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From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: tj@kernel.org, axboe@kernel.dk
Cc: baolin.wang@linux.alibaba.com, baolin.wang7@gmail.com,
	linux-block@vger.kernel.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 3/4] blk-throttle: Avoid tracking latency if low limit is invalid
Date: Sun, 20 Sep 2020 17:14:26 +0800	[thread overview]
Message-ID: <a244c9973c6fc0081dba4142625840696b386a0f.1600592693.git.baolin.wang@linux.alibaba.com> (raw)
In-Reply-To: <cover.1600592693.git.baolin.wang@linux.alibaba.com>

The IO latency tracking is only for LOW limit, so we should add a
validation to avoid redundant latency tracking if the LOW limit
is not valid.

Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
---
 block/blk-throttle.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 7e72102..b0d8f7c 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -2100,7 +2100,7 @@ static void throtl_update_latency_buckets(struct throtl_data *td)
 	unsigned long last_latency[2] = { 0 };
 	unsigned long latency[2];
 
-	if (!blk_queue_nonrot(td->queue))
+	if (!blk_queue_nonrot(td->queue) || !td->limit_valid[LIMIT_LOW])
 		return;
 	if (time_before(jiffies, td->last_calculate_time + HZ))
 		return;
@@ -2338,6 +2338,8 @@ void blk_throtl_bio_endio(struct bio *bio)
 	if (!blkg)
 		return;
 	tg = blkg_to_tg(blkg);
+	if (!tg->td->limit_valid[LIMIT_LOW])
+		return;
 
 	finish_time_ns = ktime_get_ns();
 	tg->last_finish_time = finish_time_ns >> 10;
-- 
1.8.3.1


  parent reply	other threads:[~2020-09-20  9:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-20  9:10 [PATCH 0/4] Some improvements for blk throttle Baolin Wang
2020-09-20  9:10 ` [PATCH 1/4] blk-throttle: Remove a meaningless parameter for throtl_downgrade_state() Baolin Wang
2020-09-20  9:10 ` [PATCH 2/4] blk-throttle: Avoid getting the current time if tg->last_finish_time is 0 Baolin Wang
2020-09-20  9:14 ` Baolin Wang [this message]
2020-09-20  9:14 ` [PATCH 4/4] blk-throttle: Fix IO hang for a corner case Baolin Wang
2020-09-29 14:52 ` [PATCH 0/4] Some improvements for blk throttle Baolin Wang

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