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| author | Shai Fultheim <shai@scalemp.com> | 2012-04-20 01:12:32 +0300 |
|---|---|---|
| committer | Stefan Bader <stefan.bader@canonical.com> | 2015-05-29 11:54:14 +0200 |
| commit | 61be54706f6cc94a390e0578b700913c3b680ec8 (patch) | |
| tree | 9e311394ca6fb4b9346f68627350c841460c1f3a | |
| parent | faf8e0a76ac0b8d19c3c54d56af651fa01ac536b (diff) | |
| download | linux-2.6.32.y-drm33.z-61be54706f6cc94a390e0578b700913c3b680ec8.tar.gz | |
x86: Conditionally update time when ack-ing pending irqs
commit 42fa4250436304d4650fa271f37671f6cee24e08 upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from commit c9f1417be9acae3a9867f8bdab2b7924d76cf6ac)
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
| -rw-r--r-- | arch/x86/kernel/apic/apic.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 1d2d6704f5d12a..be4bf4c0865101 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1250,11 +1250,13 @@ void __cpuinit setup_local_APIC(void) 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); |