From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 053B06B005A for ; Mon, 17 Aug 2009 05:48:17 -0400 (EDT) Message-ID: <4A8927DD.6060209@redhat.com> Date: Mon, 17 Aug 2009 17:50:21 +0800 From: Amerigo Wang MIME-Version: 1.0 Subject: Re: [Patch 8/8] kexec: allow to shrink reserved memory References: <20090812081731.5757.25254.sendpatchset@localhost.localdomain> <20090812081906.5757.39417.sendpatchset@localhost.localdomain> <4A83893D.50707@redhat.com> <4A83CD84.8040609@redhat.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: "Eric W. Biederman" Cc: linux-kernel@vger.kernel.org, tony.luck@intel.com, linux-ia64@vger.kernel.org, linux-mm@kvack.org, Neil Horman , Andi Kleen , akpm@linux-foundation.org, bernhard.walle@gmx.de, Fenghua Yu , Ingo Molnar , Anton Vorontsov List-ID: Eric W. Biederman wrote: > Amerigo Wang writes: > > >> Not that simple, marking it as "__init" means it uses some "__init" data which >> will be dropped after initialization. >> > > If we start with the assumption that we will be reserving to much and > will free the memory once we know how much we really need I see a very > simple way to go about this. We ensure that the reservation of crash > kernel memory is done through a normal allocation so that we have > struct page entries for every page. On 32bit x86 that is an extra 1MB > for a 128MB allocation. > > Then when it comes time to release that memory we clear whatever magic > flags we have on the page (like PG_reserve) and call free_page. > Hmm, my MM knowledge is not good enough to judge if this works... I need to check more MM source code. Can any MM people help? Thanks. -- 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