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Commit e46db8d2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull perf fixes from Thomas Gleixner:
 "Two fixes for the perf subsystem:

   - Fix an inconsistency of RDPMC mm struct tagging across exec() which
     causes RDPMC to fault.

   - Correct the timestamp mechanics across IOC_DISABLE/ENABLE which
     causes incorrect timestamps and total time calculations"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix time on IOC_ENABLE
  perf/x86: Fix RDPMC vs. mm_struct tracking
parents 9dae41a2 9b231d9f

arch/x86/events/core.c

+7 −9
Original line number Diff line number Diff line
@@ -2114,7 +2114,7 @@ static void refresh_pce(void *ignored) 
	load_mm_cr4(this_cpu_read(cpu_tlbstate.loaded_mm));

}



static void x86_pmu_event_mapped(struct perf_event *event)

static void x86_pmu_event_mapped(struct perf_event *event, struct mm_struct *mm)

{

	if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))

		return;
@@ -2129,22 +2129,20 @@ static void x86_pmu_event_mapped(struct perf_event *event) 
	 * For now, this can't happen because all callers hold mmap_sem

	 * for write.  If this changes, we'll need a different solution.

	 */

	lockdep_assert_held_exclusive(&current->mm->mmap_sem);

	lockdep_assert_held_exclusive(&mm->mmap_sem);



	if (atomic_inc_return(&current->mm->context.perf_rdpmc_allowed) == 1)

		on_each_cpu_mask(mm_cpumask(current->mm), refresh_pce, NULL, 1);

	if (atomic_inc_return(&mm->context.perf_rdpmc_allowed) == 1)

		on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1);

}



static void x86_pmu_event_unmapped(struct perf_event *event)

static void x86_pmu_event_unmapped(struct perf_event *event, struct mm_struct *mm)

{

	if (!current->mm)

		return;



	if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))

		return;



	if (atomic_dec_and_test(&current->mm->context.perf_rdpmc_allowed))

		on_each_cpu_mask(mm_cpumask(current->mm), refresh_pce, NULL, 1);

	if (atomic_dec_and_test(&mm->context.perf_rdpmc_allowed))

		on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1);

}



static int x86_pmu_event_idx(struct perf_event *event)

include/linux/perf_event.h

+2 −2
Original line number Diff line number Diff line
@@ -310,8 +310,8 @@ struct pmu { 
	 * Notification that the event was mapped or unmapped.  Called

	 * in the context of the mapping task.

	 */

	void (*event_mapped)		(struct perf_event *event); /*optional*/

	void (*event_unmapped)		(struct perf_event *event); /*optional*/

	void (*event_mapped)		(struct perf_event *event, struct mm_struct *mm); /* optional */

	void (*event_unmapped)		(struct perf_event *event, struct mm_struct *mm); /* optional */



	/*

	 * Flags for ->add()/->del()/ ->start()/->stop(). There are

kernel/events/core.c

+39 −8
Original line number Diff line number Diff line
@@ -2217,6 +2217,33 @@ static int group_can_go_on(struct perf_event *event, 
	return can_add_hw;

}



/*

 * Complement to update_event_times(). This computes the tstamp_* values to

 * continue 'enabled' state from @now, and effectively discards the time

 * between the prior tstamp_stopped and now (as we were in the OFF state, or

 * just switched (context) time base).

 *

 * This further assumes '@event->state == INACTIVE' (we just came from OFF) and

 * cannot have been scheduled in yet. And going into INACTIVE state means

 * '@event->tstamp_stopped = @now'.

 *

 * Thus given the rules of update_event_times():

 *

 *   total_time_enabled = tstamp_stopped - tstamp_enabled

 *   total_time_running = tstamp_stopped - tstamp_running

 *

 * We can insert 'tstamp_stopped == now' and reverse them to compute new

 * tstamp_* values.

 */

static void __perf_event_enable_time(struct perf_event *event, u64 now)

{

	WARN_ON_ONCE(event->state != PERF_EVENT_STATE_INACTIVE);



	event->tstamp_stopped = now;

	event->tstamp_enabled = now - event->total_time_enabled;

	event->tstamp_running = now - event->total_time_running;

}



static void add_event_to_ctx(struct perf_event *event,

			       struct perf_event_context *ctx)

{
@@ -2224,9 +2251,12 @@ static void add_event_to_ctx(struct perf_event *event, 


	list_add_event(event, ctx);

	perf_group_attach(event);

	event->tstamp_enabled = tstamp;

	event->tstamp_running = tstamp;

	event->tstamp_stopped = tstamp;

	/*

	 * We can be called with event->state == STATE_OFF when we create with

	 * .disabled = 1. In that case the IOC_ENABLE will call this function.

	 */

	if (event->state == PERF_EVENT_STATE_INACTIVE)

		__perf_event_enable_time(event, tstamp);

}



static void ctx_sched_out(struct perf_event_context *ctx,
@@ -2471,10 +2501,11 @@ static void __perf_event_mark_enabled(struct perf_event *event) 
	u64 tstamp = perf_event_time(event);



	event->state = PERF_EVENT_STATE_INACTIVE;

	event->tstamp_enabled = tstamp - event->total_time_enabled;

	__perf_event_enable_time(event, tstamp);

	list_for_each_entry(sub, &event->sibling_list, group_entry) {

		/* XXX should not be > INACTIVE if event isn't */

		if (sub->state >= PERF_EVENT_STATE_INACTIVE)

			sub->tstamp_enabled = tstamp - sub->total_time_enabled;

			__perf_event_enable_time(sub, tstamp);

	}

}
@@ -5090,7 +5121,7 @@ static void perf_mmap_open(struct vm_area_struct *vma) 
		atomic_inc(&event->rb->aux_mmap_count);



	if (event->pmu->event_mapped)

		event->pmu->event_mapped(event);

		event->pmu->event_mapped(event, vma->vm_mm);

}



static void perf_pmu_output_stop(struct perf_event *event);
@@ -5113,7 +5144,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) 
	unsigned long size = perf_data_size(rb);



	if (event->pmu->event_unmapped)

		event->pmu->event_unmapped(event);

		event->pmu->event_unmapped(event, vma->vm_mm);



	/*

	 * rb->aux_mmap_count will always drop before rb->mmap_count and
@@ -5411,7 +5442,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) 
	vma->vm_ops = &perf_mmap_vmops;



	if (event->pmu->event_mapped)

		event->pmu->event_mapped(event);

		event->pmu->event_mapped(event, vma->vm_mm);



	return ret;

}