[patch 091/166] mm/dmapool.c: micro-optimisation remove unnecessary branch

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Mateusz Nosek <mateusznosek0@xxxxxxxxx>
Subject: mm/dmapool.c: micro-optimisation remove unnecessary branch

Previously there was a check if 'size' is aligned to 'align' and if not
then it was aligned.  This check was expensive as both branch and division
are expensive instructions in most architectures.  'ALIGN' function on
already aligned value will not change it, and as it is cheaper than branch
+ division it can be executed all the time and branch can be removed.

Link: http://lkml.kernel.org/r/20200320173317.26408-1-mateusznosek0@xxxxxxxxx
Signed-off-by: Mateusz Nosek <mateusznosek0@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/dmapool.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/mm/dmapool.c~mm-dmapoolc-micro-optimisation-remove-unnecessary-branch
+++ a/mm/dmapool.c
@@ -144,9 +144,7 @@ struct dma_pool *dma_pool_create(const c
 	else if (size < 4)
 		size = 4;
 
-	if ((size % align) != 0)
-		size = ALIGN(size, align);
-
+	size = ALIGN(size, align);
 	allocation = max_t(size_t, size, PAGE_SIZE);
 
 	if (!boundary)
_




[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux