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e20e877958
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Steven Rostedt e20e877958 mm: remove unlikely() from page_mapping() 
page_mapping() has a unlikely that the mapping has PAGE_MAPPING_ANON set.
But running the annotated branch profiler on a normal desktop system doing
vairous tasks (xchat, evolution, firefox, distcc), it is not really that
unlikely that the mapping here will have the PAGE_MAPPING_ANON flag set:

 correct incorrect  %        Function                  File              Line
 ------- ---------  -        --------                  ----              ----
35935762 1270265395  97 page_mapping                   mm.h                 659
1306198001   143659   0 page_mapping                   mm.h                 657
203131478   121586   0 page_mapping                   mm.h                 657
 5415491     1116   0 page_mapping                   mm.h                 657
74899487     1116   0 page_mapping                   mm.h                 657
203132845      224   0 page_mapping                   mm.h                 659
 5415464       27   0 page_mapping                   mm.h                 659
   13552        0   0 page_mapping                   mm.h                 657
   13552        0   0 page_mapping                   mm.h                 659
  242630        0   0 page_mapping                   mm.h                 657
  242630        0   0 page_mapping                   mm.h                 659
74899487        0   0 page_mapping                   mm.h                 659

The page_mapping() is a static inline, which is why it shows up multiple
times.

The unlikely in page_mapping() was correct a total of 1909540379 times and
incorrect 1270533123 times, with a 39% being incorrect.  With this much of
an error, it's best to simply remove the unlikely and have the compiler
and branch prediction figure this out.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:32:36 -08:00
..
acpi Merge branch 'master' into for-next 2010-12-22 18:57:02 +01:00
asm-generic Revert "gpiolib: annotate gpio-intialization with __must_check" 2011-01-13 17:26:46 -08:00
crypto crypto: padlock - Move padlock.h into include/crypto 2011-01-07 14:52:00 +11:00
drm Merge branch 'drm-radeon-ni' of ../drm-radeon-next into drm-core-next 2011-01-10 09:27:06 +10:00
keys keys: add new key-type encrypted 2010-11-29 08:55:29 +11:00
linux mm: remove unlikely() from page_mapping() 2011-01-13 17:32:36 -08:00
math-emu
media Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
mtd
net Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
pcmcia
rdma
rxrpc
scsi Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block 2011-01-13 10:45:01 -08:00
sound Merge branch 'topic/asoc' into for-linus 2011-01-13 08:37:24 +01:00
trace mm: vmscan: rename lumpy_mode to reclaim_mode 2011-01-13 17:32:34 -08:00
video Merge branch 'fbdev/udlfb' 2011-01-06 18:10:09 +09:00
xen Merge branch 'stable/xenbus' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2011-01-12 08:37:35 -08:00
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