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From: Jan Kara <jack@suse.cz>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: <linux-block@vger.kernel.org>, Jens Axboe <axboe@kernel.dk>,
	Jan Kara <jack@suse.cz>
Subject: [PATCH 2/4] bfq: Allow current waker to defend against a tentative one
Date: Thu, 19 May 2022 12:52:30 +0200	[thread overview]
Message-ID: <20220519105235.31397-2-jack@suse.cz> (raw)
In-Reply-To: <20220519104621.15456-1-jack@suse.cz>

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@suse.cz>
---
 block/bfq-iosched.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 397f6be3c8fe..1cc242c90fb6 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2127,8 +2127,7 @@ 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;
 
 	/*
-- 
2.35.3


  parent reply	other threads:[~2022-05-19 10:52 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-19 10:52 [PATCH 0/4] bfq: Improve waker detection Jan Kara
2022-05-19 10:52 ` [PATCH 1/4] bfq: Relax waker detection for shared queues Jan Kara
2022-05-19 10:52 ` Jan Kara [this message]
2022-05-19 10:52 ` [PATCH 3/4] bfq: Remove superfluous conversion from RQ_BIC() Jan Kara
2022-05-19 10:52 ` [PATCH 4/4] bfq: Remove bfq_requeue_request_body() Jan Kara
2022-05-19 12:52 ` [PATCH 0/4] bfq: Improve waker detection Jens Axboe

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