From: Christoph Hellwig <hch@infradead.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: James Bottomley <jbottomley@parallels.com>,
Mike Christie <michaelc@cs.wisc.edu>,
Hannes Reinecke <hare@suse.de>,
David Milburn <dmilburn@redhat.com>,
linux-scsi <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH 7/7] Micro-optimize scsi_next_command()
Date: Sun, 1 Sep 2013 10:06:13 -0700 [thread overview]
Message-ID: <20130901170613.GF4344@infradead.org> (raw)
In-Reply-To: <52135CC1.3000901@acm.org>
On Tue, Aug 20, 2013 at 02:10:41PM +0200, Bart Van Assche wrote:
> Eliminate a get_device() / put_device() pair from scsi_next_command().
> Both are atomic operations hence removing these slightly improves
> performance.
The same should also be applied to scsi_requeue_command, while it might
not matter for performance it'll make the code a lot more readable,
especially when also merging scsi_unprep_request into
scsi_requeue_command. See the patch I'll send out for this ASAP.
I'm also not sure if there's a point in keeping the
get/_put_command_and_dev variants. There's very few callers left and
just opencoding the device reference manipulation might be cleaner.
next prev parent reply other threads:[~2013-09-01 17:06 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-20 12:05 SCSI core patches for kernel 3.12 Bart Van Assche
2013-08-20 12:06 ` [PATCH 1/7] Introduce scsi_device_being_removed() Bart Van Assche
2013-09-01 16:43 ` Christoph Hellwig
2013-08-20 12:07 ` [PATCH 2/7] Rework scsi_internal_device_unblock() Bart Van Assche
2013-09-01 16:44 ` Christoph Hellwig
2013-08-20 12:08 ` [PATCH 3/7] Avoid re-enabling I/O after the transport became offline Bart Van Assche
2013-09-01 16:46 ` Christoph Hellwig
2013-08-20 12:08 ` [PATCH 4/7] Disallow changing the device state via sysfs into "deleted" Bart Van Assche
2013-09-01 16:49 ` Christoph Hellwig
2013-09-02 18:59 ` Bart Van Assche
2013-09-02 19:06 ` Christoph Hellwig
2013-09-02 19:12 ` Bart Van Assche
2013-09-02 19:17 ` Christoph Hellwig
2013-08-20 12:09 ` [PATCH 5/7] Micro-optimize scsi_request_fn() Bart Van Assche
2013-09-01 16:50 ` Christoph Hellwig
2013-08-20 12:09 ` [PATCH 6/7] Rename scsi_get_command() and scsi_put_command() Bart Van Assche
2013-08-20 12:10 ` [PATCH 7/7] Micro-optimize scsi_next_command() Bart Van Assche
2013-09-01 17:06 ` Christoph Hellwig [this message]
2013-09-01 17:08 ` [PATCH 8/7] scsi: cleanup scsi_requeue_command Christoph Hellwig
2013-08-20 16:11 ` SCSI core patches for kernel 3.12 Nicholas A. Bellinger
2013-08-20 16:15 ` Bart Van Assche
2013-08-20 17:04 ` Nicholas A. Bellinger
2013-08-20 18:00 ` Bart Van Assche
2013-08-20 20:38 ` Nicholas A. Bellinger
2013-08-21 6:48 ` Christoph Hellwig
2013-08-21 7:35 ` Nicholas A. Bellinger
2013-10-02 7:40 ` Christoph Hellwig
2013-10-02 15:15 ` James Bottomley
2013-10-02 16:17 ` Christoph Hellwig
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