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> Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
