From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 26 Jan 2007 10:10:27 -0800 From: Andrew Morton Subject: Re: [RFC] Track mlock()ed pages Message-Id: <20070126101027.90bf3e63.akpm@osdl.org> In-Reply-To: References: <45B9A00C.4040701@yahoo.com.au> <20070126031300.59f75b06.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Nick Piggin , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Fri, 26 Jan 2007 07:44:42 -0800 (PST) Christoph Lameter wrote: > On Fri, 26 Jan 2007, Andrew Morton wrote: > > > > > > Track mlocked pages via a ZVC > > > > Why? > > Large amounts of mlocked pages may be a problem for > > 1. Reclaim behavior. > > 2. Defragmentation > We know that. What has that to do with this patch? > > > You could perhaps go for a walk across all the other vmas which presently > > map this page. If any of them have VM_LOCKED, don't increment the counter. > > Similar on removal: only decrement the counter when the final mlocked VMA > > is dropping the pte. > > For that we would need an additional refcount for vmlocked maps in the > page struct. No you don't. The refcount is already there. It is "the sum of the VM_LOCKED VMAs which map this page". It might be impractical or expensive to calculate it, but it's there. -- 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