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authorHeiko Carstens <heiko.carstens@de.ibm.com>2014-03-02 13:09:47 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-04-14 06:50:05 -0700
commitd232ed0c0eee44a5d3bbc4f21f136a303e77c34d (patch)
treefce8d9dd14e2b6df04f3d97753afd4582ba2433a /init
parentd99a848a2aefccfc7bdc13f09a622006adb69f4b (diff)
downloadlwn-d232ed0c0eee44a5d3bbc4f21f136a303e77c34d.tar.gz
lwn-d232ed0c0eee44a5d3bbc4f21f136a303e77c34d.zip
futex: Allow architectures to skip futex_atomic_cmpxchg_inatomic() test
commit 03b8c7b623c80af264c4c8d6111e5c6289933666 upstream. If an architecture has futex_atomic_cmpxchg_inatomic() implemented and there is no runtime check necessary, allow to skip the test within futex_init(). This allows to get rid of some code which would always give the same result, and also allows the compiler to optimize a couple of if statements away. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Finn Thain <fthain@telegraphics.com.au> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Link: http://lkml.kernel.org/r/20140302120947.GA3641@osiris Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig7
1 files changed, 7 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 009a797dd242..d56cb03c1b49 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1387,6 +1387,13 @@ config FUTEX
support for "fast userspace mutexes". The resulting kernel may not
run glibc-based applications correctly.
+config HAVE_FUTEX_CMPXCHG
+ bool
+ help
+ Architectures should select this if futex_atomic_cmpxchg_inatomic()
+ is implemented and always working. This removes a couple of runtime
+ checks.
+
config EPOLL
bool "Enable eventpoll support" if EXPERT
default y