Commit-ID: 1d953111b648e48923171c3c9cf17be2250544fa
Gitweb: http://git.kernel.org/tip/1d953111b648e48923171c3c9cf17be2250544fa
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Tue, 22 Aug 2017 17:59:28 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 25 Aug 2017 11:04:17 +0200
perf/core: Don't report zero PIDs for exiting tasks
The exiting/dead task has no PIDs and in this case perf_event_pid/tid()
return zero, change them to return -1 to distinguish this case from
idle threads.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho <acme@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170822155928.GA6892@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1ac5015..b411321 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1249,26 +1249,31 @@ unclone_ctx(struct perf_event_context *ctx)
return parent_ctx;
}
-static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
+static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
+ enum pid_type type)
{
+ u32 nr;
/*
* only top level events have the pid namespace they were created in
*/
if (event->parent)
event = event->parent;
- return task_tgid_nr_ns(p, event->ns);
+ nr = __task_pid_nr_ns(p, type, event->ns);
+ /* avoid -1 if it is idle thread or runs in another ns */
+ if (!nr && !pid_alive(p))
+ nr = -1;
+ return nr;
}
-static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
+static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
{
- /*
- * only top level events have the pid namespace they were created in
- */
- if (event->parent)
- event = event->parent;
+ return perf_event_pid_type(event, p, __PIDTYPE_TGID);
+}
- return task_pid_nr_ns(p, event->ns);
+static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
+{
+ return perf_event_pid_type(event, p, PIDTYPE_PID);
}
/*
--
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