On 10/05/2010 09:53 PM, Dave Chinner wrote: > On Mon, Oct 04, 2010 at 12:22:13PM +0200, Johannes Weiner wrote: >> Hi, >> >> On Mon, Oct 04, 2010 at 06:19:04PM +1100, Dave Chinner wrote: >>> On Fri, Oct 01, 2010 at 12:17:23PM -0500, Alex Elder wrote: >>>> On Fri, 2010-10-01 at 09:43 +0200, Johannes Weiner wrote: >>>>> When marking an inode reclaimable, a per-AG counter is increased, the >>>>> inode is tagged reclaimable in its per-AG tree, and, when this is the >>>>> first reclaimable inode in the AG, the AG entry in the per-mount tree >>>>> is also tagged. >>>>> >>>>> When an inode is finally reclaimed, however, it is only deleted from >>>>> the per-AG tree. Neither the counter is decreased, nor is the parent >>>>> tree's AG entry untagged properly. >>>>> >>>>> Since the tags in the per-mount tree are not cleared, the inode >>>>> shrinker iterates over all AGs that have had reclaimable inodes at one >>>>> point in time. >>>>> >>>>> The counters on the other hand signal an increasing amount of slab >>>>> objects to reclaim. Since "70e60ce xfs: convert inode shrinker to >>>>> per-filesystem context" this is not a real issue anymore because the >>>>> shrinker bails out after one iteration. >>>>> >>>>> But the problem was observable on a machine running v2.6.34, where the >>>>> reclaimable work increased and each process going into direct reclaim >>>>> eventually got stuck on the xfs inode shrinking path, trying to scan >>>>> several million objects. >>>>> >>>>> Fix this by properly unwinding the reclaimable-state tracking of an >>>>> inode when it is reclaimed. >>>>> >>>>> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> >>>>> Cc: stable@xxxxxxxxxx >>>> >>>> Yes, this looks right to me. The state was correctly >>>> adjusted in xfs_iget_cache_hit() when a RECLAIMABLE >>>> inode is found in the cache, but it was not done when >>>> reclaim completes. >>>> >>>> Reviewed-by: Alex Elder <aelder@xxxxxxx> >>> >>> Alex, can you push this to Linus ASAP? This needs to go back to >>> stable kernels as well.. >> >> Here is my suggestion of a backport to .34. Dave, Alex, do you >> approve? >> >> Hannes >> >> diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c >> index 6845db9..3314f2a 100644 >> --- a/fs/xfs/xfs_iget.c >> +++ b/fs/xfs/xfs_iget.c >> @@ -499,6 +499,7 @@ xfs_ireclaim( >> write_lock(&pag->pag_ici_lock); >> if (!radix_tree_delete(&pag->pag_ici_root, agino)) >> ASSERT(0); >> + pag->pag_ici_reclaimable--; >> write_unlock(&pag->pag_ici_lock); >> xfs_perag_put(pag); > > Looks good to me. > > Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx> i've got this in production and things seem to be acting a lot more like I would expect. Tested-by: John 'Warthog9' Hawley <warthog9@xxxxxxxxxx> _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
