[tip:core/types] linux/bitmap: Force inlining of bitmap weight functions

From: tip-bot for Denys Vlasenko
Date: Wed Aug 05 2015 - 16:14:27 EST


Commit-ID: 1a1d48a4a8fde49aedc045d894efe67173d59fe0
Gitweb: http://git.kernel.org/tip/1a1d48a4a8fde49aedc045d894efe67173d59fe0
Author: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
AuthorDate: Tue, 4 Aug 2015 16:15:14 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 5 Aug 2015 09:38:08 +0200

linux/bitmap: Force inlining of bitmap weight functions

With this config:

http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os

gcc-4.7.2 generates many copies of these tiny functions:

bitmap_weight (55 copies):
55 push %rbp
48 89 e5 mov %rsp,%rbp
e8 3f 3a 8b 00 callq __bitmap_weight
5d pop %rbp
c3 retq

hweight_long (23 copies):
55 push %rbp
e8 b5 65 8e 00 callq __sw_hweight64
48 89 e5 mov %rsp,%rbp
5d pop %rbp
c3 retq

See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122

This patch fixes this via s/inline/__always_inline/

While at it, replaced two "__inline__" with usual "inline"
(the rest of the source file uses the latter).

text data bss dec filename
86971357 17195880 36659200 140826437 vmlinux.before
86971120 17195912 36659200 140826232 vmlinux

Signed-off-by: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Thomas Graf <tgraf@xxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1438697716-28121-1-git-send-email-dvlasenk@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/bitmap.h | 2 +-
include/linux/bitops.h | 6 +++---
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index ea17cca..9653fdb 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -295,7 +295,7 @@ static inline int bitmap_full(const unsigned long *src, unsigned int nbits)
return find_first_zero_bit(src, nbits) == nbits;
}

-static inline int bitmap_weight(const unsigned long *src, unsigned int nbits)
+static __always_inline int bitmap_weight(const unsigned long *src, unsigned int nbits)
{
if (small_const_nbits(nbits))
return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 297f5bd..e635533 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -57,7 +57,7 @@ extern unsigned long __sw_hweight64(__u64 w);
(bit) < (size); \
(bit) = find_next_zero_bit((addr), (size), (bit) + 1))

-static __inline__ int get_bitmask_order(unsigned int count)
+static inline int get_bitmask_order(unsigned int count)
{
int order;

@@ -65,7 +65,7 @@ static __inline__ int get_bitmask_order(unsigned int count)
return order; /* We could be slightly more clever with -1 here... */
}

-static __inline__ int get_count_order(unsigned int count)
+static inline int get_count_order(unsigned int count)
{
int order;

@@ -75,7 +75,7 @@ static __inline__ int get_count_order(unsigned int count)
return order;
}

-static inline unsigned long hweight_long(unsigned long w)
+static __always_inline unsigned long hweight_long(unsigned long w)
{
return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
}
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