The patch titled
sched: CPU hotplug events must not destroy scheduler domains created by the cpusets
has been added to the -mm tree. Its filename is
sched-cpu-hotplug-events-must-not-destroy-scheduler-domains-created-by-the-cpusets.patch
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------------------------------------------------------
Subject: sched: CPU hotplug events must not destroy scheduler domains created by the cpusets
From: Max Krasnyansky <maxk@xxxxxxxxxxxx>
Currently sched domains created by the cpusets are completely destroyed
during CPU hotplug event handling. For each CPU hotplug event scheduler
attaches all CPUs to the NULL domain and then puts them all into a single
domain thereby destroying domains created by the cpusets.
The solution is simple, when cpusets are enabled scheduler should not
create the default domain and instead let cpusets rebuild the domains
based on the current settings. Which is exactly what the patch does.
Signed-off-by: Max Krasnyansky <maxk@xxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Paul Jackson <pj@xxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cpuset.c | 6 ++++++
kernel/sched.c | 8 ++++++++
2 files changed, 14 insertions(+)
diff -puN kernel/cpuset.c~sched-cpu-hotplug-events-must-not-destroy-scheduler-domains-created-by-the-cpusets kernel/cpuset.c
--- a/kernel/cpuset.c~sched-cpu-hotplug-events-must-not-destroy-scheduler-domains-created-by-the-cpusets
+++ a/kernel/cpuset.c
@@ -1890,6 +1890,12 @@ static void common_cpu_mem_hotplug_unplu
top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
scan_for_empty_cpusets(&top_cpuset);
+ /*
+ * Scheduler destroys domains on hotplug events.
+ * Rebuild them based on the current settings.
+ */
+ rebuild_sched_domains();
+
cgroup_unlock();
}
diff -puN kernel/sched.c~sched-cpu-hotplug-events-must-not-destroy-scheduler-domains-created-by-the-cpusets kernel/sched.c
--- a/kernel/sched.c~sched-cpu-hotplug-events-must-not-destroy-scheduler-domains-created-by-the-cpusets
+++ a/kernel/sched.c
@@ -7537,8 +7537,16 @@ static int update_sched_domains(struct n
return NOTIFY_DONE;
}
+#ifndef CONFIG_CPUSETS
+ /*
+ * Create default domain partitioning if cpusets are disabled.
+ * Otherwise we let cpusets rebuild the domains based on the
+ * current setup.
+ */
+
/* The hotplug lock is already held by cpu_up/cpu_down */
arch_init_sched_domains(&cpu_online_map);
+#endif
return NOTIFY_OK;
}
_
Patches currently in -mm which might be from maxk@xxxxxxxxxxxx are
linux-next.patch
sched-fix-memory-leak-in-the-cpu-hotplug-handing-logic.patch
sched-cpu-hotplug-events-must-not-destroy-scheduler-domains-created-by-the-cpusets.patch
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