From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e31.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id l9UKobN5001210 for ; Tue, 30 Oct 2007 16:50:37 -0400 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id l9UKoa6o112546 for ; Tue, 30 Oct 2007 14:50:36 -0600 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l9UKoapS021937 for ; Tue, 30 Oct 2007 14:50:36 -0600 Subject: Re: migratepage failures on reiserfs From: Badari Pulavarty In-Reply-To: <20071030135442.5d33c61c@think.oraclecorp.com> References: <1193768824.8904.11.camel@dyn9047017100.beaverton.ibm.com> <20071030135442.5d33c61c@think.oraclecorp.com> Content-Type: text/plain Date: Tue, 30 Oct 2007 13:54:05 -0800 Message-Id: <1193781245.8904.28.camel@dyn9047017100.beaverton.ibm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Chris Mason Cc: reiserfs-devel@vger.kernel.org, linux-mm , linux-fsdevel List-ID: On Tue, 2007-10-30 at 13:54 -0400, Chris Mason wrote: > On Tue, 30 Oct 2007 10:27:04 -0800 > Badari Pulavarty wrote: > > > Hi, > > > > While testing hotplug memory remove, I ran into this issue. Given a > > range of pages hotplug memory remove tries to migrate those pages. > > > > migrate_pages() keeps failing to migrate pages containing pagecache > > pages for reiserfs files. I noticed that reiserfs doesn't have > > ->migratepage() ops. So, fallback_migrate_page() code tries to > > do try_to_release_page(). try_to_release_page() fails to > > drop_buffers() since b_count == 1. Here is what my debug shows: > > > > migrate pages failed pfn 258111/flags 3f00000000801 > > bh c00000000b53f6e0 flags 110029 count 1 > > > > Any one know why the b_count == 1 and not getting dropped to zero ? > > If these are file data pages, the count is probably elevated as part of > the data=ordered tracking. You can verify this via b_private, or just > mount data=writeback to double check. Chris, That was my first assumption. But after looking at reiserfs_releasepage (), realized that it would do reiserfs_free_jh() and clears the b_private. I couldn't easily find out who has the ref. against this bh. bh c00000000bdaaf00 flags 110029 count 1 private 0 Thanks, Badari -- 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