Messages in this thread | | | Date | Fri, 24 Jul 2020 12:55:43 +0200 | From | peterz@infradea ... | Subject | Re: [PATCH V7 07/14] perf/core: Add a new PERF_EV_CAP_COEXIST event capability |
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On Thu, Jul 23, 2020 at 10:11:10AM -0700, kan.liang@linux.intel.com wrote:
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index 3b22db08b6fb..93631e5389bf 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -576,9 +576,14 @@ typedef void (*perf_overflow_handler_t)(struct perf_event *, > * PERF_EV_CAP_SOFTWARE: Is a software event. > * PERF_EV_CAP_READ_ACTIVE_PKG: A CPU event (or cgroup event) that can be read > * from any CPU in the package where it is active. > + * PERF_EV_CAP_COEXIST: An event with this flag must coexist with other sibling > + * events, which have the same flag. If any event with the flag is detached > + * from the group, split the group into singleton events, and move the events > + * with the flag to the unrecoverable ERROR state. > */ > #define PERF_EV_CAP_SOFTWARE BIT(0) > #define PERF_EV_CAP_READ_ACTIVE_PKG BIT(1) > +#define PERF_EV_CAP_COEXIST BIT(2) > > #define SWEVENT_HLIST_BITS 8 > #define SWEVENT_HLIST_SIZE (1 << SWEVENT_HLIST_BITS) > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 7c436d705fbd..e35d549a356d 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -2133,10 +2133,28 @@ static inline struct list_head *get_event_list(struct perf_event *event) > return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active; > } > > +/* > + * If the event has PERF_EV_CAP_COEXIST capability, > + * schedule it out and move it into the ERROR state. > + */ > +static inline void perf_remove_coexist_events(struct perf_event *event) > +{ > + struct perf_event_context *ctx = event->ctx; > + struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); > + > + if (!(event->event_caps & PERF_EV_CAP_COEXIST)) > + return; > + > + event_sched_out(event, cpuctx, ctx); > + perf_event_set_state(event, PERF_EVENT_STATE_ERROR); > +}
Ah, so the problem here is that ERROR is actually recoverable using IOC_ENABLE. We don't want that either. Let me try and figure out of EXIT would work.
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