From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758298AbaELN5Z (ORCPT ); Mon, 12 May 2014 09:57:25 -0400 Received: from qmta14.emeryville.ca.mail.comcast.net ([76.96.27.212]:38488 "EHLO qmta14.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758173AbaELN5Y (ORCPT ); Mon, 12 May 2014 09:57:24 -0400 Date: Mon, 12 May 2014 08:57:20 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Jianyu Zhan cc: akpm@linux-foundation.org, mhocko@suse.cz, hannes@cmpxchg.org, riel@redhat.com, minchan@kernel.org, zhangyanfei@cn.fujitsu.com, hanpt@linux.vnet.ibm.com, sasha.levin@oracle.com, oleg@redhat.com, fabf@skynet.be, mgorman@suse.de, aarcange@redhat.com, cldu@marvell.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: use a irq-safe __mod_zone_page_state in mlocked_vma_newpage() In-Reply-To: <1399652208-18987-1-git-send-email-nasa4836@gmail.com> Message-ID: References: <1399652208-18987-1-git-send-email-nasa4836@gmail.com> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 10 May 2014, Jianyu Zhan wrote: > mlocked_vma_newpage() is only called in fault path by > page_add_new_anon_rmap(), which is called on a *new* page. > And such page is initially only visible via the pagetables, and the > pte is locked while calling page_add_new_anon_rmap(), so we need not > use an irq-safe mod_zone_page_state() here, using a light-weight version > __mod_zone_page_state() would be OK. This has nothing to do with the safety of statistics operations that work on different data structures. Which leads to the conclusion that __mod_page_state cannot be used here.