archive mirror
 help / color / mirror / Atom feed
From: brookxu <>
To: Tejun Heo <>
Subject: Re: [PATCH v2] blk-throtl: optimize IOPS throttle for large IO scenarios
Date: Mon, 2 Aug 2021 09:30:29 +0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Tejun Heo wrote on 2021/7/31 12:07 上午:
> On Fri, Jul 30, 2021 at 10:09:34AM +0800, brookxu wrote:
>>>> @@ -877,10 +900,19 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw)
>>>>  	else
>>>>  		tg->bytes_disp[rw] = 0;
>>>> -	if (tg->io_disp[rw] >= io_trim)
>>>> +	if (tg_io_disp(tg, rw) >= io_trim) {
>>> Instead of checking this in multiple places, would it be simpler to transfer
>>> the atomic counters to the existing counters whenever we enter blk-throtl
>>> and leave the rest of the code as-is?
>> If we do this, we need to do similar processing on the bio submission path and the bio
>> resubmission path in pending_timer. It seems that the code is more complicated?
> Yeah, basically whenever we enter blk-throtl. Factored to a function,
> calling it on entry should be fairly clean, right? I wonder whether it'd be
> better to consolidate all atomic counter handling in a single location and
> all it does is transferring whatever's accumulated to the usual counters.
> Also, when you're reading & resetting the atomic counters, can you use a
> pattern like the following?
>   main_counter += atomic_xchg(counter, 0);
> Right now, there's a race window between reading and resetting.

Yeah, thanks for your suggestion, I will submit the next version later.

> Thanks.

      reply	other threads:[~2021-08-02  1:31 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-28  9:01 [PATCH v2] blk-throtl: optimize IOPS throttle for large IO scenarios brookxu
2021-07-29 17:11 ` Tejun Heo
2021-07-30  2:09   ` brookxu
2021-07-30 16:07     ` Tejun Heo
2021-08-02  1:30       ` brookxu [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).