From: Christoph Hellwig <hch@infradead.org>
To: Yu Kuai <yukuai3@huawei.com>
Cc: Ming Lei <ming.lei@redhat.com>,
axboe@kernel.dk, djeffery@redhat.com, bvanassche@acm.org,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
yi.zhang@huawei.com
Subject: Re: [PATCH -next] blk-mq: fix boot time regression for scsi drives with multiple hctx
Date: Tue, 14 Jun 2022 23:21:53 -0700 [thread overview]
Message-ID: <Yql6gbP2NmKsvFqH@infradead.org> (raw)
In-Reply-To: <01cb0e49-1154-33db-f572-3960c972fe08@huawei.com>
On Tue, Jun 14, 2022 at 09:15:36PM +0800, Yu Kuai wrote:
> > for making so long, so I guess there must be other delay added by the feature
> > of BLK_MQ_F_TAG_HCTX_SHARED.
>
> Please see details in the reasons 2), scsi scan will call
> __scsi_remove_device() a lot of times(each host, each channel, each
> target).
Well, if the SCSI core does that you are falling back to a sequentical
scan instad of using REPORT LUNS. Which seems like a bug on its own
that is worth investigation.
prev parent reply other threads:[~2022-06-15 6:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-14 7:14 [PATCH -next] blk-mq: fix boot time regression for scsi drives with multiple hctx Yu Kuai
2022-06-14 7:31 ` Ming Lei
2022-06-14 13:15 ` Yu Kuai
2022-06-14 14:26 ` Ming Lei
2022-06-15 6:21 ` Christoph Hellwig [this message]
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