[PATCH 2/8] xfs: Warn if direct reclaim tries to writeback pages

Mel Gorman
2011-07-21T16:29:08Z

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 <mgorman@suse.de>
---
fs/xfs/linux-2.6/xfs_aops.c | 9 +++++----
1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 79ce38b..c33a439 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -930,12 +930,13 @@ 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 ((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC) {
+ WARN_ON_ONCE(1);
goto redirty;
+ }

/*
* We need a transaction if there are delalloc or unwritten buffers
--
1.7.3.4