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authorakpm@osdl.org <akpm@osdl.org>2005-05-01 08:58:47 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-01 08:58:47 -0700
commitd59dd4620fb8d6422555a9e2b82a707718e68327 (patch)
tree78205657d24efcaa3f8314064951ac3814ed95a7 /kernel/stop_machine.c
parent0d8d4d42f2d00eb65262b49f4edd4cf7ef4eb6fc (diff)
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[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.c10
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();