On Thu, 7 Feb 2008, Vegard Nossum wrote:
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -28,6 +28,7 @@
> #define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU
> */
> #define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory
> over cpuset */
> #define SLAB_TRACE 0x00200000UL /* Trace allocations and frees
> */
> +#define SLAB_NOTRACK 0x00400000UL /* Don't track use of
> uninitialized memory */
Ok new exception for tracking.
> index 3f05667..3b3dfb8 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> +#ifdef CONFIG_KMEMCHECK
> + if (s->flags & SLAB_NOTRACK)
> + flags |= __GFP_NOTRACK;
> +
> + /* Actually allocate twice as much, since we need to track the
> + * status of each byte within the allocation. */
> + if (!(flags & __GFP_NOTRACK)) {
> + pages += pages;
> + order += 1;
> + }
Hmmmm... You seem to assume that __GFP_NOTRACK can be passed to slab
function calls like kmalloc. That is pretty unreliable. Could we add
__GFP_NOTRACK to the flags on which the slab allocators BUG?
> @@ -1551,9 +1586,7 @@ static __always_inline void *slab_alloc(struct
> kmem_cache *s,
> local_irq_save(flags);
> c = get_cpu_slab(s, smp_processor_id());
> if (unlikely(!c->freelist || !node_match(c, node)))
> -
> object = __slab_alloc(s, gfpflags, node, addr, c);
> -
> else {
> object = c->freelist;
> c->freelist = object[c->offset];
Drop this hunk.
> @@ -2344,6 +2393,8 @@ EXPORT_SYMBOL(kmem_cache_destroy);
> struct kmem_cache kmalloc_caches[PAGE_SHIFT] __cacheline_aligned;
> EXPORT_SYMBOL(kmalloc_caches);
>
> +struct kmem_cache cache_cache;
> +
Why do we need a cache_cache?
> #ifdef CONFIG_ZONE_DMA
> static struct kmem_cache *kmalloc_caches_dma[PAGE_SHIFT];
> #endif
> @@ -2391,6 +2442,9 @@ static struct kmem_cache *create_kmalloc_cache(struct
> kmem_cache *s,
> if (gfp_flags & SLUB_DMA)
> flags = SLAB_CACHE_DMA;
>
> + if (gfp_flags & __GFP_NOTRACK)
> + flags |= SLAB_NOTRACK;
> +
> down_write(&slub_lock);
> if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
> flags, NULL))
Drop this one. create_kmalloc_cache is done only during bootstrap and
kmalloc caches either all have SLAB_NOTRACK set or all do not have it
set.
> @@ -2445,14 +2499,18 @@ static noinline struct kmem_cache
> *dma_kmalloc_cache(int index, gfp_t flags)
> if (kmalloc_caches_dma[index])
> goto unlock_out;
>
> +#ifdef CONFIG_KMEMCHECK
> + flags |= __GFP_NOTRACK;
> +#endif
> +
Same here.
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