From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f51.google.com (mail-pa0-f51.google.com [209.85.220.51]) by kanga.kvack.org (Postfix) with ESMTP id 340756B0031 for ; Thu, 3 Jul 2014 11:41:39 -0400 (EDT) Received: by mail-pa0-f51.google.com with SMTP id hz1so414208pad.38 for ; Thu, 03 Jul 2014 08:41:38 -0700 (PDT) Received: from blackbird.sr71.net (www.sr71.net. [198.145.64.142]) by mx.google.com with ESMTP id fi4si33193179pbb.193.2014.07.03.08.41.35 for ; Thu, 03 Jul 2014 08:41:37 -0700 (PDT) Message-ID: <53B579AD.1010201@sr71.net> Date: Thu, 03 Jul 2014 08:41:33 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [PATCH 00/10] RFC: userfault References: <1404319816-30229-1-git-send-email-aarcange@redhat.com> In-Reply-To: <1404319816-30229-1-git-send-email-aarcange@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli , qemu-devel@nongnu.org, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: "\"Dr. David Alan Gilbert\"" , Johannes Weiner , Andrew Morton , Android Kernel Team , Robert Love , Mel Gorman , Hugh Dickins , Rik van Riel , Dmitry Adamushko , Neil Brown , Mike Hommey , Taras Glek , Jan Kara , KOSAKI Motohiro , Michel Lespinasse , Minchan Kim , Keith Packard , "Huangpeng (Peter)" , Isaku Yamahata , Paolo Bonzini , Anthony Liguori , Stefan Hajnoczi , Wenchao Xia , Andrew Jones , Juan Quintela , Mel Gorman On 07/02/2014 09:50 AM, Andrea Arcangeli wrote: > The MADV_USERFAULT feature should be generic enough that it can > provide the userfaults to the Android volatile range feature too, on > access of reclaimed volatile pages. Maybe. I certainly can't keep track of all the versions of the variations of the volatile ranges patches. But, I don't think it's a given that this can be reused. First of all, volatile ranges is trying to replace ashmem and is going to require _some_ form of sharing. This mechanism, being tightly coupled to anonymous memory at the moment, is not a close fit for that. It's also important to call out that this is a VMA-based mechanism. I certainly can't predict what we'll merge for volatile ranges, but not all of them are VMA-based. We'd also need a mechanism on top of this to differentiate plain not-present pages from not-present-because-purged pages. That said, I _think_ this might fit well in to what the Mozilla guys wanted out of volatile ranges. I'm not confident about it, though. -- 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