From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 0CDCC82970 for ; Wed, 10 Aug 2016 05:45:20 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id 1so54128471wmz.2 for ; Wed, 10 Aug 2016 02:45:19 -0700 (PDT) Received: from mail-wm0-x242.google.com (mail-wm0-x242.google.com. [2a00:1450:400c:c09::242]) by mx.google.com with ESMTPS id jv2si39049036wjc.268.2016.08.10.02.45.18 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 10 Aug 2016 02:45:18 -0700 (PDT) Received: by mail-wm0-x242.google.com with SMTP id o80so8437584wme.0 for ; Wed, 10 Aug 2016 02:45:18 -0700 (PDT) Date: Wed, 10 Aug 2016 18:44:42 +0900 From: Sergey Senozhatsky Subject: Re: [PATCH 2/5] mm/debug_pagealloc: don't allocate page_ext if we don't use guard page Message-ID: <20160810094442.GA674@swordfish> References: <1470809784-11516-1-git-send-email-iamjoonsoo.kim@lge.com> <1470809784-11516-3-git-send-email-iamjoonsoo.kim@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1470809784-11516-3-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: js1304@gmail.com Cc: Andrew Morton , Vlastimil Babka , Minchan Kim , Michal Hocko , Sergey Senozhatsky , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Joonsoo Kim On (08/10/16 15:16), js1304@gmail.com wrote: > From: Joonsoo Kim > > What debug_pagealloc does is just mapping/unmapping page table. > Basically, it doesn't need additional memory space to memorize something. > But, with guard page feature, it requires additional memory to distinguish > if the page is for guard or not. Guard page is only used when > debug_guardpage_minorder is non-zero so this patch removes additional > memory allocation (page_ext) if debug_guardpage_minorder is zero. > > It saves memory if we just use debug_pagealloc and not guard page. > > Signed-off-by: Joonsoo Kim Reviewed-by: Sergey Senozhatsky -ss -- 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