From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx179.postini.com [74.125.245.179]) by kanga.kvack.org (Postfix) with SMTP id 231676B0037 for ; Sat, 16 Mar 2013 13:48:21 -0400 (EDT) Received: by mail-pb0-f42.google.com with SMTP id xb4so5142853pbc.29 for ; Sat, 16 Mar 2013 10:48:20 -0700 (PDT) Message-ID: <5144B05E.9040307@gmail.com> Date: Sun, 17 Mar 2013 01:48:14 +0800 From: Jiang Liu MIME-Version: 1.0 Subject: Re: [PATCH v2, part3 01/12] mm: enhance free_reserved_area() to support poisoning memory with zero References: <1363453413-8139-1-git-send-email-jiang.liu@huawei.com> <1363453413-8139-2-git-send-email-jiang.liu@huawei.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Geert Uytterhoeven Cc: Andrew Morton , David Rientjes , Jiang Liu , Wen Congyang , Mel Gorman , Minchan Kim , KAMEZAWA Hiroyuki , Michal Hocko , Jianguo Wu , linux-mm@kvack.org, linux-kernel@vger.kernel.org On 03/17/2013 01:37 AM, Geert Uytterhoeven wrote: > On Sat, Mar 16, 2013 at 6:03 PM, Jiang Liu wrote: >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -5130,13 +5130,13 @@ unsigned long free_reserved_area(unsigned long start, unsigned long end, >> pos = start = PAGE_ALIGN(start); >> end &= PAGE_MASK; >> for (pages = 0; pos < end; pos += PAGE_SIZE, pages++) { >> - if (poison) >> + if ((unsigned int)poison <= 0xFF) > > "if (poison >= 0)"? No cast needed. Hi Geert, We constraints valid inputs as [0, UCHAR_MAX], so the code follows the comment as below. /* * Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK) * into the buddy system. The freed pages will be poisoned with pattern * "poison" if it's within range [0, UCHAR_MAX]. * Return pages freed into the buddy system. */ Regards! Gerry > >> memset((void *)pos, poison, PAGE_SIZE); > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds > -- 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