From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx187.postini.com [74.125.245.187]) by kanga.kvack.org (Postfix) with SMTP id 687CC6B0044 for ; Thu, 23 Aug 2012 01:58:55 -0400 (EDT) Received: from epcpsbgm2.samsung.com (mailout3.samsung.com [203.254.224.33]) by mailout3.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0M9700M0F1X9MHQ0@mailout3.samsung.com> for linux-mm@kvack.org; Thu, 23 Aug 2012 14:58:53 +0900 (KST) Received: from AMDC159 ([106.116.147.30]) by mmp1.samsung.com (Oracle Communications Messaging Server 7u4-24.01 (7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0M9700LB31XOHH20@mmp1.samsung.com> for linux-mm@kvack.org; Thu, 23 Aug 2012 14:58:53 +0900 (KST) From: Marek Szyprowski References: <1345630830-9586-1-git-send-email-hdoyu@nvidia.com> <1345630830-9586-3-git-send-email-hdoyu@nvidia.com> <20120822.163648.3800987367886904.hdoyu@nvidia.com> In-reply-to: <20120822.163648.3800987367886904.hdoyu@nvidia.com> Subject: RE: [RFC 2/4] ARM: dma-mapping: IOMMU allocates pages from pool with GFP_ATOMIC Date: Thu, 23 Aug 2012 07:58:34 +0200 Message-id: <012401cd80f4$59727020$0c575060$%szyprowski@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit Content-language: pl Sender: owner-linux-mm@kvack.org List-ID: To: 'Hiroshi Doyu' , pullip.cho@samsung.com Cc: linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kyungmin.park@samsung.com, arnd@arndb.de, linux@arm.linux.org.uk, chunsang.jeong@linaro.org, 'Krishna Reddy' , konrad.wilk@oracle.com, subashrp@gmail.com, minchan@kernel.org Hello, On Wednesday, August 22, 2012 3:37 PM Hiroshi Doyu wrote: > KyongHo Cho wrote @ Wed, 22 Aug 2012 14:47:00 +0200: > > > vzalloc() call in __iommu_alloc_buffer() also causes BUG() in atomic context. > > Right. > > I've been thinking that kzalloc() may be enough here, since > vzalloc() was introduced to avoid allocation failure for big chunk of > memory, but I think that it's unlikely that the number of page array > can be so big. So I propose to drop vzalloc() here, and just simply to > use kzalloc only as below(*1). We already had a discussion about this, so I don't think it makes much sense to change it back to kzalloc. This vmalloc() call won't hurt anyone. It should not be considered a problem for atomic allocations, because no sane driver will try to allocate buffers larger than a dozen KiB with GFP_ATOMIC flag. I would call such try a serious bug, which we should not care here. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- 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