From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757153AbaEIQRB (ORCPT ); Fri, 9 May 2014 12:17:01 -0400 Received: from mail-pa0-f50.google.com ([209.85.220.50]:53751 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757132AbaEIQQ6 (ORCPT ); Fri, 9 May 2014 12:16:58 -0400 From: Jianyu Zhan To: cl@linux.com, 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, nasa4836@gmail.com Cc: 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() Date: Sat, 10 May 2014 00:16:48 +0800 Message-Id: <1399652208-18987-1-git-send-email-nasa4836@gmail.com> X-Mailer: git-send-email 2.0.0-rc1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >You are changing from the irq safe variant to __mod_zone_page_state which >is *not* irq safe. Its legit to do so since presumably irqs are disabled >anyways so you do not have to worry about irq safeness of >__mod_zone_page_state. >Please update the description. Its a bit confusing right now. Hi, Christoph, I'm sorry for the misleading phrasing. Would be this one OK? Thanks. --------<8--------- mm: use a light-weight __mod_zone_page_state in mlocked_vma_newpage() 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. Signed-off-by: Jianyu Zhan --- mm/internal.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/internal.h b/mm/internal.h index 07b6736..69079b1 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -196,7 +196,7 @@ static inline int mlocked_vma_newpage(struct vm_area_struct *vma, return 0; if (!TestSetPageMlocked(page)) { - mod_zone_page_state(page_zone(page), NR_MLOCK, + __mod_zone_page_state(page_zone(page), NR_MLOCK, hpage_nr_pages(page)); count_vm_event(UNEVICTABLE_PGMLOCKED); } -- 2.0.0-rc1