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From: Neil Brown <neilb@suse.de>
To: Christoph Lameter <clameter@sgi.com>
Date: Fri, 20 Apr 2007 14:28:19 +1000
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Cc: linux-kernel@vger.kernel.org
Subject: SLUB: kmem_cache_destroy doesn't - version 2.
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Hi again,
 I recently noticed that my slub-enabled kernel won't let me stop
and restart the NFS server.   It stops fine but on restart
it returns -ENOMEM.

It turns out that this is because kmem_cache_create is failing
because the name already exists in sysfs.

fs/nfsd/nfs4state creates 4 kmem_caches.
Two of them get shared:

  /sys/slab/nfsd4_files -> ../slab/eventpoll_pwq
  /sys/slab/nfsd4_stateids -> ../slab/kmalloc-128

When kmem_cache_destroy is called, the alias count is reduced
properly, but the alias symlink does not get removed.  So when we
try to create those caches again, it fails.

Not sure how best to fix this one.... kmem_cache_destroy currently
doesn't know which alias is being destroyed.

NeilBrown