linux-kernel - Re: [PATCH RFC 0/7] blk-mq: improve tag fair sharing

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: <dce8850c-92ee-8519-aa74-dc2d7ecc41e0@acm.org>
Date:   Thu, 6 Jul 2023 11:43:01 -0700
From:   Bart Van Assche <bvanassche@....org>
To:     Yu Kuai <yukuai1@...weicloud.com>, axboe@...nel.dk
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        yi.zhang@...wei.com, yangerkun@...wei.com,
        Christoph Hellwig <hch@....de>,
        "yukuai (C)" <yukuai3@...wei.com>
Subject: Re: [PATCH RFC 0/7] blk-mq: improve tag fair sharing

On 7/4/23 20:17, Yu Kuai wrote:
> - currently borrowed tags will never be returned untill queue is idle,
> I should figure out a way to return borrowed tags if this queue is not
> busy, so that other queues can borrow tag from this queue.

At least for UFS this is a significant disadvantage. If e.g. one SCSI
command is sent to the UFS WLUN every 20 seconds and the request queue
timeout is 30 seconds then borrowed tags will never be returned.

The complexity of this patch series is a concern to me. The complexity
of this patch series may be a barrier towards merging this patch series
in the upstream kernel.

Thanks,

Bart.