linux/arch/s390/include/asm/mutex.h

/*
 * Pull in the generic implementation for the mutex fastpath.
 *
 * TODO: implement optimized primitives instead, or leave the generic
 * implementation in place, or pick the atomic_xchg() based generic
 * implementation. (see asm-generic/mutex-xchg.h for details)
 */

#include <asm-generic/mutex-dec.h>

#define arch_mutex_cpu_relax()	barrier()
[PATCH] mutex subsystem, add default include/asm-*/mutex.h files add the per-arch mutex.h files for the remaining architectures. We default to asm-generic/mutex-dec.h, because that performs quite well on most arches. Arches that do not have atomic decrement/increment instructions should switch to mutex-xchg.h instead. Arches can also provide their own implementation for the mutex fastpath primitives. Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> 2006-01-09 23:59:19 +00:00			`/*`
			`* Pull in the generic implementation for the mutex fastpath.`
			`*`
			`* TODO: implement optimized primitives instead, or leave the generic`
			`* implementation in place, or pick the atomic_xchg() based generic`
			`* implementation. (see asm-generic/mutex-xchg.h for details)`
			`*/`

			`#include <asm-generic/mutex-dec.h>`
mutexes, sched: 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> 2010-11-22 14:47:36 +00:00
			`#define arch_mutex_cpu_relax() barrier()`