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From: Greg KH <greg@kroah.com>
To: "John W. Linville" <linville@tuxdriver.com>
Cc: Eric Valette <eric.valette@free.fr>,
	Hin-Tak Leung <hintak.leung@gmail.com>,
	linux-wireless@vger.kernel.org,
	Larry Finger <Larry.Finger@lwfinger.net>,
	FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
	linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [RFT] rtl8187: use DMA-aware buffers with usb_control_msg
Date: Sat, 9 May 2009 09:35:23 -0700	[thread overview]
Message-ID: <20090509163523.GA1200@kroah.com> (raw)
In-Reply-To: <20090509155013.GA21763@tuxdriver.com>

On Sat, May 09, 2009 at 11:50:14AM -0400, John W. Linville wrote:
> > usb_control messages are slow and should not be on the "fast path" of
> > any data being sent through the device.  Any overhead of the
> > kmalloc/kfree is totally eaten up by the actual transmission turn around
> > time of the message itself, so you don't have to worry about the
> > performance impact.
> 
> Yeah, I don't like the original version either.  Even if the kmalloc's
> aren't a big performance hit, the failure path sucks.  I've included a
> new version below, but unfortunately I haven't had a chance to test it.
> Please give it a try if you get a chance?

Looks good to me, a bit cleaner even.

thanks,

greg k-h

  reply	other threads:[~2009-05-09 16:39 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-03 15:36 DMA debug trace pointing to rtl8187 Eric Valette
2009-05-06  4:30 ` FUJITA Tomonori
2009-05-06  5:21   ` Greg KH
2009-05-06  6:35   ` Eric Valette
2009-05-06  6:45     ` Greg KH
2009-05-06 18:02       ` [RFT] rtl8187: use DMA-aware buffers with usb_control_msg John W. Linville
2009-05-08 23:20         ` Hin-Tak Leung
2009-05-09  9:38           ` Eric Valette
2009-05-09 13:57             ` Greg KH
2009-05-09 15:50               ` John W. Linville
2009-05-09 16:35                 ` Greg KH [this message]
2009-05-09 21:24                 ` Larry Finger
2009-05-11 13:20                   ` John W. Linville
2009-05-11 22:23                     ` Hin-Tak Leung
2009-05-11 22:23                       ` Hin-Tak Leung
2009-05-06 18:03       ` DMA debug trace pointing to rtl8187 John W. Linville
2009-05-09 17:29       ` Larry Finger
2009-05-09 17:46         ` Eric Valette
2009-05-09 19:22           ` Eric Valette
2009-05-09 19:29         ` Greg KH
2009-05-09 20:19           ` Michael Buesch

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