perf_counter: frequency based adaptive irq_period, 32-bit fix
fix:
kernel/built-in.o: In function `perf_counter_alloc':
perf_counter.c:(.text+0x7ddc7): undefined reference to `__udivdi3'
[ Impact: build fix on 32-bit systems ]
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <1242394667.6642.1887.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 0ad1db4..728a595 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2942,7 +2942,7 @@
hwc = &counter->hw;
if (hw_event->freq && hw_event->irq_freq)
- hwc->irq_period = TICK_NSEC / hw_event->irq_freq;
+ hwc->irq_period = div64_u64(TICK_NSEC, hw_event->irq_freq);
else
hwc->irq_period = hw_event->irq_period;