diff options
| author | Gerald Schaefer <gerald.schaefer@de.ibm.com> | 2011-01-05 12:48:14 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2011-01-05 12:47:31 +0100 |
| commit | 34b133f8e94e39ff3cf4d1c1f67f2e07cdc3d54e (patch) | |
| tree | 462da9df24831e825deca5987e0fd283034cdfde /kernel/sched.c | |
| parent | c03017544e3b2e60aa3c8ae451fac01595f1bf11 (diff) | |
[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 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 297d1a0eedb..fe1c6243d25 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -75,6 +75,7 @@ #include <asm/tlb.h> #include <asm/irq_regs.h> +#include <asm/mutex.h> #include "sched_cpupri.h" #include "workqueue_sched.h" @@ -4214,7 +4215,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner) if (task_thread_info(rq->curr) != owner || need_resched()) return 0; - cpu_relax(); + arch_mutex_cpu_relax(); } return 1; |