Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935367AbcLPQih (ORCPT ); Fri, 16 Dec 2016 11:38:37 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41176 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161101AbcLPQiO (ORCPT ); Fri, 16 Dec 2016 11:38:14 -0500 Date: Fri, 16 Dec 2016 11:38:11 -0500 From: Brian Foster To: Michal Hocko Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Dave Chinner , "Theodore Ts'o" , Chris Mason , David Sterba , Jan Kara , ceph-devel@vger.kernel.org, cluster-devel@redhat.com, linux-nfs@vger.kernel.org, logfs@logfs.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mtd@lists.infradead.org, reiserfs-devel@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net, linux-f2fs-devel@lists.sourceforge.net, linux-afs@lists.infradead.org, LKML , Michal Hocko Subject: Re: [PATCH 5/9] xfs: use memalloc_nofs_{save,restore} instead of memalloc_noio* Message-ID: <20161216163811.GG8447@bfoster.bfoster> References: <20161215140715.12732-1-mhocko@kernel.org> <20161215140715.12732-6-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161215140715.12732-6-mhocko@kernel.org> User-Agent: Mutt/1.7.1 (2016-10-04) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Fri, 16 Dec 2016 16:38:14 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2212 Lines: 64 On Thu, Dec 15, 2016 at 03:07:11PM +0100, Michal Hocko wrote: > From: Michal Hocko > > kmem_zalloc_large and _xfs_buf_map_pages use memalloc_noio_{save,restore} > API to prevent from reclaim recursion into the fs because vmalloc can > invoke unconditional GFP_KERNEL allocations and these functions might be > called from the NOFS contexts. The memalloc_noio_save will enforce > GFP_NOIO context which is even weaker than GFP_NOFS and that seems to be > unnecessary. Let's use memalloc_nofs_{save,restore} instead as it should > provide exactly what we need here - implicit GFP_NOFS context. > > Signed-off-by: Michal Hocko > --- > fs/xfs/kmem.c | 10 +++++----- > fs/xfs/xfs_buf.c | 8 ++++---- > 2 files changed, 9 insertions(+), 9 deletions(-) > ... > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > index f31ae592dcae..5c6f9bd4d8be 100644 > --- a/fs/xfs/xfs_buf.c > +++ b/fs/xfs/xfs_buf.c > @@ -441,17 +441,17 @@ _xfs_buf_map_pages( > bp->b_addr = NULL; > } else { > int retried = 0; > - unsigned noio_flag; > + unsigned nofs_flag; > > /* > * vm_map_ram() will allocate auxillary structures (e.g. > * pagetables) with GFP_KERNEL, yet we are likely to be under > * GFP_NOFS context here. Hence we need to tell memory reclaim > - * that we are in such a context via PF_MEMALLOC_NOIO to prevent > + * that we are in such a context via PF_MEMALLOC_NOFS to prevent > * memory reclaim re-entering the filesystem here and > * potentially deadlocking. > */ > - noio_flag = memalloc_noio_save(); > + nofs_flag = memalloc_nofs_save(); > do { > bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count, > -1, PAGE_KERNEL); > @@ -459,7 +459,7 @@ _xfs_buf_map_pages( > break; > vm_unmap_aliases(); > } while (retried++ <= 1); > - memalloc_noio_restore(noio_flag); > + memalloc_noio_restore(nofs_flag); memalloc_nofs_restore() ? Brian > > if (!bp->b_addr) > return -ENOMEM; > -- > 2.10.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html