[PATCH v2 2/2] schedstat: Expose /proc/pid/schedstat if CONFIG_SCHED_INFO is set

From: Naveen N. Rao
Date: Thu Jun 25 2015 - 14:25:27 EST


In the unlikely scenario that the kernel is booted with nodelayacct, we
dump all zeroes so as to make it clear that scheduler statistics are not
available.

Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
---
fs/proc/base.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 286a422..a299131 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -304,14 +304,17 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
}
#endif

-#ifdef CONFIG_SCHEDSTATS
+#ifdef CONFIG_SCHED_INFO
/*
* Provides /proc/PID/schedstat
*/
static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
- seq_printf(m, "%llu %llu %lu\n",
+ if (unlikely(!sched_info_on()))
+ seq_printf(m, "0 0 0\n");
+ else
+ seq_printf(m, "%llu %lld %ld\n",
(unsigned long long)task->se.sum_exec_runtime,
(unsigned long long)task->sched_info.run_delay,
task->sched_info.pcount);
@@ -2600,7 +2603,7 @@ static const struct pid_entry tgid_base_stuff[] = {
#ifdef CONFIG_STACKTRACE
ONE("stack", S_IRUSR, proc_pid_stack),
#endif
-#ifdef CONFIG_SCHEDSTATS
+#ifdef CONFIG_SCHED_INFO
ONE("schedstat", S_IRUGO, proc_pid_schedstat),
#endif
#ifdef CONFIG_LATENCYTOP
@@ -2948,7 +2951,7 @@ static const struct pid_entry tid_base_stuff[] = {
#ifdef CONFIG_STACKTRACE
ONE("stack", S_IRUSR, proc_pid_stack),
#endif
-#ifdef CONFIG_SCHEDSTATS
+#ifdef CONFIG_SCHED_INFO
ONE("schedstat", S_IRUGO, proc_pid_schedstat),
#endif
#ifdef CONFIG_LATENCYTOP
--
2.4.0

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