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| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-03-29 03:51:10 (GMT) |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-04-01 04:37:07 (GMT) |
| commit | 963e5d3b76d657f1ebcf3561446d2ba1872bbfa2 (patch) | |
| tree | 323acf4be02bddfebc9fe0a415b9e709fb8f5bf5 /arch | |
| parent | ecb78ab6f30106ab72a575a25b1cdfd1633b7ca2 (diff) | |
| download | linux-963e5d3b76d657f1ebcf3561446d2ba1872bbfa2.tar.xz | |
powerpc: Make decrementer interrupt robust against offlined CPUs
With some implementations, it is possible that a timer interrupt
occurs every few seconds on an offline CPU. In this case, just
re-arm the decrementer and return immediately
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index aa92696..375480c 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -577,14 +577,21 @@ void timer_interrupt(struct pt_regs * regs) struct clock_event_device *evt = &decrementer->event; u64 now; + /* Ensure a positive value is written to the decrementer, or else + * some CPUs will continue to take decrementer exceptions. + */ + set_dec(DECREMENTER_MAX); + + /* Some implementations of hotplug will get timer interrupts while + * offline, just ignore these + */ + if (!cpu_online(smp_processor_id())) + return; + trace_timer_interrupt_entry(regs); __get_cpu_var(irq_stat).timer_irqs++; - /* Ensure a positive value is written to the decrementer, or else - * some CPUs will continuue to take decrementer exceptions */ - set_dec(DECREMENTER_MAX); - #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC) if (atomic_read(&ppc_n_lost_interrupts) != 0) do_IRQ(regs); |