From b223221956675ce8a7b436d198ced974bb388571 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 6 May 2011 02:54:04 +0000 Subject: [PATCH] xfs: ensure reclaim cursor is reset correctly at end of AG On a 32 bit highmem PowerPC machine, the XFS inode cache was growing without bound and exhausting low memory causing the OOM killer to be triggered. After some effort, the problem was reproduced on a 32 bit x86 highmem machine. The problem is that the per-ag inode reclaim index cursor was not getting reset to the start of the AG if the radix tree tag lookup found no more reclaimable inodes. Hence every further reclaim attempt started at the same index beyond where any reclaimable inodes lay, and no further background reclaim ever occurred from the AG. Without background inode reclaim the VM driven cache shrinker simply cannot keep up with cache growth, and OOM is the result. While the change that exposed the problem was the conversion of the inode reclaim to use work queues for background reclaim, it was not the cause of the bug. The bug was introduced when the cursor code was added, just waiting for some weird configuration to strike.... Signed-off-by: Dave Chinner Tested-By: Christian Kujau Reviewed-by: Christoph Hellwig Reviewed-by: Alex Elder --- fs/xfs/linux-2.6/xfs_sync.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c index e4f9c1b0836c..3e898a48122d 100644 --- a/fs/xfs/linux-2.6/xfs_sync.c +++ b/fs/xfs/linux-2.6/xfs_sync.c @@ -926,6 +926,7 @@ restart: XFS_LOOKUP_BATCH, XFS_ICI_RECLAIM_TAG); if (!nr_found) { + done = 1; rcu_read_unlock(); break; } -- 2.39.5