lkml.org 
[lkml]   [2009]   [Jul]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:perfcounters/urgent] x86: atomic64: Reduce size of functions
Commit-ID:  3ac805d2afd3fa4a07cb5bcf352fd7fa83f28935
Gitweb: http://git.kernel.org/tip/3ac805d2afd3fa4a07cb5bcf352fd7fa83f28935
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Fri, 3 Jul 2009 12:51:19 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 3 Jul 2009 13:26:43 +0200

x86: atomic64: Reduce size of functions

cmpxchg8b is a huge instruction in terms of register footprint,
we almost never want to inline it, not even within the same
code module.

GCC 4.3 still messes up for two functions, under-judging the
true cost of this instruction - so annotate two key functions
to reduce the bloat:

arch/x86/lib/atomic64_32.o:

text data bss dec hex filename
1763 0 0 1763 6e3 atomic64_32.o.before
435 0 0 435 1b3 atomic64_32.o.after

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
arch/x86/lib/atomic64_32.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c
index 6195962..a910238 100644
--- a/arch/x86/lib/atomic64_32.c
+++ b/arch/x86/lib/atomic64_32.c
@@ -4,7 +4,7 @@
#include <asm/cmpxchg.h>
#include <asm/atomic.h>

-static inline u64 cmpxchg8b(u64 *ptr, u64 old, u64 new)
+static noinline u64 cmpxchg8b(u64 *ptr, u64 old, u64 new)
{
u32 low = new;
u32 high = new >> 32;
@@ -74,7 +74,7 @@ u64 atomic64_read(atomic64_t *ptr)
*
* Atomically adds @delta to @ptr and returns @delta + *@ptr
*/
-u64 atomic64_add_return(u64 delta, atomic64_t *ptr)
+noinline u64 atomic64_add_return(u64 delta, atomic64_t *ptr)
{
/*
* Try first with a (probably incorrect) assumption about

\
 
 \ /
  Last update: 2009-07-03 14:49    [from the cache]
©2003-2011 Jasper Spaans