Messages in this thread | | | Subject | Re: [PATCH 3/7 v6] perf/core: Add a callback to perf events | From | Peter Zijlstra <> | Date | Tue, 17 Nov 2009 12:28:53 +0100 |
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On Sun, 2009-11-08 at 16:28 +0100, Frederic Weisbecker wrote: > A simple callback in a perf event can be used for multiple purposes. > For example it is useful for triggered based events like hardware > breakpoints that need a callback to dispatch a triggered breakpoint > event. > > v2: Simplify a bit the callback attribution as suggested by Paul > Mackerras
Yuck! So we add an opaque callback without semantics nor usage.
> --- > include/linux/perf_event.h | 7 ++++++- > kernel/perf_event.c | 14 ++++++++++---- > 2 files changed, 16 insertions(+), 5 deletions(-) > > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index fa151d4..8d54e6d 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -544,6 +544,8 @@ struct perf_pending_entry { > void (*func)(struct perf_pending_entry *); > }; > > +typedef void (*perf_callback_t)(struct perf_event *, void *); > + > /** > * struct perf_event - performance event kernel representation: > */ > @@ -639,6 +641,8 @@ struct perf_event { > struct event_filter *filter; > #endif > > + perf_callback_t callback; > + > #endif /* CONFIG_PERF_EVENTS */ > }; > > @@ -748,7 +752,8 @@ extern int perf_event_release_kernel(struct perf_event *event); > extern struct perf_event * > perf_event_create_kernel_counter(struct perf_event_attr *attr, > int cpu, > - pid_t pid); > + pid_t pid, > + perf_callback_t callback); > extern u64 perf_event_read_value(struct perf_event *event); > > struct perf_sample_data { > diff --git a/kernel/perf_event.c b/kernel/perf_event.c > index 02d4ff0..5087125 100644 > --- a/kernel/perf_event.c > +++ b/kernel/perf_event.c > @@ -4293,6 +4293,7 @@ perf_event_alloc(struct perf_event_attr *attr, > struct perf_event_context *ctx, > struct perf_event *group_leader, > struct perf_event *parent_event, > + perf_callback_t callback, > gfp_t gfpflags) > { > const struct pmu *pmu; > @@ -4335,6 +4336,11 @@ perf_event_alloc(struct perf_event_attr *attr, > > event->state = PERF_EVENT_STATE_INACTIVE; > > + if (!callback && parent_event) > + callback = parent_event->callback; > + > + event->callback = callback; > + > if (attr->disabled) > event->state = PERF_EVENT_STATE_OFF; > > @@ -4611,7 +4617,7 @@ SYSCALL_DEFINE5(perf_event_open, > } > > event = perf_event_alloc(&attr, cpu, ctx, group_leader, > - NULL, GFP_KERNEL); > + NULL, NULL, GFP_KERNEL); > err = PTR_ERR(event); > if (IS_ERR(event)) > goto err_put_context; > @@ -4668,7 +4674,7 @@ err_put_context: > */ > struct perf_event * > perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, > - pid_t pid) > + pid_t pid, perf_callback_t callback) > { > struct perf_event *event; > struct perf_event_context *ctx; > @@ -4683,7 +4689,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, > return NULL ; > > event = perf_event_alloc(attr, cpu, ctx, NULL, > - NULL, GFP_KERNEL); > + NULL, callback, GFP_KERNEL); > err = PTR_ERR(event); > if (IS_ERR(event)) > goto err_put_context; > @@ -4736,7 +4742,7 @@ inherit_event(struct perf_event *parent_event, > child_event = perf_event_alloc(&parent_event->attr, > parent_event->cpu, child_ctx, > group_leader, parent_event, > - GFP_KERNEL); > + NULL, GFP_KERNEL); > if (IS_ERR(child_event)) > return child_event; > get_ctx(child_ctx);
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