From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f174.google.com (mail-pd0-f174.google.com [209.85.192.174]) by kanga.kvack.org (Postfix) with ESMTP id B2DEB6B0253 for ; Fri, 31 Jul 2015 15:38:57 -0400 (EDT) Received: by pdrg1 with SMTP id g1so47434956pdr.2 for ; Fri, 31 Jul 2015 12:38:57 -0700 (PDT) Received: from mga14.intel.com (mga14.intel.com. [192.55.52.115]) by mx.google.com with ESMTP id i3si12383960pdp.75.2015.07.31.12.38.55 for ; Fri, 31 Jul 2015 12:38:56 -0700 (PDT) From: "Sean O. Stalley" Subject: [PATCH v2 0/4] mm: add dma_pool_zalloc() & pci_pool_zalloc() Date: Fri, 31 Jul 2015 12:36:40 -0700 Message-Id: <1438371404-3219-1-git-send-email-sean.stalley@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: corbet@lwn.net, vinod.koul@intel.com, bhelgaas@google.com, Julia.Lawall@lip6.fr, Gilles.Muller@lip6.fr, nicolas.palix@imag.fr, mmarek@suse.cz, akpm@linux-foundation.org Cc: sean.stalley@intel.com, bigeasy@linutronix.de, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, cocci@systeme.lip6.fr Currently a call to dma_pool_alloc() with a ___GFP_ZERO flag returns a non-zeroed memory region. This patchset adds support for the __GFP_ZERO flag to dma_pool_alloc(), adds 2 wrapper functions for allocing zeroed memory from a pool, and provides a coccinelle script for finding & replacing instances of dma_pool_alloc() followed by memset(0) with a single dma_pool_zalloc() call. Changes from v1 to v2: - don't memset() POOL_POISON_ALLOCATED in dma_pool_alloc() if __GFP_ZERO is set - Ran test to see how often pool_alloc_page() is called There was some concern that this always calls memset() to zero, instead of passing __GFP_ZERO into the page allocator. [https://lkml.org/lkml/2015/7/15/881] I ran a test on my system to get an idea of how often dma_pool_alloc() calls into pool_alloc_page(). After Boot: [ 30.119863] alloc_calls:541, page_allocs:7 After an hour: [ 3600.951031] alloc_calls:9566, page_allocs:12 After copying 1GB file onto a USB drive: [ 4260.657148] alloc_calls:17225, page_allocs:12 It doesn't look like dma_pool_alloc() calls down to the page allocator very often (at least on my system). Sean O. Stalley (4): mm: Add support for __GFP_ZERO flag to dma_pool_alloc() mm: Add dma_pool_zalloc() call to DMA API pci: mm: Add pci_pool_zalloc() call coccinelle: mm: scripts/coccinelle/api/alloc/pool_zalloc-simple.cocci Documentation/DMA-API.txt | 7 ++ include/linux/dmapool.h | 6 ++ include/linux/pci.h | 2 + mm/dmapool.c | 9 ++- .../coccinelle/api/alloc/pool_zalloc-simple.cocci | 84 ++++++++++++++++++++++ 5 files changed, 106 insertions(+), 2 deletions(-) create mode 100644 scripts/coccinelle/api/alloc/pool_zalloc-simple.cocci -- 1.9.1 -- 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