x86: Conditionally update time when ack-ing pending irqs
On virtual environments, apic_read could take a long time. As a
result, under certain conditions the ack pending loop may exit
without any queued irqs left, but after more than one second. A
warning will be printed needlessly in this case.
If the loop is about to exit regardless of max_loops, don't
update it.
Signed-off-by: Shai Fultheim <shai@scalemp.com>
[ rebased and reworded the commit message]
Signed-off-by: Ido Yariv <ido@wizery.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1334873552-31346-1-git-send-email-ido@wizery.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index edc2448..3beab62 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1325,11 +1325,13 @@
acked);
break;
}
- if (cpu_has_tsc) {
- rdtscll(ntsc);
- max_loops = (cpu_khz << 10) - (ntsc - tsc);
- } else
- max_loops--;
+ if (queued) {
+ if (cpu_has_tsc) {
+ rdtscll(ntsc);
+ max_loops = (cpu_khz << 10) - (ntsc - tsc);
+ } else
+ max_loops--;
+ }
} while (queued && max_loops > 0);
WARN_ON(max_loops <= 0);
