From 91c6a05f72a996bee5133e76374ab3ad7d3b9b72 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Tue, 26 Jul 2016 15:22:08 -0700 Subject: [PATCH] mm: faster kmalloc_array(), kcalloc() When both arguments to kmalloc_array() or kcalloc() are known at compile time then their product is known at compile time but search for kmalloc cache happens at runtime not at compile time. Link: http://lkml.kernel.org/r/20160627213454.GA2440@p183.telecom.by Signed-off-by: Alexey Dobriyan Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/slab.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/slab.h b/include/linux/slab.h index aeb3e6d00a66..1a4ea551aae5 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -565,6 +565,8 @@ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags) { if (size != 0 && n > SIZE_MAX / size) return NULL; + if (__builtin_constant_p(n) && __builtin_constant_p(size)) + return kmalloc(n * size, flags); return __kmalloc(n * size, flags); } -- 2.11.0