[PATCH 07/10] perf: Add group parameter to perf_event_read()

[Sukadev Bhattiprolu]

Add a 'group' parameter to perf_event_read(). It will be used (set
to true) in a follow-on patch to update event times of the group.

Signed-off-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
---
 kernel/events/core.c |   17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 21a55d1..f38fe0b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3212,7 +3212,7 @@ static inline u64 perf_event_count(struct perf_event 
*event)
        return __perf_event_count(event);
 }
 
-static int perf_event_read(struct perf_event *event)
+static int perf_event_read(struct perf_event *event, bool group)
 {
        /*
         * If event is enabled and currently active on a CPU, update the
@@ -3235,7 +3235,12 @@ static int perf_event_read(struct perf_event *event)
                        update_context_time(ctx);
                        update_cgrp_time_from_event(event);
                }
-               update_event_times(event);
+
+               if (group)
+                       update_group_times(event);
+               else
+                       update_event_times(event);
+
                raw_spin_unlock_irqrestore(&ctx->lock, flags);
        }
 
@@ -3722,7 +3727,7 @@ static u64 perf_event_aggregate(struct perf_event *event, 
u64 *enabled,
        lockdep_assert_held(&event->child_mutex);
 
        list_for_each_entry(child, &event->child_list, child_list) {
-               (void)perf_event_read(child);
+               (void)perf_event_read(child, false);
                total += perf_event_count(child);
                *enabled += child->total_time_enabled;
                *running += child->total_time_running;
@@ -3776,7 +3781,7 @@ u64 perf_event_read_value(struct perf_event *event, u64 
*enabled, u64 *running)
 
        mutex_lock(&event->child_mutex);
 
-       (void)perf_event_read(event);
+       (void)perf_event_read(event, false);
        total = perf_event_aggregate(event, enabled, running);
 
        mutex_unlock(&event->child_mutex);
@@ -3831,7 +3836,7 @@ static int perf_read_group(struct perf_event *event,
 
                mutex_lock(&leader->child_mutex);
 
-               (void)perf_event_read(sub);
+               (void)perf_event_read(sub, false);
                values[n++] = perf_event_aggregate(sub, &enabled, &running);
 
                mutex_unlock(&leader->child_mutex);
@@ -3953,7 +3958,7 @@ static unsigned int perf_poll(struct file *file, 
poll_table *wait)
 
 static void _perf_event_reset(struct perf_event *event)
 {
-       (void)perf_event_read(event);
+       (void)perf_event_read(event, false);
        local64_set(&event->count, 0);
        perf_event_update_userpage(event);
 }
-- 
1.7.9.5

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