From: Dave Hansen Date: Tue, 28 Jan 2014 22:24:50 +0000 (-0800) Subject: mm: sl[uo]b: fix misleading comments X-Git-Tag: v3.14-rc1~5^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=433a91ff5fa19e3eb70b12f7056f234aebd09ac2;p=profile%2Fcommon%2Fkernel-common.git 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 Cc: Andrew Morton Acked-by: Christoph Lameter Acked-by: David Rientjes Signed-off-by: Dave Hansen Signed-off-by: Pekka Enberg --- diff --git a/include/linux/slab.h b/include/linux/slab.h index 1e2f4fe..f76e956 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