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mm/dmapool.c: micro-optimisation remove unnecessary branch

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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.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200320173317.26408-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mateusz Nosek 2020-04-06 20:08:49 -07:00 committed by Linus Torvalds
parent 1d90b64910
commit 1386f7a3bf
1 changed files with 1 additions and 3 deletions
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4
mm/dmapool.c
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@ -144,9 +144,7 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
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)