34b133f8e9
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>
12 lines
350 B
C
12 lines
350 B
C
/*
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* Pull in the generic implementation for the mutex fastpath.
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*
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* TODO: implement optimized primitives instead, or leave the generic
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* implementation in place, or pick the atomic_xchg() based generic
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* implementation. (see asm-generic/mutex-xchg.h for details)
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*/
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#include <asm-generic/mutex-dec.h>
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#define arch_mutex_cpu_relax() barrier()
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