Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753754Ab2KTTd2 (ORCPT ); Tue, 20 Nov 2012 14:33:28 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:38580 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752434Ab2KTTd0 (ORCPT ); Tue, 20 Nov 2012 14:33:26 -0500 Date: Tue, 20 Nov 2012 11:33:25 -0800 From: Andrew Morton To: Marek Szyprowski Cc: linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Kyungmin Park , Arnd Bergmann , Soren Moch , Thomas Petazzoni , Sebastian Hesselbarth , Andrew Lunn , Jason Cooper , KAMEZAWA Hiroyuki , Michal Hocko , Mel Gorman Subject: Re: [PATCH v2] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls Message-Id: <20121120113325.dde266ed.akpm@linux-foundation.org> In-Reply-To: <1353421905-3112-1-git-send-email-m.szyprowski@samsung.com> References: <20121119144826.f59667b2.akpm@linux-foundation.org> <1353421905-3112-1-git-send-email-m.szyprowski@samsung.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1067 Lines: 23 On Tue, 20 Nov 2012 15:31:45 +0100 Marek Szyprowski wrote: > dmapool always calls dma_alloc_coherent() with GFP_ATOMIC flag, > regardless the flags provided by the caller. This causes excessive > pruning of emergency memory pools without any good reason. Additionaly, > on ARM architecture any driver which is using dmapools will sooner or > later trigger the following error: > "ERROR: 256 KiB atomic DMA coherent pool is too small! > Please increase it with coherent_pool= kernel parameter!". > Increasing the coherent pool size usually doesn't help much and only > delays such error, because all GFP_ATOMIC DMA allocations are always > served from the special, very limited memory pool. > Is this problem serious enough to justify merging the patch into 3.7? And into -stable kernels? -- 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/