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perf_counter: theres more to overflow than writing events

Browse source 
Prepare for more generic overflow handling. The new perf_counter_overflow()
method will handle the generic bits of the counter overflow, and can return
a !0 return value, in which case the counter should be (soft) disabled, so
that it won't count until it's properly disabled.

XXX: do powerpc and swcounter

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090406094517.812109629@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-04-06 11:45:04 +02:00 committed by Ingo Molnar
parent b6276f353b
commit f6c7d5fe58
4 changed files with 28 additions and 10 deletions
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2
arch/powerpc/kernel/perf_counter.c
View file

@ -732,7 +732,7 @@ static void record_and_restart(struct perf_counter *counter, long val,
* Finally record data if requested.
*/
if (record)
perf_counter_output(counter, 1, regs);
perf_counter_overflow(counter, 1, regs);
}
/*

3
arch/x86/kernel/cpu/perf_counter.c
View file

@ -800,7 +800,8 @@ again:
continue;
perf_save_and_restart(counter);
perf_counter_output(counter, nmi, regs);
if (perf_counter_overflow(counter, nmi, regs))
__pmc_generic_disable(counter, &counter->hw, bit);
}
hw_perf_ack_status(ack);

2
include/linux/perf_counter.h
View file

@ -491,7 +491,7 @@ extern int hw_perf_group_sched_in(struct perf_counter *group_leader,
struct perf_counter_context *ctx, int cpu);
extern void perf_counter_update_userpage(struct perf_counter *counter);
extern void perf_counter_output(struct perf_counter *counter,
extern int perf_counter_overflow(struct perf_counter *counter,
int nmi, struct pt_regs *regs);
/*
* Return 1 for a software counter, 0 for a hardware counter

27
kernel/perf_counter.c
View file

@ -1800,7 +1800,7 @@ static void perf_output_end(struct perf_output_handle *handle)
rcu_read_unlock();
}
void perf_counter_output(struct perf_counter *counter,
static void perf_counter_output(struct perf_counter *counter,
int nmi, struct pt_regs *regs)
{
int ret;
@ -2033,6 +2033,17 @@ void perf_counter_munmap(unsigned long addr, unsigned long len,
perf_counter_mmap_event(&mmap_event);
}
/*
* Generic counter overflow handling.
*/
int perf_counter_overflow(struct perf_counter *counter,
int nmi, struct pt_regs *regs)
{
perf_counter_output(counter, nmi, regs);
return 0;
}
/*
* Generic software counter infrastructure
*/
@ -2077,6 +2088,7 @@ static void perf_swcounter_set_period(struct perf_counter *counter)
static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
{
enum hrtimer_restart ret = HRTIMER_RESTART;
struct perf_counter *counter;
struct pt_regs *regs;
@ -2092,12 +2104,14 @@ static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
!counter->hw_event.exclude_user)
regs = task_pt_regs(current);
if (regs)
perf_counter_output(counter, 0, regs);
if (regs) {
if (perf_counter_overflow(counter, 0, regs))
ret = HRTIMER_NORESTART;
}
hrtimer_forward_now(hrtimer, ns_to_ktime(counter->hw.irq_period));
return HRTIMER_RESTART;
return ret;
}
static void perf_swcounter_overflow(struct perf_counter *counter,
@ -2105,7 +2119,10 @@ static void perf_swcounter_overflow(struct perf_counter *counter,
{
perf_swcounter_update(counter);
perf_swcounter_set_period(counter);
perf_counter_output(counter, nmi, regs);
if (perf_counter_overflow(counter, nmi, regs))
/* soft-disable the counter */
;
}
static int perf_swcounter_match(struct perf_counter *counter,