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From: Shaohua Li <shli@kernel.org>
To: linux-kernel@vger.kernel.org, axboe@kernel.dk
Cc: kmo@daterainc.com
Subject: [patch 0/4 v2] blk-mq: use percpu_ida to manage tags
Date: Tue, 15 Oct 2013 09:05:00 +0800	[thread overview]
Message-ID: <20131015010500.435964635@kernel.org> (raw)

Hi,
blk-mq and percpu_ida use similar algorithm to manage tags. The difference
is when a cpu can't allocate tags, blk-mq will use ipi to purge remote cpu
cache, while percpu-ida directly purges remote cpu cache. In practice, the
percpu-ida approach is much faster when we can't allocate enough for percpu
cache.

This patch makes blk-mq use percpu_ida to manage tags, this avoids some
duplicate code and has better performance as I mentioned. To test the patches,
rebase blk-mq tree to latest kernel first.

The v2 patch updated some log descriptions, fixed one issue Kent pointed out
and added performance data.

Thanks,
Shaohua

             reply	other threads:[~2013-10-15  1:07 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-15  1:05 Shaohua Li [this message]
2013-10-15  1:05 ` [patch 1/4 v2] percpu_ida: make percpu_ida percpu size/batch configurable Shaohua Li
2013-10-15  1:05 ` [patch 2/4 v2] percpu_ida: add percpu_ida_for_each_free Shaohua Li
2013-10-15  1:05 ` [patch 3/4 v2] percpu_ida: add an API to return free tags Shaohua Li
2013-10-15  1:05 ` [patch 4/4 v2] blk-mq: switch to percpu-ida for tag management Shaohua Li
2013-10-15 15:16 ` [patch 0/4 v2] blk-mq: use percpu_ida to manage tags Jens Axboe

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