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From: Ming Lei <ming.lei@redhat.com>
To: Yu Kuai <yukuai1@huaweicloud.com>
Cc: bvanassche@acm.org, hch@lst.de, kbusch@kernel.org,
	axboe@kernel.dk, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, yukuai3@huawei.com,
	yi.zhang@huawei.com, yangerkun@huawei.com
Subject: Re: [PATCH RFC v2 0/8] blk-mq: improve tag fair sharing
Date: Mon, 23 Oct 2023 12:38:03 +0800	[thread overview]
Message-ID: <ZTX4q7QBerKbjzQA@fedora> (raw)
In-Reply-To: <20231021154806.4019417-1-yukuai1@huaweicloud.com>

Hello Yu Kuai,

On Sat, Oct 21, 2023 at 11:47:58PM +0800, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
> 
> Current implementation:
>  - a counter active_queues record how many queue/hctx is sharing tags,
>  and it's updated while issue new IO, and cleared in
>  blk_mq_timeout_work().
>  - if active_queues is more than 1, then tags is fair shared to each
>  node;

Can you explain a bit what the problem is in current tag sharing?
And what is your basic approach for this problem?

Just mentioning the implementation is not too helpful for initial
review, cause the problem and approach(correctness) need to be
understood first.

Thanks, 
Ming


  parent reply	other threads:[~2023-10-23  4:39 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-21 15:47 [PATCH RFC v2 0/8] blk-mq: improve tag fair sharing Yu Kuai
2023-10-21 15:47 ` [PATCH RFC v2 1/8] blk-mq: factor out a structure from blk_mq_tags Yu Kuai
2023-10-21 15:48 ` [PATCH RFC v2 2/8] blk-mq: factor out a structure to store information for tag sharing Yu Kuai
2023-10-21 15:48 ` [PATCH RFC v2 3/8] blk-mq: add a helper to initialize shared_tag_info Yu Kuai
2023-10-21 15:48 ` [PATCH RFC v2 4/8] blk-mq: support to track active queues from blk_mq_tags Yu Kuai
2023-10-21 15:48 ` [PATCH RFC v2 5/8] blk-mq: precalculate available tags for hctx_may_queue() Yu Kuai
2023-10-21 15:48 ` [PATCH RFC v2 6/8] blk-mq: add new helpers blk_mq_driver_tag_busy/idle() Yu Kuai
2023-10-21 15:48 ` [PATCH RFC v2 7/8] blk-mq-tag: delay tag sharing until fail to get driver tag Yu Kuai
2023-10-21 15:48 ` [PATCH RFC v2 8/8] blk-mq-tag: allow shared queue/hctx to get more driver tags Yu Kuai
2023-10-23 20:46   ` Bart Van Assche
2023-10-24  1:07     ` Yu Kuai
2023-10-23  4:38 ` Ming Lei [this message]
2023-10-23  7:26   ` [PATCH RFC v2 0/8] blk-mq: improve tag fair sharing Yu Kuai

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