* Christoph Lameter ([EMAIL PROTECTED]) wrote:
> @@ -1638,18 +1668,26 @@ static void __always_inline slab_free(st
>                       struct page *page, void *x, void *addr)
>  {
>       void **object = (void *)x;
> -     unsigned long flags;
> +     void **freelist;
>       struct kmem_cache_cpu *c;
>  
> -     local_irq_save(flags);
> -     c = get_cpu_slab(s, smp_processor_id());
> -     if (likely(page == c->page && c->node >= 0)) {
> -             object[c->offset] = c->freelist;
> -             c->freelist = object;
> -     } else
> -             __slab_free(s, page, x, addr, c->offset);
> +     c = get_cpu_slab(s, raw_smp_processor_id());
> +     if (unlikely(c->node >= 0))
> +             goto slow;
> +
> +redo:
> +     freelist = c->freelist;
> +     smp_rmb();
> +     if (unlikely(page != c->page))
> +             goto slow;
>  
> -     local_irq_restore(flags);
> +     object[c->offset] = freelist;
> +
> +     if (unlikely(cmpxchg_local(&c->freelist, freelist, object) != freelist))

If you don't plan to disable preemption here, cmpxchg_local should
probably not be used.

> +             goto redo;
> +     return;
> +slow:
> +     __slab_free(s, page, x, addr, c->offset);
>  }
>  
>  void kmem_cache_free(struct kmem_cache *s, void *x)
> Index: linux-2.6.23-rc1/include/linux/slub_def.h
> ===================================================================
> --- linux-2.6.23-rc1.orig/include/linux/slub_def.h    2007-07-27 
> 19:30:03.000000000 -0700
> +++ linux-2.6.23-rc1/include/linux/slub_def.h 2007-07-27 21:15:27.000000000 
> -0700
> @@ -12,11 +12,11 @@
>  #include <linux/kobject.h>
>  
>  struct kmem_cache_cpu {
> -     void **freelist;
> -     struct page *page;
> -     int node;
> -     unsigned int offset;
> -     unsigned int objsize;
> +     void **freelist;        /* Updated through atomic ops */
> +     struct page *page;      /* Updated with interrupts disabled */
> +     int node;               /* Updated with interrupts disabled */
> +     unsigned int offset;    /* Set up on kmem_cache_create() */
> +     unsigned int objsize;   /* Set up on kmem_cache_create() */
>  };
>  
>  struct kmem_cache_node {

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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