AuxXxilium/linux_dsm_epyc7002
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Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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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
This commit is contained in:
Linus Torvalds 2017-08-20 09:20:57 -07:00
commit e46db8d2ef
3 changed files with 48 additions and 19 deletions
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16
arch/x86/events/core.c
View File

@ -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)

4
include/linux/perf_event.h
View File

@ -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

47
kernel/events/core.c
View File

@ -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;
}