rcu: Standardize explicit CPU-hotplug calls
authorFrederic Weisbecker <frederic@kernel.org>
Fri, 8 Sep 2023 20:36:01 +0000 (22:36 +0200)
committerFrederic Weisbecker <frederic@kernel.org>
Wed, 4 Oct 2023 20:29:45 +0000 (22:29 +0200)
rcu_report_dead() and rcutree_migrate_callbacks() have their headers in
rcupdate.h while those are pure rcutree calls, like the other CPU-hotplug
functions.

Also rcu_cpu_starting() and rcu_report_dead() have different naming
conventions while they mirror each other's effects.

Fix the headers and propose a naming that relates both functions and
aligns with the prefix of other rcutree CPU-hotplug functions.

Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
15 files changed:
Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst
Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp-fqs.svg
Documentation/RCU/Design/Memory-Ordering/TreeRCU-gp.svg
Documentation/RCU/Design/Memory-Ordering/TreeRCU-hotplug.svg
Documentation/RCU/Design/Requirements/Requirements.rst
arch/arm64/kernel/smp.c
arch/powerpc/kernel/smp.c
arch/s390/kernel/smp.c
arch/x86/kernel/smpboot.c
include/linux/interrupt.h
include/linux/rcupdate.h
include/linux/rcutiny.h
include/linux/rcutree.h
kernel/cpu.c
kernel/rcu/tree.c

index 93d899d532584003a5480b28ad823f1f76940b0c..414f8a2012d684cdd42a0e1386f605746b51b49b 100644 (file)
@@ -181,7 +181,7 @@ operations is carried out at several levels:
    of this wait (or series of waits, as the case may be) is to permit a
    concurrent CPU-hotplug operation to complete.
 #. In the case of RCU-sched, one of the last acts of an outgoing CPU is
-   to invoke ``rcu_report_dead()``, which reports a quiescent state for
+   to invoke ``rcutree_report_cpu_dead()``, which reports a quiescent state for
    that CPU. However, this is likely paranoia-induced redundancy.
 
 +-----------------------------------------------------------------------+
index 7ddc094d7f28f57a2905dd8f95098bb7fd61e5fc..d82a77d03d8cc94aaeae53d4b124eda15917c1af 100644 (file)
        font-weight="bold"
        font-size="192"
        id="text202-7-5-3-27-6-5"
-       style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcu_report_dead()</text>
+       style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcutree_report_cpu_dead()</text>
     <text
        xml:space="preserve"
        x="3745.7725"
        font-style="normal"
        y="3679.27"
        x="-3804.9949"
-       xml:space="preserve">rcu_cpu_starting()</text>
+       xml:space="preserve">rcutree_report_cpu_starting()</text>
     <g
        style="fill:none;stroke-width:0.025in"
        id="g3107-7-5-0"
index 069f6f8371c20f64b72c9dfc11f567b9cb5a35ee..6e690a3be16159f4548719cce16d5b69141cab14 100644 (file)
          font-weight="bold"
          font-size="192"
          id="text202-7-5-3-27-6-5"
-         style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcu_report_dead()</text>
+         style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcutree_report_cpu_dead()</text>
       <text
          xml:space="preserve"
          x="3745.7725"
          font-style="normal"
          y="3679.27"
          x="-3804.9949"
-         xml:space="preserve">rcu_cpu_starting()</text>
+         xml:space="preserve">rcutree_report_cpu_starting()</text>
       <g
          style="fill:none;stroke-width:0.025in"
          id="g3107-7-5-0"
index 2c9310ba29bad93e27b9e0efc63888854a12c8f1..4fa7506082bfecd6628dcd791c829c6ab80216b6 100644 (file)
        font-weight="bold"
        font-size="192"
        id="text202-7-5-3-27-6"
-       style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcu_report_dead()</text>
+       style="font-size:192px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;stroke-width:0.025in;font-family:Courier">rcutree_report_cpu_dead()</text>
     <text
        xml:space="preserve"
        x="3745.7725"
        font-style="normal"
        y="3679.27"
        x="-3804.9949"
-       xml:space="preserve">rcu_cpu_starting()</text>
+       xml:space="preserve">rcutree_report_cpu_starting()</text>
     <g
        style="fill:none;stroke-width:0.025in"
        id="g3107-7-5-0"
index f3b605285a87160f6471b5068f1e5de96c3b0e9a..cccafdaa1f849d1171d1cd89311a178260c0af61 100644 (file)
@@ -1955,12 +1955,12 @@ if offline CPUs block an RCU grace period for too long.
 
 An offline CPU's quiescent state will be reported either:
 
-1.  As the CPU goes offline using RCU's hotplug notifier (rcu_report_dead()).
+1.  As the CPU goes offline using RCU's hotplug notifier (rcutree_report_cpu_dead()).
 2.  When grace period initialization (rcu_gp_init()) detects a
     race either with CPU offlining or with a task unblocking on a leaf
     ``rcu_node`` structure whose CPUs are all offline.
 
-The CPU-online path (rcu_cpu_starting()) should never need to report
+The CPU-online path (rcutree_report_cpu_starting()) should never need to report
 a quiescent state for an offline CPU.  However, as a debugging measure,
 it does emit a warning if a quiescent state was not already reported
 for that CPU.
index 8fa646c90c67ea7e06080b2ee94cf066803af534..196533c362e1bdd9a09ad3f6d7acdf32d5aacfe0 100644 (file)
@@ -215,7 +215,7 @@ asmlinkage notrace void secondary_start_kernel(void)
        if (system_uses_irq_prio_masking())
                init_gic_priority_masking();
 
-       rcu_cpu_starting(cpu);
+       rcutree_report_cpu_starting(cpu);
        trace_hardirqs_off();
 
        /*
@@ -401,7 +401,7 @@ void __noreturn cpu_die_early(void)
 
        /* Mark this CPU absent */
        set_cpu_present(cpu, 0);
-       rcu_report_dead();
+       rcutree_report_cpu_dead();
 
        if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
                update_cpu_boot_status(CPU_KILL_ME);
index 5826f5108a12443c6ff148a422b00ee4900184aa..a30d4d93ff0b043a4716d071ede0fc1585d33a00 100644 (file)
@@ -1629,7 +1629,7 @@ void start_secondary(void *unused)
 
        smp_store_cpu_info(cpu);
        set_dec(tb_ticks_per_jiffy);
-       rcu_cpu_starting(cpu);
+       rcutree_report_cpu_starting(cpu);
        cpu_callin_map[cpu] = 1;
 
        if (smp_ops->setup_cpu)
index a4edb7ea66ea763d9090844446b2a2d7566d74ef..214a1b67f80a9506beb2b35b530d2fc365c44c70 100644 (file)
@@ -898,7 +898,7 @@ static void smp_start_secondary(void *cpuvoid)
        S390_lowcore.restart_flags = 0;
        restore_access_regs(S390_lowcore.access_regs_save_area);
        cpu_init();
-       rcu_cpu_starting(cpu);
+       rcutree_report_cpu_starting(cpu);
        init_cpu_timer();
        vtime_init();
        vdso_getcpu_init();
index 4e45ff44aa07db38e6d765605e6f12b80fe3f08d..4ccb76f89af847bdecd4d0b5fc2c4fab759b4c4d 100644 (file)
@@ -288,7 +288,7 @@ static void notrace start_secondary(void *unused)
 
        cpu_init();
        fpu__init_cpu();
-       rcu_cpu_starting(raw_smp_processor_id());
+       rcutree_report_cpu_starting(raw_smp_processor_id());
        x86_cpuinit.early_percpu_clock_init();
 
        ap_starting();
index a92bce40b04b3a0352534f76334faec42d85fbb1..d05e1e9a553c3d81826c4a3d66aafb059dbe82ef 100644 (file)
@@ -566,7 +566,7 @@ enum
  *
  * _ RCU:
  *     1) rcutree_migrate_callbacks() migrates the queue.
- *     2) rcu_report_dead() reports the final quiescent states.
+ *     2) rcutree_report_cpu_dead() reports the final quiescent states.
  *
  * _ IRQ_POLL: irq_poll_cpu_dead() migrates the queue
  */
index aa351ddcbe8d79deca90b0b4be424cd4ff049696..f7206b2623c98c16ed02d73ac77774f43d5cbe37 100644 (file)
@@ -122,8 +122,6 @@ static inline void call_rcu_hurry(struct rcu_head *head, rcu_callback_t func)
 void rcu_init(void);
 extern int rcu_scheduler_active;
 void rcu_sched_clock_irq(int user);
-void rcu_report_dead(void);
-void rcutree_migrate_callbacks(int cpu);
 
 #ifdef CONFIG_TASKS_RCU_GENERIC
 void rcu_init_tasks_generic(void);
index 7b949292908a917b9a152267f987ac728d7ef10f..d9ac7b136aeab2379eb5f7656e3319607d335cc1 100644 (file)
@@ -171,6 +171,6 @@ static inline void rcu_all_qs(void) { barrier(); }
 #define rcutree_offline_cpu      NULL
 #define rcutree_dead_cpu         NULL
 #define rcutree_dying_cpu        NULL
-static inline void rcu_cpu_starting(unsigned int cpu) { }
+static inline void rcutree_report_cpu_starting(unsigned int cpu) { }
 
 #endif /* __LINUX_RCUTINY_H */
index 46875c4e9f56a07a67dfa6abbe2e957d1a2abf59..254244202ea9764d40f59733d900b5644c189381 100644 (file)
@@ -110,7 +110,7 @@ void rcu_all_qs(void);
 /* RCUtree hotplug events */
 int rcutree_prepare_cpu(unsigned int cpu);
 int rcutree_online_cpu(unsigned int cpu);
-void rcu_cpu_starting(unsigned int cpu);
+void rcutree_report_cpu_starting(unsigned int cpu);
 
 #ifdef CONFIG_HOTPLUG_CPU
 int rcutree_dead_cpu(unsigned int cpu);
@@ -122,4 +122,9 @@ int rcutree_offline_cpu(unsigned int cpu);
 #define rcutree_offline_cpu NULL
 #endif
 
+void rcutree_migrate_callbacks(int cpu);
+
+/* Called from hotplug and also arm64 early secondary boot failure */
+void rcutree_report_cpu_dead(void);
+
 #endif /* __LINUX_RCUTREE_H */
index 076e75fed8bb05100e20c1df8806ab5bc27d2032..2491766e1fd59ffe7b657a4239efa6aa4f8f7b35 100644 (file)
@@ -1388,10 +1388,10 @@ void cpuhp_report_idle_dead(void)
        struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
 
        BUG_ON(st->state != CPUHP_AP_OFFLINE);
-       rcu_report_dead();
+       rcutree_report_cpu_dead();
        st->state = CPUHP_AP_IDLE_DEAD;
        /*
-        * We cannot call complete after rcu_report_dead() so we delegate it
+        * We cannot call complete after rcutree_report_cpu_dead() so we delegate it
         * to an online cpu.
         */
        smp_call_function_single(cpumask_first(cpu_online_mask),
@@ -1617,7 +1617,7 @@ void notify_cpu_starting(unsigned int cpu)
        struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
        enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
 
-       rcu_cpu_starting(cpu);  /* Enables RCU usage on this CPU. */
+       rcutree_report_cpu_starting(cpu);       /* Enables RCU usage on this CPU. */
        cpumask_set_cpu(cpu, &cpus_booted_once_mask);
 
        /*
index f9c6b2680cbb5959ad512b699d31aeeba900375b..36d8818eaec1a44318d2b428f0deed6806caae6a 100644 (file)
@@ -4216,7 +4216,7 @@ bool rcu_lockdep_current_cpu_online(void)
        rdp = this_cpu_ptr(&rcu_data);
        /*
         * Strictly, we care here about the case where the current CPU is
-        * in rcu_cpu_starting() and thus has an excuse for rdp->grpmask
+        * in rcutree_report_cpu_starting() and thus has an excuse for rdp->grpmask
         * not being up to date. So arch_spin_is_locked() might have a
         * false positive if it's held by some *other* CPU, but that's
         * OK because that just means a false *negative* on the warning.
@@ -4445,8 +4445,10 @@ int rcutree_online_cpu(unsigned int cpu)
  * from the incoming CPU rather than from the cpuhp_step mechanism.
  * This is because this function must be invoked at a precise location.
  * This incoming CPU must not have enabled interrupts yet.
+ *
+ * This mirrors the effects of rcutree_report_cpu_dead().
  */
-void rcu_cpu_starting(unsigned int cpu)
+void rcutree_report_cpu_starting(unsigned int cpu)
 {
        unsigned long mask;
        struct rcu_data *rdp;
@@ -4500,8 +4502,10 @@ void rcu_cpu_starting(unsigned int cpu)
  * Note that this function is special in that it is invoked directly
  * from the outgoing CPU rather than from the cpuhp_step mechanism.
  * This is because this function must be invoked at a precise location.
+ *
+ * This mirrors the effect of rcutree_report_cpu_starting().
  */
-void rcu_report_dead(void)
+void rcutree_report_cpu_dead(void)
 {
        unsigned long flags;
        unsigned long mask;
@@ -5072,7 +5076,7 @@ void __init rcu_init(void)
        pm_notifier(rcu_pm_notify, 0);
        WARN_ON(num_online_cpus() > 1); // Only one CPU this early in boot.
        rcutree_prepare_cpu(cpu);
-       rcu_cpu_starting(cpu);
+       rcutree_report_cpu_starting(cpu);
        rcutree_online_cpu(cpu);
 
        /* Create workqueue for Tree SRCU and for expedited GPs. */