[PATCH] x86_64: Add cpu_relax() to busy loops in PM timer code
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/kernel/pmtimer.c b/arch/x86_64/kernel/pmtimer.c
index 5c51d10..ee5ee48 100644
--- a/arch/x86_64/kernel/pmtimer.c
+++ b/arch/x86_64/kernel/pmtimer.c
@@ -86,7 +86,7 @@
for (a = b = inl(pmtmr_ioport) & ACPI_PM_MASK;
a == b;
b = inl(pmtmr_ioport) & ACPI_PM_MASK)
- ;
+ cpu_relax();
return b;
}
@@ -97,6 +97,7 @@
a = pmtimer_wait_tick();
do {
b = inl(pmtmr_ioport);
+ cpu_relax();
} while (cyc2us(b - a) < us);
}