From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id C916A6B02A4 for ; Thu, 29 Jul 2010 19:28:28 -0400 (EDT) Message-ID: <4C520E97.4010703@cs.columbia.edu> Date: Thu, 29 Jul 2010 19:28:23 -0400 From: Oren Laadan MIME-Version: 1.0 Subject: [FS/MM TOPIC] Support for checkpoint/restart in fs/mm Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: lsf10-pc@lists.linuxfoundation.org Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Linux Containers List-ID: [Topic] Support for checkpoint/restart in fs/mm. [Abstract] Linux-CR implements transparent application checkpoint-restart aiming for inclusion in the mainline kernel. We'd like to briefly present our approach, and discuss pending issues. (for more info on linux-cr: http://www.linux-cr.org/) * Quick review of the approach: Checkpoint: we add .checkpoint method to 'struct file_operations", (which so far simply calls a generic checkpoint function). Restart: to restore the state of an open fd we reopen it based on the pathname saved during checkpoint, and then some adjustments. * Handling of unlinked files: Unlinked files are accessible by their open fd only, but at restart the fd cannot be restored (re-opened) since the original pathname is gone. We'd like to suggset a .relink filesystem method to attach a (new) pathname to an existing inode. * Handling of fsnotify/inotify: Both fsnotify/inotify track inode(s) directly without respective dentry(s). However, to restore an inotify fd, we need to have had recorded the pathname to that inode to re-add the watch at restart. We'd like to discuss possibilities for doing so. * Tracking of mm/pages modification per-process: We envision two optimizations - pre-copy (for fast live-migration) and incremental checkpoints. Both require tracking memory changes such as mm layout and modified pages. Tracking needs to be done on a per-process basis. We'd like to discuss possible approaches. Thanks, Oren. -- 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