From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH] mm, fs: Obey gfp_mapping for add_to_page_cache Date: Thu, 1 Oct 2015 13:30:47 +0200 Message-ID: <20151001113046.GA24077@dhcp22.suse.cz> References: <1443193461-31402-1-git-send-email-mhocko@kernel.org> <20150929150246.286cc6013bce3eec170376aa@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Dave Chinner , Theodore Ts'o , Ming Lei , Andreas Dilger , Oleg Drokin , Al Viro , Christoph Hellwig , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, xfs-VZNHf3L845pBDgjK7y7TUQ@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Andrew Morton Return-path: Content-Disposition: inline In-Reply-To: <20150929150246.286cc6013bce3eec170376aa-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-cifs.vger.kernel.org On Tue 29-09-15 15:02:46, Andrew Morton wrote: > On Fri, 25 Sep 2015 17:04:21 +0200 mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org wrote: > > > From: Michal Hocko > > > > 6afdb859b710 ("mm: do not ignore mapping_gfp_mask in page cache > > allocation paths) has caught some users of hardcoded GFP_KERNEL > > used in the page cache allocation paths. This, however, wasn't complete > > and there were others which went unnoticed. > > > > Dave Chinner has reported the following deadlock for xfs on loop device: > > : With the recent merge of the loop device changes, I'm now seeing > > : XFS deadlock on my single CPU, 1GB RAM VM running xfs/073. > > : > > : The deadlocked is as follows: > > : > > : kloopd1: loop_queue_read_work > > : xfs_file_iter_read > > : lock XFS inode XFS_IOLOCK_SHARED (on image file) > > : page cache read (GFP_KERNEL) > > : radix tree alloc > > : memory reclaim > > : reclaim XFS inodes > > : log force to unpin inodes > > : > > : > > : xfs-cil/loop1: > > : xlog_cil_push > > : xlog_write > > : > > : xlog_state_get_iclog_space() > > : > > : > > : > > : kloopd1: loop_queue_write_work > > : xfs_file_write_iter > > : lock XFS inode XFS_IOLOCK_EXCL (on image file) > > : > > : > > : i.e. the kloopd, with it's split read and write work queues, has > > : introduced a dependency through memory reclaim. i.e. that writes > > : need to be able to progress for reads make progress. > > : > > : The problem, fundamentally, is that mpage_readpages() does a > > : GFP_KERNEL allocation, rather than paying attention to the inode's > > : mapping gfp mask, which is set to GFP_NOFS. > > : > > : The didn't used to happen, because the loop device used to issue > > : reads through the splice path and that does: > > : > > : error = add_to_page_cache_lru(page, mapping, index, > > : GFP_KERNEL & mapping_gfp_mask(mapping)); > > > > This has changed by aa4d86163e4 (block: loop: switch to VFS ITER_BVEC). > > xfs-on-loop deadlocks since April would appear to warrant a -stable > backport, yes? Yeah, stable 4.1+ > > this is a rebase on top of the current mmotm > > (2015-09-22-15-28) > > So I've redone the patch against current mainline. Thanks! -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html