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Date: Tue, 12 Jul 2011 09:13:13 +0300 From: Pekka Enberg <penberg@...nel.org> To: Eric Dumazet <eric.dumazet@...il.com> CC: Hugh Dickins <hughd@...gle.com>, Christoph Lameter <cl@...ux.com>, Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org Subject: Re: [PATCH next/mmotm] slub: partly fix freeze in __slab_free On 7/11/11 10:39 PM, Eric Dumazet wrote: > Le lundi 11 juillet 2011 à 11:58 -0700, Hugh Dickins a écrit : >> 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@...gle.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); >> -- > I suspect you hit the bug on 32bit arch ? > > What about following patch instead ? > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 3d76a43..1351d28 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -62,7 +62,7 @@ struct page { > struct { /* SLUB cmpxchg_double area */ > void *freelist; > union { > - unsigned long counters; > + u64 counters; > struct { > unsigned inuse:16; > unsigned objects:15; > Christoph? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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