linux-kernel - Re: [PATCH v2] blk-throttle: fix lower bps rate by throtl_trim

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Message-Id: <174121710777.165456.10255728984898278903.b4-ty@kernel.dk>
Date: Wed, 05 Mar 2025 16:25:07 -0700
From: Jens Axboe <axboe@...nel.dk>
To: ming.lei@...hat.com, tj@...nel.org, josef@...icpanda.com, 
 vgoyal@...hat.com, Yu Kuai <yukuai1@...weicloud.com>
Cc: cgroups@...r.kernel.org, linux-block@...r.kernel.org, 
 linux-kernel@...r.kernel.org, yukuai3@...wei.com, yi.zhang@...wei.com, 
 yangerkun@...wei.com
Subject: Re: [PATCH v2] blk-throttle: fix lower bps rate by
 throtl_trim_slice()


On Thu, 27 Feb 2025 20:06:45 +0800, Yu Kuai wrote:
> The bio submission time may be a few jiffies more than the expected
> waiting time, due to 'extra_bytes' can't be divided in
> tg_within_bps_limit(), and also due to timer wakeup delay.
> In this case, adjust slice_start to jiffies will discard the extra wait time,
> causing lower rate than expected.
> 
> Current in-tree code already covers deviation by rounddown(), but turns
> out it is not enough, because jiffies - slice_start can be a multiple of
> throtl_slice.
> 
> [...]

Applied, thanks!

[1/1] blk-throttle: fix lower bps rate by throtl_trim_slice()
      commit: 29cb955934302a5da525db6b327c795572538426

Best regards,
-- 
Jens Axboe