[PATCH 3/8] ext4: Warn if direct reclaim tries to writeback pages

Mel Gorman
2011-07-21T16:30:24Z

Direct reclaim should never writeback pages. Warn if an attempt
is made.

Signed-off-by: Mel Gorman <mgorman@suse.de>
---
fs/ext4/inode.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e3126c0..95bb179 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2663,8 +2663,12 @@ static int ext4_writepage(struct page *page,
* We don't want to do block allocation, so redirty
* the page and return. We may reach here when we do
* a journal commit via journal_submit_inode_data_buffers.
- * We can also reach here via shrink_page_list
+ * We can also reach here via shrink_page_list but it
+ * should never be for direct reclaim so warn if that
+ * happens
*/
+ WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
+ PF_MEMALLOC);
goto redirty_page;
}
if (commit_write)
--
1.7.3.4