diff options
| author | Denys Vlasenko <dvlasenk@redhat.com> | 2016-03-17 14:18:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-17 15:09:34 -0700 |
| commit | ee91ef6173e81819f5ff610c2485802081635657 (patch) | |
| tree | 7260d83f05803a90d0d7ca57db6af6c6d884af08 /include/linux/buffer_head.h | |
| parent | 075db1502ffd4ff8c58020167484a6e123ae01a3 (diff) | |
bufferhead: force inlining of buffer head flag operations
With both gcc 4.7.2 and 4.9.2, 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,
set_buffer_foo(), clear_buffer_foo() and similar functions get deinlined
about 60 times. Examples of disassembly:
<set_buffer_mapped> (14 copies, 43 calls):
55 push %rbp
48 89 e5 mov %rsp,%rbp
f0 80 0f 20 lock orb $0x20,(%rdi)
5d pop %rbp
c3 retq
<buffer_mapped> (3 copies, 34 calls):
48 8b 07 mov (%rdi),%rax
55 push %rbp
48 89 e5 mov %rsp,%rbp
48 c1 e8 05 shr $0x5,%rax
83 e0 01 and $0x1,%eax
5d pop %rbp
c3 retq
<set_buffer_new> (5 copies, 13 calls):
55 push %rbp
48 89 e5 mov %rsp,%rbp
f0 80 0f 40 lock orb $0x40,(%rdi)
5d pop %rbp
c3 retq
This patch fixes this via s/inline/__always_inline/.
This decreases vmlinux by about 3 kbytes.
text data bss dec hex filename
88200439 19905208 36421632 144527279 89d4faf vmlinux2
88197239 19905240 36421632 144524111 89d434f vmlinux
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/buffer_head.h')
| -rw-r--r-- | include/linux/buffer_head.h | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 89d9aa9e79bf..c67f052cc5e5 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -82,15 +82,15 @@ struct buffer_head { * and buffer_foo() functions. */ #define BUFFER_FNS(bit, name) \ -static inline void set_buffer_##name(struct buffer_head *bh) \ +static __always_inline void set_buffer_##name(struct buffer_head *bh) \ { \ set_bit(BH_##bit, &(bh)->b_state); \ } \ -static inline void clear_buffer_##name(struct buffer_head *bh) \ +static __always_inline void clear_buffer_##name(struct buffer_head *bh) \ { \ clear_bit(BH_##bit, &(bh)->b_state); \ } \ -static inline int buffer_##name(const struct buffer_head *bh) \ +static __always_inline int buffer_##name(const struct buffer_head *bh) \ { \ return test_bit(BH_##bit, &(bh)->b_state); \ } @@ -99,11 +99,11 @@ static inline int buffer_##name(const struct buffer_head *bh) \ * test_set_buffer_foo() and test_clear_buffer_foo() */ #define TAS_BUFFER_FNS(bit, name) \ -static inline int test_set_buffer_##name(struct buffer_head *bh) \ +static __always_inline int test_set_buffer_##name(struct buffer_head *bh) \ { \ return test_and_set_bit(BH_##bit, &(bh)->b_state); \ } \ -static inline int test_clear_buffer_##name(struct buffer_head *bh) \ +static __always_inline int test_clear_buffer_##name(struct buffer_head *bh) \ { \ return test_and_clear_bit(BH_##bit, &(bh)->b_state); \ } \ |