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| author | Dave Hansen <dave.hansen@linux.intel.com> | 2014-01-28 14:24:50 -0800 |
|---|---|---|
| committer | Pekka Enberg <penberg@kernel.org> | 2014-01-31 13:40:34 +0200 |
| commit | 433a91ff5fa19e3eb70b12f7056f234aebd09ac2 (patch) | |
| tree | 9d0af35284088374a2a203cde24c4a7360d7abec | |
| parent | 26e4f2057516f1c457e0e95346a00303f983ad53 (diff) | |
| download | linux-stable-433a91ff5fa19e3eb70b12f7056f234aebd09ac2.tar.gz linux-stable-433a91ff5fa19e3eb70b12f7056f234aebd09ac2.tar.bz2 linux-stable-433a91ff5fa19e3eb70b12f7056f234aebd09ac2.zip | |
mm: sl[uo]b: fix misleading comments
On x86, SLUB creates and handles <=8192-byte allocations internally.
It passes larger ones up to the allocator. Saying "up to order 2" is,
at best, ambiguous. Is that order-1? Or (order-2 bytes)? Make
it more clear.
SLOB commits a similar sin. It *handles* page-size requests, but the
comment says that it passes up "all page size and larger requests".
SLOB also swaps around the order of the very-similarly-named
KMALLOC_SHIFT_HIGH and KMALLOC_SHIFT_MAX #defines. Make it
consistent with the order of the other two allocators.
Cc: Matt Mackall <mpm@selenic.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
| -rw-r--r-- | include/linux/slab.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h index 1e2f4fe12773..f76e956b4011 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -205,8 +205,8 @@ struct kmem_cache { #ifdef CONFIG_SLUB /* - * SLUB allocates up to order 2 pages directly and otherwise - * passes the request to the page allocator. + * SLUB directly allocates requests fitting in to an order-1 page + * (PAGE_SIZE*2). Larger requests are passed to the page allocator. */ #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1) #define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT) @@ -217,12 +217,12 @@ struct kmem_cache { #ifdef CONFIG_SLOB /* - * SLOB passes all page size and larger requests to the page allocator. + * SLOB passes all requests larger than one page to the page allocator. * No kmalloc array is necessary since objects of different sizes can * be allocated from the same page. */ -#define KMALLOC_SHIFT_MAX 30 #define KMALLOC_SHIFT_HIGH PAGE_SHIFT +#define KMALLOC_SHIFT_MAX 30 #ifndef KMALLOC_SHIFT_LOW #define KMALLOC_SHIFT_LOW 3 #endif |