The patch titled
Subject: mm/dmapool.c: micro-optimisation remove unnecessary branch
has been added to the -mm tree. Its filename is
mm-dmapoolc-micro-optimisation-remove-unnecessary-branch.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-dmapoolc-micro-optimisation-remove-unnecessary-branch.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-dmapoolc-micro-optimisation-remove-unnecessary-branch.patch
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------------------------------------------------------
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>
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)
_
Patches currently in -mm which might be from mateusznosek0@xxxxxxxxx are
mm-micro-optimisation-save-two-branches-on-hot-page-allocation-path.patch
mm-page_allocc-micro-optimisation-remove-unnecessary-branch.patch
mm-vmscanc-clean-code-by-removing-unnecessary-assignment.patch
mm-compactionc-clean-code-by-removing-unnecessary-assignment.patch
mm-hugetlbc-clean-code-by-removing-unnecessary-initialization.patch
mm-shmemc-clean-code-by-removing-unnecessary-assignment.patch
mm-mm_initc-clean-code-use-build_bug_on-when-comparing-compile-time-constant.patch
mm-dmapoolc-micro-optimisation-remove-unnecessary-branch.patch
