[PATCH v4 03/11] cgroup/cpuset: Drive kernel-noise housekeeping updates from isolated partitions

[Jing Wu <realwujing@gmail.com>]

An isolated cpuset partition already updates the HK_TYPE_DOMAIN
housekeeping mask.  Extend it to also update the kernel-noise masks
(HK_TYPE_KERNEL_NOISE and HK_TYPE_MANAGED_IRQ) so that creating or
destroying an isolated partition reconfigures the full set of
housekeeping cpumasks.

The sched domain mask is updated first because the workqueue flush and
timer migration paths depend on it; the kernel-noise masks are updated
afterwards via housekeeping_update_types().

housekeeping_update() and housekeeping_update_types() are called after
dropping cpus_read_lock and cpuset_mutex, with only cpuset_top_mutex held
for mutual exclusion.

Co-developed-by: Qiliang Yuan <yuanql9@chinatelecom.cn>
Signed-off-by: Qiliang Yuan <yuanql9@chinatelecom.cn>
Signed-off-by: Jing Wu <realwujing@gmail.com>
---
 kernel/cgroup/cpuset.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 5c33ab20cc208..80f43a24d3c8a 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1347,17 +1347,36 @@ static void cpuset_update_sd_hk_unlock(void)
 		rebuild_sched_domains_locked();
 
 	if (update_housekeeping) {
+		static const unsigned long noise_types =
+			BIT(HK_TYPE_KERNEL_NOISE) | BIT(HK_TYPE_MANAGED_IRQ);
+
 		update_housekeeping = false;
 		cpumask_copy(isolated_hk_cpus, isolated_cpus);
 
+		mutex_unlock(&cpuset_mutex);
+		cpus_read_unlock();
+
 		/*
 		 * housekeeping_update() is now called without holding
 		 * cpus_read_lock and cpuset_mutex. Only cpuset_top_mutex
 		 * is still being held for mutual exclusion.
 		 */
-		mutex_unlock(&cpuset_mutex);
-		cpus_read_unlock();
+
+		/*
+		 * Update the sched domain mask first; it must succeed
+		 * before the kernel-noise types because workqueue flush
+		 * and timer migration depend on the sched domain mask.
+		 */
 		WARN_ON_ONCE(housekeeping_update(isolated_hk_cpus));
+
+		/*
+		 * Update the kernel-noise housekeeping masks
+		 * (HK_TYPE_KERNEL_NOISE and HK_TYPE_MANAGED_IRQ).  The tick,
+		 * RCU and managed-interrupt state is reconfigured as the
+		 * affected CPUs are cycled through the CPU hotplug machinery.
+		 */
+		WARN_ON_ONCE(housekeeping_update_types(noise_types,
+						       isolated_hk_cpus));
 		mutex_unlock(&cpuset_top_mutex);
 	} else {
 		cpuset_full_unlock();

-- 
2.43.0