From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx109.postini.com [74.125.245.109]) by kanga.kvack.org (Postfix) with SMTP id 0E3806B02FF for ; Fri, 3 May 2013 18:58:27 -0400 (EDT) Received: from /spool/local by e8.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 3 May 2013 18:58:26 -0400 Received: from d01relay05.pok.ibm.com (d01relay05.pok.ibm.com [9.56.227.237]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id 4EA006E803A for ; Fri, 3 May 2013 18:58:16 -0400 (EDT) Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay05.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r43MwJAx330972 for ; Fri, 3 May 2013 18:58:19 -0400 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r43MwIJE010229 for ; Fri, 3 May 2013 19:58:18 -0300 Date: Thu, 2 May 2013 10:08:57 -0700 From: Matt Helsley Subject: Re: [PATCH 4/5] pagemap: Introduce the /proc/PID/pagemap2 file Message-ID: <20130502170857.GB24627@us.ibm.com> References: <51669E5F.4000801@parallels.com> <51669EA5.20209@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51669EA5.20209@parallels.com> Sender: owner-linux-mm@kvack.org List-ID: To: Pavel Emelyanov Cc: Andrew Morton , Linux MM , Linux Kernel Mailing List On Thu, Apr 11, 2013 at 03:29:41PM +0400, Pavel Emelyanov wrote: > This file is the same as the pagemap one, but shows entries with bits > 55-60 being zero (reserved for future use). Next patch will occupy one > of them. This approach doesn't scale as well as it could. As best I can see CRIU would do: for each vma in /proc//smaps for each page in /proc//pagemap2 if soft dirty bit copy page (possibly with pfn checks to avoid copying the same page mapped in multiple locations..) However, if soft dirty bit changes could be queued up (from say the fault handler and page table ops that map/unmap pages) and accumulated in something like an interval tree it could be something like: for each range of changed pages for each page in range copy page IOW something that scales with the number of changed pages rather than the number of mapped pages. So I wonder if CRIU would abandon pagemap2 in the future for something like this. Cheers, -Matt Helsley -- 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