Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull smp hotplug updates from Thomas Gleixner:
 "This is the next part of the hotplug rework.

   - Convert all notifiers with a priority assigned

   - Convert all CPU_STARTING/DYING notifiers

     The final removal of the STARTING/DYING infrastructure will happen
     when the merge window closes.

  Another 700 hundred line of unpenetrable maze gone :)"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
  timers/core: Correct callback order during CPU hot plug
  leds/trigger/cpu: Move from CPU_STARTING to ONLINE level
  powerpc/numa: Convert to hotplug state machine
  arm/perf: Fix hotplug state machine conversion
  irqchip/armada: Avoid unused function warnings
  ARC/time: Convert to hotplug state machine
  clocksource/atlas7: Convert to hotplug state machine
  clocksource/armada-370-xp: Convert to hotplug state machine
  clocksource/exynos_mct: Convert to hotplug state machine
  clocksource/arm_global_timer: Convert to hotplug state machine
  rcu: Convert rcutree to hotplug state machine
  KVM/arm/arm64/vgic-new: Convert to hotplug state machine
  smp/cfd: Convert core to hotplug state machine
  x86/x2apic: Convert to CPU hotplug state machine
  profile: Convert to hotplug state machine
  timers/core: Convert to hotplug state machine
  hrtimer: Convert to hotplug state machine
  x86/tboot: Convert to hotplug state machine
  arm64/armv8 deprecated: Convert to hotplug state machine
  hwtracing/coresight-etm4x: Convert to hotplug state machine
  ...

1 files changed, 66 insertions, 0 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 7b61887f7ccd..341bf80f80bd 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -517,6 +517,13 @@ static int cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state,
         if (!cpu_online(cpu))
                 return 0;
 
+        /*
+         * If we are up and running, use the hotplug thread. For early calls
+         * we invoke the thread function directly.
+         */
+        if (!st->thread)
+                return cpuhp_invoke_callback(cpu, state, cb);
+
         st->cb_state = state;
         st->cb = cb;
         /*
@@ -1173,6 +1180,31 @@ static struct cpuhp_step cpuhp_bp_states[] = {
                 .teardown               = NULL,
                 .cant_stop              = true,
         },
+        [CPUHP_PERF_PREPARE] = {
+                .name = "perf prepare",
+                .startup = perf_event_init_cpu,
+                .teardown = perf_event_exit_cpu,
+        },
+        [CPUHP_WORKQUEUE_PREP] = {
+                .name = "workqueue prepare",
+                .startup = workqueue_prepare_cpu,
+                .teardown = NULL,
+        },
+        [CPUHP_HRTIMERS_PREPARE] = {
+                .name = "hrtimers prepare",
+                .startup = hrtimers_prepare_cpu,
+                .teardown = hrtimers_dead_cpu,
+        },
+        [CPUHP_SMPCFD_PREPARE] = {
+                .name = "SMPCFD prepare",
+                .startup = smpcfd_prepare_cpu,
+                .teardown = smpcfd_dead_cpu,
+        },
+        [CPUHP_RCUTREE_PREP] = {
+                .name = "RCU-tree prepare",
+                .startup = rcutree_prepare_cpu,
+                .teardown = rcutree_dead_cpu,
+        },
         /*
          * Preparatory and dead notifiers. Will be replaced once the notifiers
          * are converted to states.
@@ -1184,6 +1216,16 @@ static struct cpuhp_step cpuhp_bp_states[] = {
                 .skip_onerr             = true,
                 .cant_stop              = true,
         },
+        /*
+         * On the tear-down path, timers_dead_cpu() must be invoked
+         * before blk_mq_queue_reinit_notify() from notify_dead(),
+         * otherwise a RCU stall occurs.
+         */
+        [CPUHP_TIMERS_DEAD] = {
+                .name = "timers dead",
+                .startup = NULL,
+                .teardown = timers_dead_cpu,
+        },
         /* Kicks the plugged cpu into life */
         [CPUHP_BRINGUP_CPU] = {
                 .name                   = "cpu:bringup",
@@ -1191,6 +1233,10 @@ static struct cpuhp_step cpuhp_bp_states[] = {
                 .teardown               = NULL,
                 .cant_stop              = true,
         },
+        [CPUHP_AP_SMPCFD_DYING] = {
+                .startup = NULL,
+                .teardown = smpcfd_dying_cpu,
+        },
         /*
          * Handled on controll processor until the plugged processor manages
          * this itself.
@@ -1227,6 +1273,10 @@ static struct cpuhp_step cpuhp_ap_states[] = {
                 .startup                = sched_cpu_starting,
                 .teardown               = sched_cpu_dying,
         },
+        [CPUHP_AP_RCUTREE_DYING] = {
+                .startup = NULL,
+                .teardown = rcutree_dying_cpu,
+        },
         /*
          * Low level startup/teardown notifiers. Run with interrupts
          * disabled. Will be removed once the notifiers are converted to
@@ -1250,6 +1300,22 @@ static struct cpuhp_step cpuhp_ap_states[] = {
                 .startup                = smpboot_unpark_threads,
                 .teardown               = NULL,
         },
+        [CPUHP_AP_PERF_ONLINE] = {
+                .name = "perf online",
+                .startup = perf_event_init_cpu,
+                .teardown = perf_event_exit_cpu,
+        },
+        [CPUHP_AP_WORKQUEUE_ONLINE] = {
+                .name = "workqueue online",
+                .startup = workqueue_online_cpu,
+                .teardown = workqueue_offline_cpu,
+        },
+        [CPUHP_AP_RCUTREE_ONLINE] = {
+                .name = "RCU-tree online",
+                .startup = rcutree_online_cpu,
+                .teardown = rcutree_offline_cpu,
+        },
+
         /*
          * Online/down_prepare notifiers. Will be removed once the notifiers
          * are converted to states.