From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx199.postini.com [74.125.245.199]) by kanga.kvack.org (Postfix) with SMTP id 6EE5A6B0032 for ; Mon, 19 Aug 2013 17:08:18 -0400 (EDT) Date: Mon, 19 Aug 2013 14:08:16 -0700 From: Andrew Morton Subject: Re: [PATCH] mm: Track vma changes with VM_SOFTDIRTY bit Message-Id: <20130819140816.6c35952c0bc19c480a9664d6@linux-foundation.org> In-Reply-To: <20130819195836.GO23919@moon> References: <20130819195836.GO23919@moon> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Cyrill Gorcunov Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andy Lutomirski , Pavel Emelyanov , Matt Mackall , Xiao Guangrong , Marcelo Tosatti , KOSAKI Motohiro , Stephen Rothwell , Peter Zijlstra , "Aneesh Kumar K.V" On Mon, 19 Aug 2013 23:58:36 +0400 Cyrill Gorcunov wrote: > Pavel reported that in case if vma area get unmapped and > then mapped (or expanded) in-place, the soft dirty tracker > won't be able to recognize this situation since it works on > pte level and ptes are get zapped on unmap, loosing soft > dirty bit of course. > > So to resolve this situation we need to track actions > on vma level, there VM_SOFTDIRTY flag comes in. When > new vma area created (or old expanded) we set this bit, > and keep it here until application calls for clearing > soft dirty bit. > > Thus when user space application track memory changes > now it can detect if vma area is renewed. Can we please update Documentation/vm/soft-dirty.txt for this? -- 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