From mboxrd@z Thu Jan 1 00:00:00 1970 From: Akinobu Mita Subject: [PATCH -mm 2/2] x86: avoid duplicated memset in dma_generic_alloc_coherent() Date: Sun, 20 Apr 2014 21:39:47 +0900 Message-ID: <1397997587-11021-3-git-send-email-akinobu.mita@gmail.com> References: <1397997587-11021-1-git-send-email-akinobu.mita@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1397997587-11021-1-git-send-email-akinobu.mita-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org Cc: Andi Kleen , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, Akinobu Mita , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , David Woodhouse List-Id: iommu@lists.linux-foundation.org This patch fixes duplicated memset that is introduced by the patch x86-make-dma_alloc_coherent-return-zeroed-memory-if-cma-is-enabled.patch in -mm tree, and this change should be folded into it. If dma_generic_alloc_coherent() is called with __GFP_ZERO, it does a duplicated memset to the memory area allocated by alloc_pages_node() with __GFP_ZERO. This change fixes that inefficiency by clearing __GFP_ZERO bit in gfp flages before calling alloc_pages_node(). Note that dma_generic_alloc_coherent() always returns zeroed memory. Signed-off-by: Akinobu Mita Cc: Marek Szyprowski Cc: Konrad Rzeszutek Wilk Cc: David Woodhouse Cc: Don Dutile Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Andi Kleen Cc: x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org --- arch/x86/kernel/pci-dma.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index f15bf8d..a25e202 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -97,6 +97,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size, dma_mask = dma_alloc_coherent_mask(dev, flag); + flag &= ~__GFP_ZERO; again: page = NULL; /* CMA can be used only in the context which permits sleeping */ -- 1.8.3.2