diff options
| author | akpm@osdl.org <akpm@osdl.org> | 2005-05-01 08:58:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-05-01 08:58:47 -0700 |
| commit | d59dd4620fb8d6422555a9e2b82a707718e68327 (patch) | |
| tree | 78205657d24efcaa3f8314064951ac3814ed95a7 /kernel/stop_machine.c | |
| parent | 0d8d4d42f2d00eb65262b49f4edd4cf7ef4eb6fc (diff) | |
| download | lwn-d59dd4620fb8d6422555a9e2b82a707718e68327.tar.gz lwn-d59dd4620fb8d6422555a9e2b82a707718e68327.zip | |
[PATCH] use smp_mb/wmb/rmb where possible
Replace a number of memory barriers with smp_ variants. This means we won't
take the unnecessary hit on UP machines.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/stop_machine.c')
| -rw-r--r-- | kernel/stop_machine.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index c39ed70af174..6116b25aa7cf 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -33,7 +33,7 @@ static int stopmachine(void *cpu) set_cpus_allowed(current, cpumask_of_cpu((int)(long)cpu)); /* Ack: we are alive */ - mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */ + smp_mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */ atomic_inc(&stopmachine_thread_ack); /* Simple state machine */ @@ -43,14 +43,14 @@ static int stopmachine(void *cpu) local_irq_disable(); irqs_disabled = 1; /* Ack: irqs disabled. */ - mb(); /* Must read state first. */ + smp_mb(); /* Must read state first. */ atomic_inc(&stopmachine_thread_ack); } else if (stopmachine_state == STOPMACHINE_PREPARE && !prepared) { /* Everyone is in place, hold CPU. */ preempt_disable(); prepared = 1; - mb(); /* Must read state first. */ + smp_mb(); /* Must read state first. */ atomic_inc(&stopmachine_thread_ack); } /* Yield in first stage: migration threads need to @@ -62,7 +62,7 @@ static int stopmachine(void *cpu) } /* Ack: we are exiting. */ - mb(); /* Must read state first. */ + smp_mb(); /* Must read state first. */ atomic_inc(&stopmachine_thread_ack); if (irqs_disabled) @@ -77,7 +77,7 @@ static int stopmachine(void *cpu) static void stopmachine_set_state(enum stopmachine_state state) { atomic_set(&stopmachine_thread_ack, 0); - wmb(); + smp_wmb(); stopmachine_state = state; while (atomic_read(&stopmachine_thread_ack) != stopmachine_num_threads) cpu_relax(); |