Messages in this thread | | | Date | Fri, 3 Jun 2011 08:49:10 +0300 | Subject | Re: [PATCH] slub: always align cpu_slab to honor cmpxchg_double requirement | From | Pekka Enberg <> |
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On Thu, Jun 2, 2011 at 9:13 PM, Chris Metcalf <cmetcalf@tilera.com> wrote: > On 6/2/2011 1:16 PM, David Rientjes wrote: >> On Thu, 2 Jun 2011, Chris Metcalf wrote: >>> On an architecture without CMPXCHG_LOCAL but with DEBUG_VM enabled, >>> the VM_BUG_ON() in __pcpu_double_call_return_bool() will cause an early >>> panic during boot unless we always align cpu_slab properly. >>> >>> In principle we could remove the alignment-testing VM_BUG_ON() for >>> architectures that don't have CMPXCHG_LOCAL, but leaving it in means >>> that new code will tend not to break x86 even if it is introduced >>> on another platform, and it's low cost to require alignment. >>> >>> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> >> Acked-by: David Rientjes <rientjes@google.com> >> >>> --- >>> This needs to be pushed for 3.0 to allow arch/tile to boot. >>> I'm happy to push it but I assume it would be better coming >>> from an mm or percpu tree. Thanks! >>> >> Should also be marked for stable for 2.6.39.x, right? > > No, in 2.6.39 the irqsafe_cpu_cmpxchg_double() was guarded under "#ifdef > CONFIG_CMPXCHG_LOCAL". Now it's not. I suppose we could take the comment > change in percpu.h for 2.6.39, but it probably doesn't merit churning the > stable tree.
Yup. Looks good. Christoph? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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