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authorIngo Molnar <mingo@elte.hu>2009-06-03 22:19:36 +0200
committerIngo Molnar <mingo@elte.hu>2009-06-03 23:39:51 +0200
commit128f048f0f0d2a477ad2555e7acd2ad15a1b6061 (patch)
tree5927a26da343af2189e47b497eec38680f19294f /kernel
parentperf_counter tools: Work around warnings in older GCCs (diff)
downloadlinux-128f048f0f0d2a477ad2555e7acd2ad15a1b6061.tar.xz
linux-128f048f0f0d2a477ad2555e7acd2ad15a1b6061.zip
perf_counter: Fix throttling lock-up
Throttling logic is broken and we can lock up with too small hw sampling intervals. Make the throttling code more robust: disable counters even if we already disabled them. ( Also clean up whitespace damage i noticed while reading various pieces of code related to throttling. ) Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/perf_counter.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index ab4455447f84..0bb03f15a5b6 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2822,11 +2822,20 @@ int perf_counter_overflow(struct perf_counter *counter,
if (!throttle) {
counter->hw.interrupts++;
- } else if (counter->hw.interrupts != MAX_INTERRUPTS) {
- counter->hw.interrupts++;
- if (HZ*counter->hw.interrupts > (u64)sysctl_perf_counter_limit) {
- counter->hw.interrupts = MAX_INTERRUPTS;
- perf_log_throttle(counter, 0);
+ } else {
+ if (counter->hw.interrupts != MAX_INTERRUPTS) {
+ counter->hw.interrupts++;
+ if (HZ*counter->hw.interrupts > (u64)sysctl_perf_counter_limit) {
+ counter->hw.interrupts = MAX_INTERRUPTS;
+ perf_log_throttle(counter, 0);
+ ret = 1;
+ }
+ } else {
+ /*
+ * Keep re-disabling counters even though on the previous
+ * pass we disabled it - just in case we raced with a
+ * sched-in and the counter got enabled again:
+ */
ret = 1;
}
}