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author | Gerald Schaefer <gerald.schaefer@de.ibm.com> | 2011-01-05 12:48:14 +0100 |
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committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2011-01-05 12:47:31 +0100 |
commit | 34b133f8e94e39ff3cf4d1c1f67f2e07cdc3d54e (patch) | |
tree | 462da9df24831e825deca5987e0fd283034cdfde /Kconfig | |
parent | [S390] cio: fix ccwgroup unregistration race condition (diff) | |
download | linux-34b133f8e94e39ff3cf4d1c1f67f2e07cdc3d54e.tar.xz linux-34b133f8e94e39ff3cf4d1c1f67f2e07cdc3d54e.zip |
[S390] mutex: Introduce arch_mutex_cpu_relax()
The spinning mutex implementation uses cpu_relax() in busy loops as a
compiler barrier. Depending on the architecture, cpu_relax() may do more
than needed in this specific mutex spin loops. On System z we also give
up the time slice of the virtual cpu in cpu_relax(), which prevents
effective spinning on the mutex.
This patch replaces cpu_relax() in the spinning mutex code with
arch_mutex_cpu_relax(), which can be defined by each architecture that
selects HAVE_ARCH_MUTEX_CPU_RELAX. The default is still cpu_relax(), so
this patch should not affect other architectures than System z for now.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1290437256.7455.4.camel@thinkpad>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Kconfig')
0 files changed, 0 insertions, 0 deletions