Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932464AbaLJQIe (ORCPT ); Wed, 10 Dec 2014 11:08:34 -0500 Received: from galahad.ideasonboard.com ([185.26.127.97]:41816 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932167AbaLJQIb (ORCPT ); Wed, 10 Dec 2014 11:08:31 -0500 From: Laurent Pinchart To: Vinod Koul , Simon Horman Cc: =?ISO-8859-1?Q?J=FCrg?= Billeter , Magnus Damm , Phil Edworthy , Kuninori Morimoto , linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org, dmaengine@vger.kernel.org Subject: Re: [PATCH] dmaengine: rcar-dmac: Handle hardware descriptor allocation failure Date: Wed, 10 Dec 2014 18:09:17 +0200 Message-ID: <2735456.CKbC358ZrM@avalon> User-Agent: KMail/4.12.5 (Linux/3.16.5-gentoo; KDE/4.12.5; x86_64; ; ) In-Reply-To: <20141209063912.GZ16827@intel.com> References: <1416924617-15939-1-git-send-email-j@bitron.ch> <20141208175044.GT16827@intel.com> <20141209063912.GZ16827@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Vinod, On Tuesday 09 December 2014 12:09:12 Vinod Koul wrote: > On Mon, Dec 08, 2014 at 11:20:44PM +0530, Vinod Koul wrote: > > On Mon, Dec 08, 2014 at 07:40:15PM +0200, Laurent Pinchart wrote: > > > > > [GIT PULL FOR v3.19] R-Car DMA engine driver > > > > > http://www.spinics.net/lists/linux-sh/msg37764.html > > > > > > > > And I dont seem to have this request in my Inbox :( > > > > Yes I do see it in archieves, so not sure how this is not present, not > > > > sure if the servers mangeled it!! > > > > > > I haven't CC'ed you, I'll make sure to do so next time. The mail should > > > still have reached you through the mailing list though (I assume you're > > > subscribed to dmaengine@vger.kernel.org ;-)). > > > > Yes I am, so should have reached me even though i wasnt cced > > I do see email reaching me from list without me being in CC, but then it > > wont hit my inbox and go to ML folder :) > > So generally its a good practice to CC relvant folks, lots of folks do ask > > that if ML is high volume > > Hey Laurent, > > I see that the oddity in commitlogs with change since artifacts after SOB, > can you please fix that up My bad. I've fixed the problem and pushed the result to the same branch git://linuxtv.org/pinchartl/fbdev.git dma/next The only difference lies in the commit logs. > commit 43dc9ba2b51ccb9124bf6fed614c5053500592a6 > Author: Laurent Pinchart > Date: Sat Jul 19 00:05:14 2014 +0200 > > dmaengine: rcar-dmac: Cache hardware descriptors memory > > Unlike DMA transfers descriptors that are preallocated and cached, > memory used to store hardware descriptors is allocated and freed with > the DMA coherent allocation API for every transfer. Besides degrading > performances, this creates a CMA stress test that seems to cause > issues. Running dmatest with the noverify option produces > > [ 50.066539] alloc_contig_range test_pages_isolated(6b845, 6b846) > failed [ 50.235180] alloc_contig_range test_pages_isolated(6b848, 6b84e) > failed [ 52.964584] alloc_contig_range test_pages_isolated(6b847, 6b848) > failed [ 54.127113] alloc_contig_range test_pages_isolated(6b843, 6b844) > failed [ 56.270253] alloc_contig_range test_pages_isolated(6b84c, 6b850) > failed > > The root cause needs to be fixed, but in the meantime, as a workaround > and a performance improvement, cache hardware descriptors. > > Signed-off-by: Laurent Pinchart > Tested-by: Wolfram Sang > > > --- > > Changes since v2: > > - Typo fixes > - Align allocated hwdesc size to page size > - Ignore allocated hwdesc memory when the transfer doesn't use hwdescs > > commit feb2e9f12b1a4a871b1d3eb2e2f44255510a79d3 > Author: Laurent Pinchart > Date: Wed Jul 16 23:15:48 2014 +0200 > > dmaengine: rcar-dmac: Implement support for hardware descriptor lists > > The DMAC supports hardware-based auto-configuration from descriptor > lists. This reduces the number of interrupts required for processing a > DMA transfer. Support that mode in the driver. > > Signed-off-by: Laurent Pinchart > Tested-by: Wolfram Sang > > > --- > > Changes since v2: > > - Typo fixes > - Use GFP_NOWAIT to allocate hardware descriptors > - Clear descriptor stage end interrupt when halting the channel > > and many more... -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/