From ef5f379de302884b9b7ad9b62587a942a9f0bb55 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Tue, 20 Aug 2024 14:22:10 +0200 Subject: [PATCH] mm: always inline _compound_head() with CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP=y We already force-inline page_fixed_fake_head(), page_is_fake_head() and PageTail(), however the compiler might decide that _compound_head() is not worthy to be inlined, because of page_fixed_fake_head(). The result is that, for example, PageAnonExclusive() now might involve a function call when checking PageHuge(), which performs a page_folio()->_compound_head() call. This can lead to a slight regression of the stress-ng.clone benchmark. This is not super-urgent to fix, but always inlining _compound_head() seems like the obvious thing to do for this primitive, similar to the other ones. This change restores the slight regression and a compilation with CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP=y shows no relevant bloat [2]: add/remove: 15/14 grow/shrink: 79/87 up/down: 12836/-13917 (-1081) ... Total: Before=32786363, After=32785282, chg -0.00% [1] https://lkml.kernel.org/r/817150f2-abf7-430f-9973-540bd6cdd26f@intel.com [2] https://lore.kernel.org/all/116e117c-2821-401d-8e62-b85cdec37f4a@redhat.com/ Link: https://lkml.kernel.org/r/20240820122210.660140-1-david@redhat.com Fixes: c0bff412e67b ("mm: allow anon exclusive check over hugetlb tail pages") Signed-off-by: David Hildenbrand Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202407301049.5051dc19-oliver.sang@intel.com Tested-by: Yin Fengwei Cc: Peter Xu Signed-off-by: Andrew Morton --- include/linux/page-flags.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 17175a328e6b..2515ae85f191 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -232,7 +232,7 @@ static __always_inline int page_is_fake_head(const struct page *page) return page_fixed_fake_head(page) != page; } -static inline unsigned long _compound_head(const struct page *page) +static __always_inline unsigned long _compound_head(const struct page *page) { unsigned long head = READ_ONCE(page->compound_head);