From: Linus Torvalds Date: Mon, 30 Aug 2021 21:10:07 +0000 (-0700) Subject: Merge tag 'smp-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git... X-Git-Tag: microblaze-v5.16~197 X-Git-Url: http://git.monstr.eu/?p=linux-2.6-microblaze.git;a=commitdiff_plain;h=08403e2174c4ac8b23922b5b7abe670129f8acb5;hp=e4c3562e1bc79f912457cb062cd0c147026d4a1e Merge tag 'smp-core-2021-08-30' of git://git./linux/kernel/git/tip/tip Pull SMP core updates from Thomas Gleixner: - Replace get/put_online_cpus() in various places. The final removal will happen shortly before v5.15-rc1 when the rest of the patches have been merged. - Add debug code to help the analysis of CPU hotplug failures - A set of kernel doc updates * tag 'smp-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: mm: Replace deprecated CPU-hotplug functions. md/raid5: Replace deprecated CPU-hotplug functions. Documentation: Replace deprecated CPU-hotplug functions. smp: Fix all kernel-doc warnings cpu/hotplug: Add debug printks for hotplug callback failures cpu/hotplug: Use DEVICE_ATTR_*() macro cpu/hotplug: Eliminate all kernel-doc warnings cpu/hotplug: Fix kernel doc warnings for __cpuhp_setup_state_cpuslocked() cpu/hotplug: Fix comment typo smpboot: Replace deprecated CPU-hotplug functions. --- diff --git a/Documentation/core-api/cpu_hotplug.rst b/Documentation/core-api/cpu_hotplug.rst index a2c96bec5ee8..1122cd3044c0 100644 --- a/Documentation/core-api/cpu_hotplug.rst +++ b/Documentation/core-api/cpu_hotplug.rst @@ -220,7 +220,7 @@ goes online (offline) and during initial setup (shutdown) of the driver. However each registration and removal function is also available with a ``_nocalls`` suffix which does not invoke the provided callbacks if the invocation of the callbacks is not desired. During the manual setup (or teardown) the functions -``get_online_cpus()`` and ``put_online_cpus()`` should be used to inhibit CPU +``cpus_read_lock()`` and ``cpus_read_unlock()`` should be used to inhibit CPU hotplug operations. diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index cfc81e98e0b8..4e5b26f03d5b 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -2762,7 +2762,7 @@ listed in: put_prev_task_idle kmem_cache_create pick_next_task_rt - get_online_cpus + cpus_read_lock pick_next_task_fair mutex_lock [...] diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index b8436e4930ed..02ed53b20654 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2437,7 +2437,7 @@ static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors) conf->scribble_sectors >= new_sectors) return 0; mddev_suspend(conf->mddev); - get_online_cpus(); + cpus_read_lock(); for_each_present_cpu(cpu) { struct raid5_percpu *percpu; @@ -2449,7 +2449,7 @@ static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors) break; } - put_online_cpus(); + cpus_read_unlock(); mddev_resume(conf->mddev); if (!err) { conf->scribble_disks = new_disks; diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index f39b34b13871..6ac543d33b66 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -399,7 +399,7 @@ static inline int cpuhp_state_remove_instance(enum cpuhp_state state, /** * cpuhp_state_remove_instance_nocalls - Remove hotplug instance from state - * without invoking the reatdown callback + * without invoking the teardown callback * @state: The state from which the instance is removed * @node: The node for this individual state. * diff --git a/kernel/cpu.c b/kernel/cpu.c index 804b847912dc..192e43a87407 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -41,14 +41,19 @@ #include "smpboot.h" /** - * cpuhp_cpu_state - Per cpu hotplug state storage + * struct cpuhp_cpu_state - Per cpu hotplug state storage * @state: The current cpu state * @target: The target state + * @fail: Current CPU hotplug callback state * @thread: Pointer to the hotplug thread * @should_run: Thread should execute * @rollback: Perform a rollback * @single: Single callback invocation * @bringup: Single callback bringup or teardown selector + * @cpu: CPU number + * @node: Remote CPU node; for multi-instance, do a + * single entry callback for install/remove + * @last: For multi-instance rollback, remember how far we got * @cb_state: The state for a single callback (install/uninstall) * @result: Result of the operation * @done_up: Signal completion to the issuer of the task for cpu-up @@ -106,11 +111,12 @@ static inline void cpuhp_lock_release(bool bringup) { } #endif /** - * cpuhp_step - Hotplug state machine step + * struct cpuhp_step - Hotplug state machine step * @name: Name of the step * @startup: Startup function of the step * @teardown: Teardown function of the step * @cant_stop: Bringup/teardown can't be stopped at this step + * @multi_instance: State has multiple instances which get added afterwards */ struct cpuhp_step { const char *name; @@ -124,7 +130,9 @@ struct cpuhp_step { int (*multi)(unsigned int cpu, struct hlist_node *node); } teardown; + /* private: */ struct hlist_head list; + /* public: */ bool cant_stop; bool multi_instance; }; @@ -143,7 +151,7 @@ static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step) } /** - * cpuhp_invoke_callback _ Invoke the callbacks for a given state + * cpuhp_invoke_callback - Invoke the callbacks for a given state * @cpu: The cpu for which the callback should be invoked * @state: The state to do callbacks for * @bringup: True if the bringup callback should be invoked @@ -151,6 +159,8 @@ static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step) * @lastp: For multi-instance rollback, remember how far we got * * Called from cpu hotplug and from the state register machinery. + * + * Return: %0 on success or a negative errno code */ static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, bool bringup, struct hlist_node *node, @@ -682,6 +692,10 @@ static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, ret = cpuhp_invoke_callback_range(true, cpu, st, target); if (ret) { + pr_debug("CPU UP failed (%d) CPU %u state %s (%d)\n", + ret, cpu, cpuhp_get_step(st->state)->name, + st->state); + cpuhp_reset_state(st, prev_state); if (can_rollback_cpu(st)) WARN_ON(cpuhp_invoke_callback_range(false, cpu, st, @@ -1081,6 +1095,9 @@ static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, ret = cpuhp_invoke_callback_range(false, cpu, st, target); if (ret) { + pr_debug("CPU DOWN failed (%d) CPU %u state %s (%d)\n", + ret, cpu, cpuhp_get_step(st->state)->name, + st->state); cpuhp_reset_state(st, prev_state); @@ -1183,6 +1200,8 @@ static int cpu_down(unsigned int cpu, enum cpuhp_state target) * This function is meant to be used by device core cpu subsystem only. * * Other subsystems should use remove_cpu() instead. + * + * Return: %0 on success or a negative errno code */ int cpu_device_down(struct device *dev) { @@ -1395,6 +1414,8 @@ out: * This function is meant to be used by device core cpu subsystem only. * * Other subsystems should use add_cpu() instead. + * + * Return: %0 on success or a negative errno code */ int cpu_device_up(struct device *dev) { @@ -1420,6 +1441,8 @@ EXPORT_SYMBOL_GPL(add_cpu); * On some architectures like arm64, we can hibernate on any CPU, but on * wake up the CPU we hibernated on might be offline as a side effect of * using maxcpus= for example. + * + * Return: %0 on success or a negative errno code */ int bringup_hibernate_cpu(unsigned int sleep_cpu) { @@ -1976,6 +1999,7 @@ EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); /** * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state * @state: The state to setup + * @name: Name of the step * @invoke: If true, the startup function is invoked for cpus where * cpu state >= @state * @startup: startup callback function @@ -1984,9 +2008,9 @@ EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); * added afterwards. * * The caller needs to hold cpus read locked while calling this function. - * Returns: + * Return: * On success: - * Positive state number if @state is CPUHP_AP_ONLINE_DYN + * Positive state number if @state is CPUHP_AP_ONLINE_DYN; * 0 for all other states * On failure: proper (negative) error code */ @@ -2232,18 +2256,17 @@ int cpuhp_smt_enable(void) #endif #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) -static ssize_t show_cpuhp_state(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t state_show(struct device *dev, + struct device_attribute *attr, char *buf) { struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); return sprintf(buf, "%d\n", st->state); } -static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); +static DEVICE_ATTR_RO(state); -static ssize_t write_cpuhp_target(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t count) +static ssize_t target_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) { struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); struct cpuhp_step *sp; @@ -2281,19 +2304,17 @@ out: return ret ? ret : count; } -static ssize_t show_cpuhp_target(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t target_show(struct device *dev, + struct device_attribute *attr, char *buf) { struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); return sprintf(buf, "%d\n", st->target); } -static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); - +static DEVICE_ATTR_RW(target); -static ssize_t write_cpuhp_fail(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t count) +static ssize_t fail_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) { struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); struct cpuhp_step *sp; @@ -2342,15 +2363,15 @@ static ssize_t write_cpuhp_fail(struct device *dev, return count; } -static ssize_t show_cpuhp_fail(struct device *dev, - struct device_attribute *attr, char *buf) +static ssize_t fail_show(struct device *dev, + struct device_attribute *attr, char *buf) { struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); return sprintf(buf, "%d\n", st->fail); } -static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); +static DEVICE_ATTR_RW(fail); static struct attribute *cpuhp_cpu_attrs[] = { &dev_attr_state.attr, @@ -2365,7 +2386,7 @@ static const struct attribute_group cpuhp_cpu_attr_group = { NULL }; -static ssize_t show_cpuhp_states(struct device *dev, +static ssize_t states_show(struct device *dev, struct device_attribute *attr, char *buf) { ssize_t cur, res = 0; @@ -2384,7 +2405,7 @@ static ssize_t show_cpuhp_states(struct device *dev, mutex_unlock(&cpuhp_state_mutex); return res; } -static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); +static DEVICE_ATTR_RO(states); static struct attribute *cpuhp_cpu_root_attrs[] = { &dev_attr_states.attr, @@ -2457,28 +2478,27 @@ static const char *smt_states[] = { [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", }; -static ssize_t -show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) +static ssize_t control_show(struct device *dev, + struct device_attribute *attr, char *buf) { const char *state = smt_states[cpu_smt_control]; return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); } -static ssize_t -store_smt_control(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count) +static ssize_t control_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) { return __store_smt_control(dev, attr, buf, count); } -static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); +static DEVICE_ATTR_RW(control); -static ssize_t -show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) +static ssize_t active_show(struct device *dev, + struct device_attribute *attr, char *buf) { return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); } -static DEVICE_ATTR(active, 0444, show_smt_active, NULL); +static DEVICE_ATTR_RO(active); static struct attribute *cpuhp_smt_attrs[] = { &dev_attr_control.attr, diff --git a/kernel/smp.c b/kernel/smp.c index 52bf159ec400..f43ede0ab183 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -764,7 +764,7 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info, EXPORT_SYMBOL(smp_call_function_single); /** - * smp_call_function_single_async(): Run an asynchronous function on a + * smp_call_function_single_async() - Run an asynchronous function on a * specific CPU. * @cpu: The CPU to run on. * @csd: Pre-allocated and setup data structure @@ -783,6 +783,8 @@ EXPORT_SYMBOL(smp_call_function_single); * * NOTE: Be careful, there is unfortunately no current debugging facility to * validate the correctness of this serialization. + * + * Return: %0 on success or negative errno value on error */ int smp_call_function_single_async(int cpu, struct __call_single_data *csd) { @@ -974,7 +976,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask, * @mask: The set of cpus to run on (only runs on online subset). * @func: The function to run. This must be fast and non-blocking. * @info: An arbitrary pointer to pass to the function. - * @flags: Bitmask that controls the operation. If %SCF_WAIT is set, wait + * @wait: Bitmask that controls the operation. If %SCF_WAIT is set, wait * (atomically) until function has completed on other CPUs. If * %SCF_RUN_LOCAL is set, the function will also be run locally * if the local CPU is set in the @cpumask. @@ -1180,7 +1182,13 @@ void wake_up_all_idle_cpus(void) EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus); /** - * smp_call_on_cpu - Call a function on a specific cpu + * struct smp_call_on_cpu_struct - Call a function on a specific CPU + * @work: &work_struct + * @done: &completion to signal + * @func: function to call + * @data: function's data argument + * @ret: return value from @func + * @cpu: target CPU (%-1 for any CPU) * * Used to call a function on a specific cpu and wait for it to return. * Optionally make sure the call is done on a specified physical cpu via vcpu diff --git a/kernel/smpboot.c b/kernel/smpboot.c index cf6acab78538..f6bc0bc8a2aa 100644 --- a/kernel/smpboot.c +++ b/kernel/smpboot.c @@ -291,7 +291,7 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread) unsigned int cpu; int ret = 0; - get_online_cpus(); + cpus_read_lock(); mutex_lock(&smpboot_threads_lock); for_each_online_cpu(cpu) { ret = __smpboot_create_thread(plug_thread, cpu); @@ -304,7 +304,7 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread) list_add(&plug_thread->list, &hotplug_threads); out: mutex_unlock(&smpboot_threads_lock); - put_online_cpus(); + cpus_read_unlock(); return ret; } EXPORT_SYMBOL_GPL(smpboot_register_percpu_thread); @@ -317,12 +317,12 @@ EXPORT_SYMBOL_GPL(smpboot_register_percpu_thread); */ void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread) { - get_online_cpus(); + cpus_read_lock(); mutex_lock(&smpboot_threads_lock); list_del(&plug_thread->list); smpboot_destroy_threads(plug_thread); mutex_unlock(&smpboot_threads_lock); - put_online_cpus(); + cpus_read_unlock(); } EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread); diff --git a/mm/swap_slots.c b/mm/swap_slots.c index a66f3e0ec973..16f706c55d92 100644 --- a/mm/swap_slots.c +++ b/mm/swap_slots.c @@ -70,9 +70,9 @@ void disable_swap_slots_cache_lock(void) swap_slot_cache_enabled = false; if (swap_slot_cache_initialized) { /* serialize with cpu hotplug operations */ - get_online_cpus(); + cpus_read_lock(); __drain_swap_slots_cache(SLOTS_CACHE|SLOTS_CACHE_RET); - put_online_cpus(); + cpus_read_unlock(); } } diff --git a/mm/vmstat.c b/mm/vmstat.c index b0534e068166..a7ed56ac4c0b 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -129,9 +129,9 @@ static void sum_vm_events(unsigned long *ret) */ void all_vm_events(unsigned long *ret) { - get_online_cpus(); + cpus_read_lock(); sum_vm_events(ret); - put_online_cpus(); + cpus_read_unlock(); } EXPORT_SYMBOL_GPL(all_vm_events); @@ -1948,7 +1948,7 @@ static void vmstat_shepherd(struct work_struct *w) { int cpu; - get_online_cpus(); + cpus_read_lock(); /* Check processors whose vmstat worker threads have been disabled */ for_each_online_cpu(cpu) { struct delayed_work *dw = &per_cpu(vmstat_work, cpu); @@ -1958,7 +1958,7 @@ static void vmstat_shepherd(struct work_struct *w) cond_resched(); } - put_online_cpus(); + cpus_read_unlock(); schedule_delayed_work(&shepherd, round_jiffies_relative(sysctl_stat_interval)); @@ -2037,9 +2037,9 @@ void __init init_mm_internals(void) if (ret < 0) pr_err("vmstat: failed to register 'online' hotplug state\n"); - get_online_cpus(); + cpus_read_lock(); init_cpu_node_state(); - put_online_cpus(); + cpus_read_unlock(); start_shepherd_timer(); #endif