From: Michal Hocko Subject: [PATCH 5/9 v2] xfs: use memalloc_nofs_{save,restore} instead of memalloc_noio* Date: Fri, 16 Dec 2016 23:00:28 +0100 Message-ID: <20161216220028.GB7645@dhcp22.suse.cz> References: <20161215140715.12732-1-mhocko@kernel.org> <20161215140715.12732-6-mhocko@kernel.org> <20161216163811.GG8447@bfoster.bfoster> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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 To: Brian Foster Return-path: Content-Disposition: inline In-Reply-To: <20161216163811.GG8447@bfoster.bfoster> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org On Fri 16-12-16 11:38:11, Brian Foster wrote: > On Thu, Dec 15, 2016 at 03:07:11PM +0100, Michal Hocko wrote: [...] > > @@ -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() ? Ups, you are right of course. Fixed. --- >From 47826112e59014030ffe27a673c1b1de345dd9de Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Thu, 15 Dec 2016 13:10:53 +0100 Subject: [PATCH] xfs: use memalloc_nofs_{save,restore} instead of memalloc_noio* 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. Changes since v1 - s@memalloc_noio_restore@memalloc_nofs_restore@ in _xfs_buf_map_pages as per Brian Foster 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/kmem.c b/fs/xfs/kmem.c index a76a05dae96b..d69ed5e76621 100644 --- a/fs/xfs/kmem.c +++ b/fs/xfs/kmem.c @@ -65,7 +65,7 @@ kmem_alloc(size_t size, xfs_km_flags_t flags) void * kmem_zalloc_large(size_t size, xfs_km_flags_t flags) { - unsigned noio_flag = 0; + unsigned nofs_flag = 0; void *ptr; gfp_t lflags; @@ -80,14 +80,14 @@ kmem_zalloc_large(size_t size, xfs_km_flags_t flags) * context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering * the filesystem here and potentially deadlocking. */ - if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) - noio_flag = memalloc_noio_save(); + if (flags & KM_NOFS) + nofs_flag = memalloc_nofs_save(); lflags = kmem_flags_convert(flags); ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL); - if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS)) - memalloc_noio_restore(noio_flag); + if (flags & KM_NOFS) + memalloc_nofs_restore(nofs_flag); return ptr; } diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index f31ae592dcae..e9eec256056c 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_nofs_restore(nofs_flag); if (!bp->b_addr) return -ENOMEM; -- 2.10.2 -- Michal Hocko SUSE Labs -- 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