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From: Christoph Hellwig <hch@infradead.org>
To: Kashyap Desai <kashyap.desai@avagotech.com>
Cc: Bart Van Assche <bvanassche@acm.org>,
	linux-scsi@vger.kernel.org, aacraid@adaptec.com, Elliott@hp.com,
	jbottomley@parallels.com, hch@infradead.org
Subject: Re: [PATCH] scsi.mq:Added enable_cmd_list flags in hostt to reduce lock contention
Date: Wed, 20 Aug 2014 05:41:15 -0700	[thread overview]
Message-ID: <20140820124115.GA15231@infradead.org> (raw)
In-Reply-To: <7932bf422121b7f7d23545abdc0065c8@mail.gmail.com>

On Wed, Aug 20, 2014 at 06:08:37PM +0530, Kashyap Desai wrote:
> > This code is in the hot path which means that caching "enable_cmd_list"
> > in struct Scsi_Host (as is done for many other SCSI host parameters)
> > probably
> > will (slightly) improve performance further. Otherwise this patch looks
> > fine to
> > me.
> I will send updated patch which will cache host template field
> "enable_cmd_list" for faster access in Scsi Host.

Thanks.  It might be worth to only set in in the host in fact.

Also please just remove the code about lock contention in
scsi_mq_prep_fn - the XXX really doesn't apply anymore and I think the
code should be self-explaining enough to not need a comment.

Otherwise the patch looks good to me.


  reply	other threads:[~2014-08-20 12:41 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-19 18:17 [PATCH] scsi.mq:Added enable_cmd_list flags in hostt to reduce lock contention Kashyap.Desai
2014-08-20 10:48 ` Bart Van Assche
2014-08-20 12:38   ` Kashyap Desai
2014-08-20 12:41     ` Christoph Hellwig [this message]
2014-08-20 12:46       ` Kashyap Desai

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