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From: Jeff Garzik <jgarzik@pobox.com>
To: Lin Ming <ming.m.lin@intel.com>
Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org,
	Tejun Heo <tj@kernel.org>, "Rafael J. Wysocki" <rjw@sisk.pl>,
	Priyanka Gupta <ankaguptaca@gmail.com>,
	Zhang Rui <rui.zhang@intel.com>,
	"Huang, Ying" <ying.huang@intel.com>
Subject: Re: [RFC] ata port runtime pm
Date: Thu, 27 Oct 2011 23:37:54 -0400	[thread overview]
Message-ID: <4EAA2392.40105@pobox.com> (raw)
In-Reply-To: <1319772072.24236.0.camel@minggr>

On 10/27/2011 11:21 PM, Lin Ming wrote:
> @@ -3208,6 +3209,11 @@ int ata_scsi_queuecmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
>
>   	ap = ata_shost_to_port(shost);
>
> +	if (pm_runtime_suspended(&ap->tdev))
> +		pm_runtime_resume(&ap->tdev);
> +	pm_runtime_mark_last_busy(&ap->tdev);
> +	pm_request_autosuspend(&ap->tdev);
> +
>   	spin_lock_irqsave(ap->lock, irq_flags);
>


Putting this into the core command dispatch fast-path is rather 
disappointing.  That's at least one additional lock, plus some atomic 
instructions and tests.

	Jeff



  reply	other threads:[~2011-10-28  3:37 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-28  3:21 [RFC] ata port runtime pm Lin Ming
2011-10-28  3:37 ` Jeff Garzik [this message]
2011-10-28  5:36   ` Lin Ming
2011-10-28 17:31     ` Rafael J. Wysocki
2011-10-28 18:51       ` Alan Stern
2011-11-01  8:12         ` Lin Ming
2011-11-01 19:34           ` Alan Stern
  -- strict thread matches above, loose matches on Subject: below --
2011-10-28  3:20 Lin Ming

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