From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx184.postini.com [74.125.245.184]) by kanga.kvack.org (Postfix) with SMTP id 7DE9A6B0044 for ; Tue, 15 Jan 2013 12:49:26 -0500 (EST) Received: by mail-pb0-f54.google.com with SMTP id wz12so180301pbc.13 for ; Tue, 15 Jan 2013 09:49:25 -0800 (PST) Date: Tue, 15 Jan 2013 09:50:20 -0800 From: Greg KH Subject: Re: [PATCH v2] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls Message-ID: <20130115175020.GA3764@kroah.com> References: <20121119144826.f59667b2.akpm@linux-foundation.org> <1353421905-3112-1-git-send-email-m.szyprowski@samsung.com> <50F3F289.3090402@web.de> <20130115165642.GA25500@titan.lakedaemon.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130115165642.GA25500@titan.lakedaemon.net> Sender: owner-linux-mm@kvack.org List-ID: To: Jason Cooper Cc: Soeren Moch , Marek Szyprowski , Thomas Petazzoni , Andrew Lunn , Arnd Bergmann , Michal Hocko , linux-kernel@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, Kyungmin Park , KAMEZAWA Hiroyuki , Andrew Morton , Mel Gorman , linux-arm-kernel@lists.infradead.org, Sebastian Hesselbarth On Tue, Jan 15, 2013 at 11:56:42AM -0500, Jason Cooper wrote: > Greg, > > I've added you to the this thread hoping for a little insight into USB > drivers and their use of coherent and GFP_ATOMIC. Am I barking up the > wrong tree by looking a the drivers? I don't understand, which drivers are you referring to? USB host controller drivers, or the "normal" drivers? Most USB drivers use GFP_ATOMIC if they are creating memory during their URB callback path, as that is interrupt context. But it shouldn't be all that bad, and the USB core hasn't changed in a while, so something else must be causing this. greg k-h -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org