Thread (45 messages) 45 messages, 3 authors, 2018-08-18

Re: [PATCH v11 9/9] cpuset: Allow reporting of sched domain generation info

From: Peter Zijlstra <peterz@infradead.org>
Date: 2018-07-19 13:54:47
Also in: cgroups, lkml

On Sun, Jun 24, 2018 at 03:30:40PM +0800, Waiman Long wrote:
quoted hunk ↗ jump to hunk
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 07a5575..62b7e61 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
I still hate this patch.. it prints information already available in
sched_debug and has that rediculous on-stack buffer.
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