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Subject[PATCH next/mmotm] slub: partly fix freeze in __slab_free
My load tests on PowerPC freeze within minutes in __slab_free().
I happened to try PPC first, didn't try without this fix on x86.

It looks as if the author was interrupted while devising the new
cmpxchg_double_slab() version of __slab_free(): its decision to
spin_lock_irqsave() depends on several uninitialized fields,
and fixing that (by copying page to new) mostly fixes it.

But I didn't think about it very much, and this may well not be what
the author intends; and I have seen a couple of much rarer freezes
in __slab_free() on PPC (not yet on x86) even after applying this.

Signed-off-by: Hugh Dickins <hughd@google.com>
---
mm/slub.c | 1 +
1 file changed, 1 insertion(+)
--- mmotm/mm/slub.c 2011-07-08 18:59:44.135443127 -0700
+++ linux/mm/slub.c 2011-07-10 05:07:08.000000000 -0700
@@ -2217,6 +2217,7 @@ static void __slab_free(struct kmem_cach
return;

do {
+ new = *page;
prior = page->freelist;
counters = page->counters;
set_freepointer(s, object, prior);

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