From 4b0f326163f09e6d67f09dd5e1a70093cee710fc Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Thu, 17 Mar 2016 14:18:24 -0700 Subject: [PATCH] include/linux/page-flags.h: force inlining of selected page flag modifications Sometimes gcc mysteriously doesn't inline very small functions we expect to be inlined. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122 With this .config: http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os, the following functions get deinlined many times. Examples of disassembly: (43 copies, 141 calls): 55 push %rbp 48 89 e5 mov %rsp,%rbp f0 80 0f 08 lock orb $0x8,(%rdi) 5d pop %rbp c3 retq (10 copies, 134 calls): 48 8b 07 mov (%rdi),%rax 55 push %rbp 48 89 e5 mov %rsp,%rbp 48 c1 e8 0b shr $0xb,%rax 83 e0 01 and $0x1,%eax 5d pop %rbp c3 retq This patch fixes this via s/inline/__always_inline/. Code size decrease after the patch is ~7k: text data bss dec hex filename 92125002 20826048 36417536 149368586 8e72f0a vmlinux 92118087 20826112 36417536 149361735 8e71447 vmlinux7_pageops_after Signed-off-by: Denys Vlasenko Cc: Ingo Molnar Cc: Thomas Graf Cc: Peter Zijlstra Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/page-flags.h | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 597695523679..f4ed4f1b0c77 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -144,12 +144,12 @@ static inline struct page *compound_head(struct page *page) return page; } -static inline int PageTail(struct page *page) +static __always_inline int PageTail(struct page *page) { return READ_ONCE(page->compound_head) & 1; } -static inline int PageCompound(struct page *page) +static __always_inline int PageCompound(struct page *page) { return test_bit(PG_head, &page->flags) || PageTail(page); } @@ -184,31 +184,31 @@ static inline int PageCompound(struct page *page) * Macros to create function definitions for page flags */ #define TESTPAGEFLAG(uname, lname, policy) \ -static inline int Page##uname(struct page *page) \ +static __always_inline int Page##uname(struct page *page) \ { return test_bit(PG_##lname, &policy(page, 0)->flags); } #define SETPAGEFLAG(uname, lname, policy) \ -static inline void SetPage##uname(struct page *page) \ +static __always_inline void SetPage##uname(struct page *page) \ { set_bit(PG_##lname, &policy(page, 1)->flags); } #define CLEARPAGEFLAG(uname, lname, policy) \ -static inline void ClearPage##uname(struct page *page) \ +static __always_inline void ClearPage##uname(struct page *page) \ { clear_bit(PG_##lname, &policy(page, 1)->flags); } #define __SETPAGEFLAG(uname, lname, policy) \ -static inline void __SetPage##uname(struct page *page) \ +static __always_inline void __SetPage##uname(struct page *page) \ { __set_bit(PG_##lname, &policy(page, 1)->flags); } #define __CLEARPAGEFLAG(uname, lname, policy) \ -static inline void __ClearPage##uname(struct page *page) \ +static __always_inline void __ClearPage##uname(struct page *page) \ { __clear_bit(PG_##lname, &policy(page, 1)->flags); } #define TESTSETFLAG(uname, lname, policy) \ -static inline int TestSetPage##uname(struct page *page) \ +static __always_inline int TestSetPage##uname(struct page *page) \ { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } #define TESTCLEARFLAG(uname, lname, policy) \ -static inline int TestClearPage##uname(struct page *page) \ +static __always_inline int TestClearPage##uname(struct page *page) \ { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } #define PAGEFLAG(uname, lname, policy) \ @@ -371,7 +371,7 @@ PAGEFLAG(Idle, idle, PF_ANY) #define PAGE_MAPPING_KSM 2 #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM) -static inline int PageAnon(struct page *page) +static __always_inline int PageAnon(struct page *page) { page = compound_head(page); return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; @@ -384,7 +384,7 @@ static inline int PageAnon(struct page *page) * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any * anon_vma, but to that page's node of the stable tree. */ -static inline int PageKsm(struct page *page) +static __always_inline int PageKsm(struct page *page) { page = compound_head(page); return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == @@ -415,14 +415,14 @@ static inline int PageUptodate(struct page *page) return ret; } -static inline void __SetPageUptodate(struct page *page) +static __always_inline void __SetPageUptodate(struct page *page) { VM_BUG_ON_PAGE(PageTail(page), page); smp_wmb(); __set_bit(PG_uptodate, &page->flags); } -static inline void SetPageUptodate(struct page *page) +static __always_inline void SetPageUptodate(struct page *page) { VM_BUG_ON_PAGE(PageTail(page), page); /* @@ -456,12 +456,12 @@ static inline void set_page_writeback_keepwrite(struct page *page) __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY) -static inline void set_compound_head(struct page *page, struct page *head) +static __always_inline void set_compound_head(struct page *page, struct page *head) { WRITE_ONCE(page->compound_head, (unsigned long)head + 1); } -static inline void clear_compound_head(struct page *page) +static __always_inline void clear_compound_head(struct page *page) { WRITE_ONCE(page->compound_head, 0); } -- 2.20.1