Messages in this thread Patch in this message | | | From | Rob Herring <> | Subject | [PATCH v12 2/5] perf: Add a counter for number of user access events in context | Date | Wed, 27 Oct 2021 15:16:38 -0500 |
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For controlling user space counter access, we need to know if any event in a context (currently scheduled or not) is using user space counters. Walking the context's list of events would be slow, so add a counter to track this.
Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Rob Herring <robh@kernel.org> --- v10: - Re-added. - Maintain the count in the perf core v9: - Dropped v8: - new patch --- include/linux/perf_event.h | 1 + kernel/events/core.c | 4 ++++ 2 files changed, 5 insertions(+)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 34ebcc9af608..d733cac749e2 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -828,6 +828,7 @@ struct perf_event_context { int nr_events; int nr_active; + int nr_user; int is_active; int nr_stat; int nr_freq; diff --git a/kernel/events/core.c b/kernel/events/core.c index 744e8726c5b2..01290d150da3 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1808,6 +1808,8 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx) list_add_rcu(&event->event_entry, &ctx->event_list); ctx->nr_events++; + if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) + ctx->nr_user++; if (event->attr.inherit_stat) ctx->nr_stat++; @@ -1999,6 +2001,8 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx) event->attach_state &= ~PERF_ATTACH_CONTEXT; ctx->nr_events--; + if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) + ctx->nr_user--; if (event->attr.inherit_stat) ctx->nr_stat--; -- 2.32.0
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