);
do {
set_current_state(TASK_UNINTERRUPTIBLE);
- if (rq_wait_inc_below(rqw, get_limit(rwb, rw)))
+ if (!has_sleeper && rq_wait_inc_below(rqw, get_limit(rwb, rw)))
break;
if (lock) {
@@ -510,6 +511,7 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
spin_lock_irq(lock);
} else
io_schedule();
+ has_sleeper = false;
} while (1);
__set_current_state(TASK_RUNNING);
--
2.17.1
prev parent reply other threads:[~2018-08-21 15:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-21 15:05 [PATCHSET 0/3] blk-wbt fixes Jens Axboe
2018-08-21 15:05 ` [PATCH 1/3] blk-wbt: move disable check into get_limit() Jens Axboe
2018-08-21 15:05 ` [PATCH 2/3] blk-wbt: use wq_has_sleeper() for wq active check Jens Axboe
2018-08-21 15:05 ` Jens Axboe [this message]
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