[PATCH v10 9/9] cpuset: Allow reporting of sched domain generation info

Waiman Long
2018-06-18T04:15:40Z

This patch enables us to report sched domain generation information.

If DYNAMIC_DEBUG is enabled, issuing the following command

echo "file cpuset.c +p" > /sys/kernel/debug/dynamic_debug/control

and setting loglevel to 8 will allow the kernel to show what scheduling
domain changes are being made.

Signed-off-by: Waiman Long <longman@redhat.com>
---
kernel/cgroup/cpuset.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index ed80663..2943d7c 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -836,6 +836,23 @@ static int generate_sched_domains(cpumask_var_t **domains,
return ndoms;
}

+#ifdef CONFIG_DEBUG_KERNEL
+static inline void debug_print_domains(cpumask_var_t *doms, int ndoms)
+{
+ int i;
+ char buf[200];
+ char *ptr, *end = buf + sizeof(buf) - 1;
+
+ for (i = 0, ptr = buf, *end = '\0'; i < ndoms; i++)
+ ptr += snprintf(ptr, end - ptr, "dom%d=%*pbl ", i,
+ cpumask_pr_args(doms[i]));
+
+ pr_debug("Generated %d domains: %s\n", ndoms, buf);
+}
+#else
+static inline void debug_print_domains(cpumask_var_t *doms, int ndoms) { }
+#endif
+
/*
* Rebuild scheduler domains.
*
@@ -871,6 +888,7 @@ static void rebuild_sched_domains_locked(void)

/* Generate domain masks and attrs */
ndoms = generate_sched_domains(&doms, &attr);
+ debug_print_domains(doms, ndoms);

/* Have scheduler rebuild the domains */
partition_sched_domains(ndoms, doms, attr);
--
1.8.3.1