From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753506Ab1HZADH (ORCPT ); Thu, 25 Aug 2011 20:03:07 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:42214 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752188Ab1HZADE (ORCPT ); Thu, 25 Aug 2011 20:03:04 -0400 Date: Thu, 25 Aug 2011 17:03:02 -0700 From: Andrew Morton To: Akinobu Mita Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH -v2] debug-pagealloc: add support for highmem pages Message-Id: <20110825170302.81ed210c.akpm@linux-foundation.org> In-Reply-To: <1314281649-21508-1-git-send-email-akinobu.mita@gmail.com> References: <1314281649-21508-1-git-send-email-akinobu.mita@gmail.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 25 Aug 2011 23:14:09 +0900 Akinobu Mita wrote: > This adds support for highmem pages poisoning and verification to the > debug-pagealloc feature for no-architecture support. > Sorry, I had a brainfart. kmap_atomic() internally does the preempt_disable() (actually pagefault_disable()). --- a/mm/debug-pagealloc.c~debug-pagealloc-add-support-for-highmem-pages-fix +++ a/mm/debug-pagealloc.c @@ -23,14 +23,11 @@ static inline bool page_poison(struct pa static void poison_page(struct page *page) { - void *addr; + void *addr = kmap_atomic(page); - preempt_disable(); - addr = kmap_atomic(page); set_page_poison(page); memset(addr, PAGE_POISON, PAGE_SIZE); kunmap_atomic(addr); - preempt_enable(); } static void poison_pages(struct page *page, int n) @@ -82,12 +79,10 @@ static void unpoison_page(struct page *p if (!page_poison(page)) return; - preempt_disable(); addr = kmap_atomic(page); check_poison_mem(addr, PAGE_SIZE); clear_page_poison(page); kunmap_atomic(addr); - preempt_enable(); } static void unpoison_pages(struct page *page, int n) _