Subject: + mm-page_alloc-add-unlikely-macro-to-help-compiler-optimization.patch added to -mm tree To: iamjoonsoo.kim@xxxxxxx,hannes@xxxxxxxxxxx,mgorman@xxxxxxx,minchan@xxxxxxxxxx,riel@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Tue, 06 Aug 2013 15:13:39 -0700 The patch titled Subject: mm, page_alloc: add unlikely macro to help compiler optimization has been added to the -mm tree. Its filename is mm-page_alloc-add-unlikely-macro-to-help-compiler-optimization.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-add-unlikely-macro-to-help-compiler-optimization.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-add-unlikely-macro-to-help-compiler-optimization.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Subject: mm, page_alloc: add unlikely macro to help compiler optimization We rarely allocate a page with ALLOC_NO_WATERMARKS and it is used in slow path. For helping compiler optimization, add unlikely macro to ALLOC_NO_WATERMARKS checking. This patch doesn't have any effect now, because gcc already optimize this properly. But we cannot assume that gcc always does right and nobody re-evaluate if gcc do proper optimization with their change, for example, it is not optimized properly on v3.10. So adding compiler hint here is reasonable. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN mm/page_alloc.c~mm-page_alloc-add-unlikely-macro-to-help-compiler-optimization mm/page_alloc.c --- a/mm/page_alloc.c~mm-page_alloc-add-unlikely-macro-to-help-compiler-optimization +++ a/mm/page_alloc.c @@ -1898,7 +1898,7 @@ zonelist_scan: !cpuset_zone_allowed_softwall(zone, gfp_mask)) continue; BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK); - if (alloc_flags & ALLOC_NO_WATERMARKS) + if (unlikely(alloc_flags & ALLOC_NO_WATERMARKS)) goto try_this_zone; /* * Distribute pages in proportion to the individual _ Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are mm-hugetlb-move-up-the-code-which-check-availability-of-free-huge-page.patch mm-hugetlb-trivial-commenting-fix.patch mm-hugetlb-clean-up-alloc_huge_page.patch mm-hugetlb-fix-and-clean-up-node-iteration-code-to-alloc-or-free.patch mm-hugetlb-remove-redundant-list_empty-check-in-gather_surplus_pages.patch mm-hugetlb-do-not-use-a-page-in-page-cache-for-cow-optimization.patch mm-hugetlb-add-vm_noreserve-check-in-vma_has_reserves.patch mm-hugetlb-remove-decrement_hugepage_resv_vma.patch mm-hugetlb-decrement-reserve-count-if-vm_noreserve-alloc-page-cache.patch mm-hugetlb-decrement-reserve-count-if-vm_noreserve-alloc-page-cache-fix.patch mm-page_alloc-add-unlikely-macro-to-help-compiler-optimization.patch mm-move-pgtable-related-functions-to-right-place.patch swap-clean-up-ifdef-in-page_mapping.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html