Do we really need so many states here ?
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
include/linux/cpuhotplug.h | 18 ++++++++
kernel/cpu.c | 12 +++++
kernel/rcutree.c | 95 ++++++++++++++++++++-------------------------
3 files changed, 73 insertions(+), 52 deletions(-)
Index: linux-2.6/include/linux/cpuhotplug.h
===================================================================
--- linux-2.6.orig/include/linux/cpuhotplug.h
+++ linux-2.6/include/linux/cpuhotplug.h
@@ -12,6 +12,7 @@ enum cpuhp_states {
CPUHP_PERF_PREPARE,
CPUHP_SCHED_MIGRATE_PREP,
CPUHP_WORKQUEUE_PREP,
+ CPUHP_RCUTREE_PREPARE,
CPUHP_NOTIFY_PREPARE,
CPUHP_NOTIFY_DEAD,
CPUHP_CPUFREQ_DEAD,
@@ -27,6 +28,7 @@ enum cpuhp_states {
CPUHP_AP_ARM64_TIMER_STARTING,
CPUHP_AP_KVM_STARTING,
CPUHP_AP_NOTIFY_DYING,
+ CPUHP_AP_RCUTREE_DYING,
CPUHP_AP_X86_TBOOT_DYING,
CPUHP_AP_S390_VTIME_DYING,
CPUHP_AP_SCHED_NOHZ_DYING,
@@ -39,6 +41,7 @@ enum cpuhp_states {
CPUHP_SCHED_MIGRATE_ONLINE,
CPUHP_WORKQUEUE_ONLINE,
CPUHP_CPUFREQ_ONLINE,
+ CPUHP_RCUTREE_ONLINE,
CPUHP_NOTIFY_ONLINE,
CPUHP_NOTIFY_DOWN_PREPARE,
CPUHP_PERF_X86_UNCORE_ONLINE,
@@ -147,4 +150,19 @@ int workqueue_prepare_cpu(unsigned int c
int workqueue_online_cpu(unsigned int cpu);
int workqueue_offline_cpu(unsigned int cpu);
+/* RCUtree hotplug events */
+#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
+int rcutree_prepare_cpu(unsigned int cpu);
+int rcutree_online_cpu(unsigned int cpu);
+int rcutree_offline_cpu(unsigned int cpu);
+int rcutree_dead_cpu(unsigned int cpu);
+int rcutree_dying_cpu(unsigned int cpu);
+#else
+#define rcutree_prepare_cpu NULL
+#define rcutree_online_cpu NULL
+#define rcutree_offline_cpu NULL
+#define rcutree_dead_cpu NULL
+#define rcutree_dying_cpu NULL
+#endif
+
#endif
Index: linux-2.6/kernel/cpu.c
===================================================================
--- linux-2.6.orig/kernel/cpu.c
+++ linux-2.6/kernel/cpu.c
@@ -755,6 +755,10 @@ static struct cpuhp_step cpuhp_bp_states
.startup = workqueue_prepare_cpu,
.teardown = NULL,
},
+ [CPUHP_RCUTREE_PREPARE] = {
+ .startup = rcutree_prepare_cpu,
+ .teardown = rcutree_dead_cpu,
+ },
[CPUHP_NOTIFY_PREPARE] = {
.startup = notify_prepare,
.teardown = NULL,
@@ -787,6 +791,10 @@ static struct cpuhp_step cpuhp_bp_states
.startup = workqueue_online_cpu,
.teardown = workqueue_offline_cpu,
},
+ [CPUHP_RCUTREE_ONLINE] = {
+ .startup = rcutree_online_cpu,
+ .teardown = rcutree_offline_cpu,
+ },
[CPUHP_NOTIFY_ONLINE] = {
.startup = notify_online,
.teardown = NULL,
@@ -813,6 +821,10 @@ static struct cpuhp_step cpuhp_ap_states
.startup = NULL,
.teardown = notify_dying,
},
+ [CPUHP_AP_RCUTREE_DYING] = {
+ .startup = NULL,
+ .teardown = rcutree_dying_cpu,
+ },
[CPUHP_AP_SCHED_NOHZ_DYING] = {
.startup = NULL,
.teardown = nohz_balance_exit_idle,
Index: linux-2.6/kernel/rcutree.c
===================================================================
--- linux-2.6.orig/kernel/rcutree.c
+++ linux-2.6/kernel/rcutree.c
@@ -2787,67 +2787,59 @@ rcu_init_percpu_data(int cpu, struct rcu
mutex_unlock(&rsp->onoff_mutex);
}
-static void __cpuinit rcu_prepare_cpu(int cpu)
+int __cpuinit rcutree_prepare_cpu(unsigned int cpu)
{
struct rcu_state *rsp;
for_each_rcu_flavor(rsp)
rcu_init_percpu_data(cpu, rsp,
strcmp(rsp->name, "rcu_preempt") == 0);
+ rcu_prepare_kthreads(cpu);
+ return 0;
}
-/*
- * Handle CPU online/offline notification events.
- */
-static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
+int __cpuinit rcutree_dead_cpu(unsigned int cpu)
{
- long cpu = (long)hcpu;
- struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu);
- struct rcu_node *rnp = rdp->mynode;
struct rcu_state *rsp;
- int ret = NOTIFY_OK;
- trace_rcu_utilization("Start CPU hotplug");
- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- rcu_prepare_cpu(cpu);
- rcu_prepare_kthreads(cpu);
- break;
- case CPU_ONLINE:
- case CPU_DOWN_FAILED:
- rcu_boost_kthread_setaffinity(rnp, -1);
- break;
- case CPU_DOWN_PREPARE:
- if (nocb_cpu_expendable(cpu))
- rcu_boost_kthread_setaffinity(rnp, cpu);
- else
- ret = NOTIFY_BAD;
- break;
- case CPU_DYING:
- case CPU_DYING_FROZEN:
- /*
- * The whole machine is "stopped" except this CPU, so we can
- * touch any data without introducing corruption. We send the
- * dying CPU's callbacks to an arbitrarily chosen online CPU.
- */
- for_each_rcu_flavor(rsp)
- rcu_cleanup_dying_cpu(rsp);
- rcu_cleanup_after_idle(cpu);
- break;
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- for_each_rcu_flavor(rsp)
- rcu_cleanup_dead_cpu(cpu, rsp);
- break;
- default:
- break;
- }
- trace_rcu_utilization("End CPU hotplug");
- return ret;
+ for_each_rcu_flavor(rsp)
+ rcu_cleanup_dead_cpu(cpu, rsp);
+ return 0;
+}
+
+static void __cpuinit rcutree_affinity_setting(unsigned int cpu, int outgoing)
+{
+ struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu);
+
+ rcu_boost_kthread_setaffinity(rdp->mynode, outgoing);
+}
+
+int __cpuinit rcutree_online_cpu(unsigned int cpu)
+{
+ rcutree_affinity_setting(cpu, -1);
+ return 0;
+}
+
+int __cpuinit rcutree_offline_cpu(unsigned int cpu)
+{
+ if (!nocb_cpu_expendable(cpu))
+ return -EINVAL;
+ rcutree_affinity_setting(cpu, cpu);
+ return 0;
+}
+
+int __cpuinit rcutree_dying_cpu(unsigned int cpu)
+{
+ struct rcu_state *rsp;
+ /*
+ * The whole machine is "stopped" except this CPU, so we can
+ * touch any data without introducing corruption. We send the
+ * dying CPU's callbacks to an arbitrarily chosen online CPU.
+ */
+ for_each_rcu_flavor(rsp)
+ rcu_cleanup_dying_cpu(rsp);
+ rcu_cleanup_after_idle(cpu);
+ return 0;
}
/*
@@ -3071,9 +3063,8 @@ void __init rcu_init(void)
* this is called early in boot, before either interrupts
* or the scheduler are operational.
*/
- cpu_notifier(rcu_cpu_notify, 0);
for_each_online_cpu(cpu)
- rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
+ rcutree_prepare_cpu(cpu);
check_cpu_stall_init();
}
--
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