This is a note to let you know that I've just added the patch titled
bfq: Allow current waker to defend against a tentative one
to the 5.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bfq-allow-current-waker-to-defend-against-a-tentativ.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 218f03acf0c8a414a29bd135b020d753d91a5a4c
Author: Jan Kara <jack@xxxxxxx>
Date: Thu May 19 12:52:30 2022 +0200
bfq: Allow current waker to defend against a tentative one
[ Upstream commit c5ac56bb6110e42e79d3106866658376b2e48ab9 ]
The code in bfq_check_waker() ignores wake up events from the current
waker. This makes it more likely we select a new tentative waker
although the current one is generating more wake up events. Treat
current waker the same way as any other process and allow it to reset
the waker detection logic.
Fixes: 71217df39dc6 ("block, bfq: make waker-queue detection more robust")
Signed-off-by: Jan Kara <jack@xxxxxxx>
Link: https://lore.kernel.org/r/20220519105235.31397-2-jack@xxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index e1c86f66400e..269ff82091cc 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2133,8 +2133,7 @@ static void bfq_check_waker(struct bfq_data *bfqd, struct bfq_queue *bfqq,
if (!bfqd->last_completed_rq_bfqq ||
bfqd->last_completed_rq_bfqq == bfqq ||
bfq_bfqq_has_short_ttime(bfqq) ||
- now_ns - bfqd->last_completion >= 4 * NSEC_PER_MSEC ||
- bfqd->last_completed_rq_bfqq == bfqq->waker_bfqq)
+ now_ns - bfqd->last_completion >= 4 * NSEC_PER_MSEC)
return;
/*
