Commit 1386f7a3 authored Apr 06, 2020 by Mateusz Nosek Committed by Linus Torvalds Apr 07, 2020

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.

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>

parent 1d90b649

mm/dmapool.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -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);

		allocation = max_t(size_t, size, PAGE_SIZE);

		if (!boundary)

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