From: Tejun Heo <tj@kernel.org>
To: Shaohua Li <shli@fb.com>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, axboe@fb.com, vgoyal@redhat.com
Subject: Re: [PATCH V5 05/17] blk-throttle: add upgrade logic for LIMIT_LOW state
Date: Mon, 9 Jan 2017 14:46:00 -0500 [thread overview]
Message-ID: <20170109194600.GI12827@mtj.duckdns.org> (raw)
In-Reply-To: <20170109184053.GG12827@mtj.duckdns.org>
Hello, again.
On Mon, Jan 09, 2017 at 01:40:53PM -0500, Tejun Heo wrote:
> I think it'd be great to explain the above. It was a bit difficult
> for me to follow. It's also interesting because we're tying state
> transitions for both read and write together. blk-throtl has been
> handling reads and writes independently, now the mode switching from
> low to max is shared across reads and writes. I suppose it could be
> fine but would it be complex to separate them out? It's weird to make
> this one state shared across reads and writes while not for others or
> was this sharing intentional?
I thought more about it and as the low limit is regulated by latency,
it makes sense to make the state shared across reads and writes;
otherwise, IOs in one direction could easily mess up the other
direction. Can you please document that this is an intentional design
and explain the rationale tho?
Thanks.
--
tejun
next prev parent reply other threads:[~2017-01-09 19:46 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-15 20:32 [PATCH V5 00/17] blk-throttle: add .low limit Shaohua Li
2016-12-15 20:32 ` [PATCH V5 01/17] blk-throttle: use U64_MAX/UINT_MAX to replace -1 Shaohua Li
2016-12-15 20:32 ` [PATCH V5 02/17] blk-throttle: prepare support multiple limits Shaohua Li
2016-12-15 20:32 ` [PATCH V5 03/17] blk-throttle: add .low interface Shaohua Li
2017-01-09 16:35 ` Tejun Heo
2016-12-15 20:32 ` [PATCH V5 04/17] blk-throttle: configure bps/iops limit for cgroup in low limit Shaohua Li
2017-01-09 17:35 ` Tejun Heo
2016-12-15 20:32 ` [PATCH V5 05/17] blk-throttle: add upgrade logic for LIMIT_LOW state Shaohua Li
2017-01-09 18:40 ` Tejun Heo
2017-01-09 19:46 ` Tejun Heo [this message]
2016-12-15 20:32 ` [PATCH V5 06/17] blk-throttle: add downgrade logic Shaohua Li
2016-12-15 20:32 ` [PATCH V5 07/17] blk-throttle: make sure expire time isn't too big Shaohua Li
2017-01-09 19:54 ` Tejun Heo
2016-12-15 20:32 ` [PATCH V5 08/17] blk-throttle: make throtl_slice tunable Shaohua Li
2017-01-09 20:08 ` Tejun Heo
2016-12-15 20:33 ` [PATCH V5 09/17] blk-throttle: detect completed idle cgroup Shaohua Li
2017-01-09 20:13 ` Tejun Heo
2016-12-15 20:33 ` [PATCH V5 10/17] blk-throttle: make bandwidth change smooth Shaohua Li
2017-01-09 20:28 ` Tejun Heo
2016-12-15 20:33 ` [PATCH V5 11/17] blk-throttle: add a simple idle detection Shaohua Li
2017-01-09 20:56 ` Tejun Heo
2016-12-15 20:33 ` [PATCH V5 12/17] blk-throttle: add interface to configure idle time threshold Shaohua Li
2017-01-09 20:58 ` Tejun Heo
2016-12-15 20:33 ` [PATCH V5 13/17] blk-throttle: ignore idle cgroup limit Shaohua Li
2017-01-09 21:01 ` Tejun Heo
2016-12-15 20:33 ` [PATCH V5 14/17] blk-throttle: add interface for per-cgroup target latency Shaohua Li
2017-01-09 21:14 ` Tejun Heo
2016-12-15 20:33 ` [PATCH V5 15/17] block: track request size in blk_issue_stat Shaohua Li
2016-12-16 2:01 ` kbuild test robot
2017-01-09 21:17 ` Tejun Heo
2016-12-15 20:33 ` [PATCH V5 16/17] blk-throttle: add a mechanism to estimate IO latency Shaohua Li
2017-01-09 21:39 ` Tejun Heo
2016-12-15 20:33 ` [PATCH V5 17/17] blk-throttle: add latency target support Shaohua Li
2017-01-09 21:46 ` [PATCH V5 00/17] blk-throttle: add .low limit Tejun Heo
2017-01-09 22:27 ` Shaohua Li
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