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
next prev parent reply other threads:[~2009-05-09 16:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <49FDB9F8.3080400@free.fr>
[not found] ` <20090506133131F.fujita.tomonori@lab.ntt.co.jp>
[not found] ` <4A012FC8.3020304@free.fr>
2009-05-06 6:45 ` DMA debug trace pointing to rtl8187 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
2009-05-06 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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