From 94054fa3fca1fd78db02cb3d68d5627120f0a1d4 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Mon, 31 Oct 2011 17:07:45 -0700 Subject: [PATCH] xfs: warn if direct reclaim tries to writeback pages Direct reclaim should never writeback pages. For now, handle the situation and warn about it. Ultimately, this will be a BUG_ON. Signed-off-by: Mel Gorman Cc: Dave Chinner Cc: Christoph Hellwig Cc: Johannes Weiner Cc: Wu Fengguang Cc: Jan Kara Cc: Minchan Kim Cc: Rik van Riel Cc: Mel Gorman Cc: Alex Elder Cc: Theodore Ts'o Cc: Chris Mason Cc: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/xfs/xfs_aops.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 11b2aad982d4..33b13310ee0c 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -902,11 +902,11 @@ xfs_vm_writepage( * random callers for direct reclaim or memcg reclaim. We explicitly * allow reclaim from kswapd as the stack usage there is relatively low. * - * This should really be done by the core VM, but until that happens - * filesystems like XFS, btrfs and ext4 have to take care of this - * by themselves. + * This should never happen except in the case of a VM regression so + * warn about it. */ - if ((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC) + if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == + PF_MEMALLOC)) goto redirty; /* -- 2.20.1