linux-kernel - Re: [PATCH v3 3/5] md/raid10: prevent unnecessary calls to wake

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <641c8be0-69f6-0ab5-b174-411352ed5f94@deltatee.com>
Date:   Fri, 16 Sep 2022 12:36:14 -0600
From:   Logan Gunthorpe <logang@...tatee.com>
To:     Yu Kuai <yukuai1@...weicloud.com>, song@...nel.org,
        guoqing.jiang@...ux.dev, pmenzel@...gen.mpg.de
Cc:     linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org,
        yukuai3@...wei.com, yi.zhang@...wei.com
Subject: Re: [PATCH v3 3/5] md/raid10: prevent unnecessary calls to wake_up()
 in fast path



On 2022-09-16 05:34, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@...wei.com>
> 
> Currently, wake_up() is called unconditionally in fast path such as
> raid10_make_request(), which will cause lock contention under high
> concurrency:
> 
> raid10_make_request
>  wake_up
>   __wake_up_common_lock
>    spin_lock_irqsave
> 
> Improve performance by only call wake_up() if waitqueue is not empty
> in allow_barrier() and raid10_make_request().
> 
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>

Reviewed-by: Logan Gunthorpe <logang@...tatee.com>