Commit f6c7d5fe authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf_counter: theres more to overflow than writing events 



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: default avatarPeter 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: default avatarIngo Molnar <mingo@elte.hu>
parent b6276f35

arch/powerpc/kernel/perf_counter.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

}



/*

arch/x86/kernel/cpu/perf_counter.c

+2 −1
Original line number Diff line number Diff line
@@ -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);

include/linux/perf_counter.h

+2 −2
Original line number Diff line number Diff line
@@ -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

kernel/perf_counter.c

+23 −6
Original line number Diff line number Diff line
@@ -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,

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