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linux-stable/include/linux/cpuhotplug.h
Frederic Weisbecker 3ad6eb0683 tick: Start centralizing tick related CPU hotplug operations 
During the CPU offlining process, the various timer tick features are
shut down from scattered places, sometimes from teardown callbacks on
stop machine, sometimes through explicit calls, sometimes from the
control CPU after the CPU died. The reason why these shutdown operations
are spread around is not always clear and it makes the tick lifecycle
hard to follow.

The tick should be shut down in order from highest to lowest level:

On stop machine from the dying CPU (high-level):

 1) Hand-over the timekeeping duty (tick_handover_do_timer())
 2) Cancel the tick implementation called by the clockevent callback
    (tick_cancel_sched_timer())
 3) Shutdown broadcasting (tick_offline_cpu() / tick_broadcast_offline())

On stop machine from the dying CPU (low-level):

 4) Shutdown clockevents drivers (CPUHP_AP_*_TIMER_STARTING states)

From the control CPU after the CPU died (low-level):

 5) Shutdown/unregister/cleanup clockevents for the dead CPU
    (tick_cleanup_dead_cpu())

Instead the current order is 2, 4 (both from CPU hotplug states), then
1 and 3 through direct calls. This layout and order don't make much
sense. The operations 1, 2, 3 should be gathered together and in order.

Sort this situation with creating a new TICK shut-down CPU hotplug state
and start with introducing the timekeeping duty hand-over there. The
state must precede hrtimers migration because the tick hrtimer will be
stopped from it in a further patch.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240225225508.11587-8-frederic@kernel.org
2024-02-26 11:37:31 +01:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __CPUHOTPLUG_H
#define __CPUHOTPLUG_H
#include <linux/types.h>
/*
* CPU-up CPU-down
*
* BP AP BP AP
*
* OFFLINE OFFLINE
* | ^
* v |
* BRINGUP_CPU->AP_OFFLINE BRINGUP_CPU <- AP_IDLE_DEAD (idle thread/play_dead)
* | AP_OFFLINE
* v (IRQ-off) ,---------------^
* AP_ONLNE | (stop_machine)
* | TEARDOWN_CPU <- AP_ONLINE_IDLE
* | ^
* v |
* AP_ACTIVE AP_ACTIVE
*/
/*
* CPU hotplug states. The state machine invokes the installed state
* startup callbacks sequentially from CPUHP_OFFLINE + 1 to CPUHP_ONLINE
* during a CPU online operation. During a CPU offline operation the
* installed teardown callbacks are invoked in the reverse order from
* CPU_ONLINE - 1 down to CPUHP_OFFLINE.
*
* The state space has three sections: PREPARE, STARTING and ONLINE.
*
* PREPARE: The callbacks are invoked on a control CPU before the
* hotplugged CPU is started up or after the hotplugged CPU has died.
*
* STARTING: The callbacks are invoked on the hotplugged CPU from the low level
* hotplug startup/teardown code with interrupts disabled.
*
* ONLINE: The callbacks are invoked on the hotplugged CPU from the per CPU
* hotplug thread with interrupts and preemption enabled.
*
* Adding explicit states to this enum is only necessary when:
*
* 1) The state is within the STARTING section
*
* 2) The state has ordering constraints vs. other states in the
* same section.
*
* If neither #1 nor #2 apply, please use the dynamic state space when
* setting up a state by using CPUHP_BP_PREPARE_DYN or CPUHP_AP_ONLINE_DYN
* for the @state argument of the setup function.
*
* See Documentation/core-api/cpu_hotplug.rst for further information and
* examples.
*/
enum cpuhp_state {
CPUHP_INVALID = -1,
/* PREPARE section invoked on a control CPU */
CPUHP_OFFLINE = 0,
CPUHP_CREATE_THREADS,
CPUHP_PERF_PREPARE,
CPUHP_PERF_X86_PREPARE,
CPUHP_PERF_X86_AMD_UNCORE_PREP,
CPUHP_PERF_POWER,
CPUHP_PERF_SUPERH,
CPUHP_X86_HPET_DEAD,
CPUHP_X86_MCE_DEAD,
CPUHP_VIRT_NET_DEAD,
CPUHP_IBMVNIC_DEAD,
CPUHP_SLUB_DEAD,
CPUHP_DEBUG_OBJ_DEAD,
CPUHP_MM_WRITEBACK_DEAD,
CPUHP_MM_VMSTAT_DEAD,
CPUHP_SOFTIRQ_DEAD,
CPUHP_NET_MVNETA_DEAD,
CPUHP_CPUIDLE_DEAD,
CPUHP_ARM64_FPSIMD_DEAD,
CPUHP_ARM_OMAP_WAKE_DEAD,
CPUHP_IRQ_POLL_DEAD,
CPUHP_BLOCK_SOFTIRQ_DEAD,
CPUHP_BIO_DEAD,
CPUHP_ACPI_CPUDRV_DEAD,
CPUHP_S390_PFAULT_DEAD,
CPUHP_BLK_MQ_DEAD,
CPUHP_FS_BUFF_DEAD,
CPUHP_PRINTK_DEAD,
CPUHP_MM_MEMCQ_DEAD,
CPUHP_PERCPU_CNT_DEAD,
CPUHP_RADIX_DEAD,
CPUHP_PAGE_ALLOC,
CPUHP_NET_DEV_DEAD,
CPUHP_PCI_XGENE_DEAD,
CPUHP_IOMMU_IOVA_DEAD,
CPUHP_AP_ARM_CACHE_B15_RAC_DEAD,
CPUHP_PADATA_DEAD,
CPUHP_AP_DTPM_CPU_DEAD,
CPUHP_RANDOM_PREPARE,
CPUHP_WORKQUEUE_PREP,
CPUHP_POWER_NUMA_PREPARE,
CPUHP_HRTIMERS_PREPARE,
CPUHP_PROFILE_PREPARE,
CPUHP_X2APIC_PREPARE,
CPUHP_SMPCFD_PREPARE,
CPUHP_RELAY_PREPARE,
CPUHP_MD_RAID5_PREPARE,
CPUHP_RCUTREE_PREP,
CPUHP_CPUIDLE_COUPLED_PREPARE,
CPUHP_POWERPC_PMAC_PREPARE,
CPUHP_POWERPC_MMU_CTX_PREPARE,
CPUHP_XEN_PREPARE,
CPUHP_XEN_EVTCHN_PREPARE,
CPUHP_ARM_SHMOBILE_SCU_PREPARE,
CPUHP_SH_SH3X_PREPARE,
CPUHP_TOPOLOGY_PREPARE,
CPUHP_NET_IUCV_PREPARE,
CPUHP_ARM_BL_PREPARE,
CPUHP_TRACE_RB_PREPARE,
CPUHP_MM_ZS_PREPARE,
CPUHP_MM_ZSWP_POOL_PREPARE,
CPUHP_KVM_PPC_BOOK3S_PREPARE,
CPUHP_ZCOMP_PREPARE,
CPUHP_TIMERS_PREPARE,
CPUHP_MIPS_SOC_PREPARE,
CPUHP_BP_PREPARE_DYN,
CPUHP_BP_PREPARE_DYN_END = CPUHP_BP_PREPARE_DYN + 20,
CPUHP_BP_KICK_AP,
CPUHP_BRINGUP_CPU,
/*
* STARTING section invoked on the hotplugged CPU in low level
* bringup and teardown code.
*/
CPUHP_AP_IDLE_DEAD,
CPUHP_AP_OFFLINE,
CPUHP_AP_CACHECTRL_STARTING,
CPUHP_AP_SCHED_STARTING,
CPUHP_AP_RCUTREE_DYING,
CPUHP_AP_CPU_PM_STARTING,
CPUHP_AP_IRQ_GIC_STARTING,
CPUHP_AP_IRQ_HIP04_STARTING,
CPUHP_AP_IRQ_APPLE_AIC_STARTING,
CPUHP_AP_IRQ_ARMADA_XP_STARTING,
CPUHP_AP_IRQ_BCM2836_STARTING,
CPUHP_AP_IRQ_MIPS_GIC_STARTING,
CPUHP_AP_IRQ_LOONGARCH_STARTING,
CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
CPUHP_AP_ARM_MVEBU_COHERENCY,
CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING,
CPUHP_AP_PERF_X86_STARTING,
CPUHP_AP_PERF_X86_AMD_IBS_STARTING,
CPUHP_AP_PERF_X86_CSTATE_STARTING,
CPUHP_AP_PERF_XTENSA_STARTING,
CPUHP_AP_ARM_VFP_STARTING,
CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING,
CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
CPUHP_AP_PERF_ARM_ACPI_STARTING,
CPUHP_AP_PERF_ARM_STARTING,
CPUHP_AP_PERF_RISCV_STARTING,
CPUHP_AP_ARM_L2X0_STARTING,
CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
CPUHP_AP_ARM_ARCH_TIMER_STARTING,
CPUHP_AP_ARM_ARCH_TIMER_EVTSTRM_STARTING,
CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
CPUHP_AP_JCORE_TIMER_STARTING,
CPUHP_AP_ARM_TWD_STARTING,
CPUHP_AP_QCOM_TIMER_STARTING,
CPUHP_AP_TEGRA_TIMER_STARTING,
CPUHP_AP_ARMADA_TIMER_STARTING,
CPUHP_AP_MIPS_GIC_TIMER_STARTING,
CPUHP_AP_ARC_TIMER_STARTING,
CPUHP_AP_RISCV_TIMER_STARTING,
CPUHP_AP_CLINT_TIMER_STARTING,
CPUHP_AP_CSKY_TIMER_STARTING,
CPUHP_AP_TI_GP_TIMER_STARTING,
CPUHP_AP_HYPERV_TIMER_STARTING,
/* Must be the last timer callback */
CPUHP_AP_DUMMY_TIMER_STARTING,
CPUHP_AP_ARM_XEN_STARTING,
CPUHP_AP_ARM_XEN_RUNSTATE_STARTING,
CPUHP_AP_ARM_CORESIGHT_STARTING,
CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
CPUHP_AP_ARM64_ISNDEP_STARTING,
CPUHP_AP_SMPCFD_DYING,
CPUHP_AP_HRTIMERS_DYING,
CPUHP_AP_TICK_DYING,
CPUHP_AP_X86_TBOOT_DYING,
CPUHP_AP_ARM_CACHE_B15_RAC_DYING,
CPUHP_AP_ONLINE,
CPUHP_TEARDOWN_CPU,
/* Online section invoked on the hotplugged CPU from the hotplug thread */
CPUHP_AP_ONLINE_IDLE,
CPUHP_AP_HYPERV_ONLINE,
CPUHP_AP_KVM_ONLINE,
CPUHP_AP_SCHED_WAIT_EMPTY,
CPUHP_AP_SMPBOOT_THREADS,
CPUHP_AP_IRQ_AFFINITY_ONLINE,
CPUHP_AP_BLK_MQ_ONLINE,
CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS,
CPUHP_AP_X86_INTEL_EPB_ONLINE,
CPUHP_AP_PERF_ONLINE,
CPUHP_AP_PERF_X86_ONLINE,
CPUHP_AP_PERF_X86_UNCORE_ONLINE,
CPUHP_AP_PERF_X86_AMD_UNCORE_ONLINE,
CPUHP_AP_PERF_X86_AMD_POWER_ONLINE,
CPUHP_AP_PERF_X86_RAPL_ONLINE,
CPUHP_AP_PERF_X86_CSTATE_ONLINE,
CPUHP_AP_PERF_S390_CF_ONLINE,
CPUHP_AP_PERF_S390_SF_ONLINE,
CPUHP_AP_PERF_ARM_CCI_ONLINE,
CPUHP_AP_PERF_ARM_CCN_ONLINE,
CPUHP_AP_PERF_ARM_HISI_CPA_ONLINE,
CPUHP_AP_PERF_ARM_HISI_DDRC_ONLINE,
CPUHP_AP_PERF_ARM_HISI_HHA_ONLINE,
CPUHP_AP_PERF_ARM_HISI_L3_ONLINE,
CPUHP_AP_PERF_ARM_HISI_PA_ONLINE,
CPUHP_AP_PERF_ARM_HISI_SLLC_ONLINE,
CPUHP_AP_PERF_ARM_HISI_PCIE_PMU_ONLINE,
CPUHP_AP_PERF_ARM_HNS3_PMU_ONLINE,
CPUHP_AP_PERF_ARM_L2X0_ONLINE,
CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE,
CPUHP_AP_PERF_ARM_APM_XGENE_ONLINE,
CPUHP_AP_PERF_ARM_CAVIUM_TX2_UNCORE_ONLINE,
CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE,
CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE,
CPUHP_AP_PERF_POWERPC_CORE_IMC_ONLINE,
CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE,
CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE,
CPUHP_AP_PERF_POWERPC_HV_24x7_ONLINE,
CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE,
CPUHP_AP_PERF_CSKY_ONLINE,
CPUHP_AP_TMIGR_ONLINE,
CPUHP_AP_WATCHDOG_ONLINE,
CPUHP_AP_WORKQUEUE_ONLINE,
CPUHP_AP_RANDOM_ONLINE,
CPUHP_AP_RCUTREE_ONLINE,
CPUHP_AP_BASE_CACHEINFO_ONLINE,
CPUHP_AP_ONLINE_DYN,
CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 40,
CPUHP_AP_X86_HPET_ONLINE,
CPUHP_AP_X86_KVM_CLK_ONLINE,
CPUHP_AP_ACTIVE,
CPUHP_ONLINE,
};
int __cpuhp_setup_state(enum cpuhp_state state, const char *name, bool invoke,
int (*startup)(unsigned int cpu),
int (*teardown)(unsigned int cpu), bool multi_instance);
int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, const char *name,
bool invoke,
int (*startup)(unsigned int cpu),
int (*teardown)(unsigned int cpu),
bool multi_instance);
/**
* cpuhp_setup_state - Setup hotplug state callbacks with calling the @startup
* callback
* @state: The state for which the calls are installed
* @name: Name of the callback (will be used in debug output)
* @startup: startup callback function or NULL if not required
* @teardown: teardown callback function or NULL if not required
*
* Installs the callback functions and invokes the @startup callback on
* the online cpus which have already reached the @state.
*/
static inline int cpuhp_setup_state(enum cpuhp_state state,
const char *name,
int (*startup)(unsigned int cpu),
int (*teardown)(unsigned int cpu))
{
return __cpuhp_setup_state(state, name, true, startup, teardown, false);
}
/**
* cpuhp_setup_state_cpuslocked - Setup hotplug state callbacks with calling
* @startup callback from a cpus_read_lock()
* held region
* @state: The state for which the calls are installed
* @name: Name of the callback (will be used in debug output)
* @startup: startup callback function or NULL if not required
* @teardown: teardown callback function or NULL if not required
*
* Same as cpuhp_setup_state() except that it must be invoked from within a
* cpus_read_lock() held region.
*/
static inline int cpuhp_setup_state_cpuslocked(enum cpuhp_state state,
const char *name,
int (*startup)(unsigned int cpu),
int (*teardown)(unsigned int cpu))
{
return __cpuhp_setup_state_cpuslocked(state, name, true, startup,
teardown, false);
}
/**
* cpuhp_setup_state_nocalls - Setup hotplug state callbacks without calling the
* @startup callback
* @state: The state for which the calls are installed
* @name: Name of the callback.
* @startup: startup callback function or NULL if not required
* @teardown: teardown callback function or NULL if not required
*
* Same as cpuhp_setup_state() except that the @startup callback is not
* invoked during installation. NOP if SMP=n or HOTPLUG_CPU=n.
*/
static inline int cpuhp_setup_state_nocalls(enum cpuhp_state state,
const char *name,
int (*startup)(unsigned int cpu),
int (*teardown)(unsigned int cpu))
{
return __cpuhp_setup_state(state, name, false, startup, teardown,
false);
}
/**
* cpuhp_setup_state_nocalls_cpuslocked - Setup hotplug state callbacks without
* invoking the @startup callback from
* a cpus_read_lock() held region
* callbacks
* @state: The state for which the calls are installed
* @name: Name of the callback.
* @startup: startup callback function or NULL if not required
* @teardown: teardown callback function or NULL if not required
*
* Same as cpuhp_setup_state_nocalls() except that it must be invoked from
* within a cpus_read_lock() held region.
*/
static inline int cpuhp_setup_state_nocalls_cpuslocked(enum cpuhp_state state,
const char *name,
int (*startup)(unsigned int cpu),
int (*teardown)(unsigned int cpu))
{
return __cpuhp_setup_state_cpuslocked(state, name, false, startup,
teardown, false);
}
/**
* cpuhp_setup_state_multi - Add callbacks for multi state
* @state: The state for which the calls are installed
* @name: Name of the callback.
* @startup: startup callback function or NULL if not required
* @teardown: teardown callback function or NULL if not required
*
* Sets the internal multi_instance flag and prepares a state to work as a multi
* instance callback. No callbacks are invoked at this point. The callbacks are
* invoked once an instance for this state are registered via
* cpuhp_state_add_instance() or cpuhp_state_add_instance_nocalls()
*/
static inline int cpuhp_setup_state_multi(enum cpuhp_state state,
const char *name,
int (*startup)(unsigned int cpu,
struct hlist_node *node),
int (*teardown)(unsigned int cpu,
struct hlist_node *node))
{
return __cpuhp_setup_state(state, name, false,
(void *) startup,
(void *) teardown, true);
}
int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
bool invoke);
int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state,
struct hlist_node *node, bool invoke);
/**
* cpuhp_state_add_instance - Add an instance for a state and invoke startup
* callback.
* @state: The state for which the instance is installed
* @node: The node for this individual state.
*
* Installs the instance for the @state and invokes the registered startup
* callback on the online cpus which have already reached the @state. The
* @state must have been earlier marked as multi-instance by
* cpuhp_setup_state_multi().
*/
static inline int cpuhp_state_add_instance(enum cpuhp_state state,
struct hlist_node *node)
{
return __cpuhp_state_add_instance(state, node, true);
}
/**
* cpuhp_state_add_instance_nocalls - Add an instance for a state without
* invoking the startup callback.
* @state: The state for which the instance is installed
* @node: The node for this individual state.
*
* Installs the instance for the @state. The @state must have been earlier
* marked as multi-instance by cpuhp_setup_state_multi. NOP if SMP=n or
* HOTPLUG_CPU=n.
*/
static inline int cpuhp_state_add_instance_nocalls(enum cpuhp_state state,
struct hlist_node *node)
{
return __cpuhp_state_add_instance(state, node, false);
}
/**
* cpuhp_state_add_instance_nocalls_cpuslocked - Add an instance for a state
* without invoking the startup
* callback from a cpus_read_lock()
* held region.
* @state: The state for which the instance is installed
* @node: The node for this individual state.
*
* Same as cpuhp_state_add_instance_nocalls() except that it must be
* invoked from within a cpus_read_lock() held region.
*/
static inline int
cpuhp_state_add_instance_nocalls_cpuslocked(enum cpuhp_state state,
struct hlist_node *node)
{
return __cpuhp_state_add_instance_cpuslocked(state, node, false);
}
void __cpuhp_remove_state(enum cpuhp_state state, bool invoke);
void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke);
/**
* cpuhp_remove_state - Remove hotplug state callbacks and invoke the teardown
* @state: The state for which the calls are removed
*
* Removes the callback functions and invokes the teardown callback on
* the online cpus which have already reached the @state.
*/
static inline void cpuhp_remove_state(enum cpuhp_state state)
{
__cpuhp_remove_state(state, true);
}
/**
* cpuhp_remove_state_nocalls - Remove hotplug state callbacks without invoking
* the teardown callback
* @state: The state for which the calls are removed
*/
static inline void cpuhp_remove_state_nocalls(enum cpuhp_state state)
{
__cpuhp_remove_state(state, false);
}
/**
* cpuhp_remove_state_nocalls_cpuslocked - Remove hotplug state callbacks without invoking
* teardown from a cpus_read_lock() held region.
* @state: The state for which the calls are removed
*
* Same as cpuhp_remove_state nocalls() except that it must be invoked
* from within a cpus_read_lock() held region.
*/
static inline void cpuhp_remove_state_nocalls_cpuslocked(enum cpuhp_state state)
{
__cpuhp_remove_state_cpuslocked(state, false);
}
/**
* cpuhp_remove_multi_state - Remove hotplug multi state callback
* @state: The state for which the calls are removed
*
* Removes the callback functions from a multi state. This is the reverse of
* cpuhp_setup_state_multi(). All instances should have been removed before
* invoking this function.
*/
static inline void cpuhp_remove_multi_state(enum cpuhp_state state)
{
__cpuhp_remove_state(state, false);
}
int __cpuhp_state_remove_instance(enum cpuhp_state state,
struct hlist_node *node, bool invoke);
/**
* cpuhp_state_remove_instance - Remove hotplug instance from state and invoke
* the teardown callback
* @state: The state from which the instance is removed
* @node: The node for this individual state.
*
* Removes the instance and invokes the teardown callback on the online cpus
* which have already reached @state.
*/
static inline int cpuhp_state_remove_instance(enum cpuhp_state state,
struct hlist_node *node)
{
return __cpuhp_state_remove_instance(state, node, true);
}
/**
* cpuhp_state_remove_instance_nocalls - Remove hotplug instance from state
* without invoking the teardown callback
* @state: The state from which the instance is removed
* @node: The node for this individual state.
*
* Removes the instance without invoking the teardown callback.
*/
static inline int cpuhp_state_remove_instance_nocalls(enum cpuhp_state state,
struct hlist_node *node)
{
return __cpuhp_state_remove_instance(state, node, false);
}
#ifdef CONFIG_SMP
void cpuhp_online_idle(enum cpuhp_state state);
#else
static inline void cpuhp_online_idle(enum cpuhp_state state) { }
#endif
struct task_struct;
void cpuhp_ap_sync_alive(void);
void arch_cpuhp_sync_state_poll(void);
void arch_cpuhp_cleanup_kick_cpu(unsigned int cpu);
int arch_cpuhp_kick_ap_alive(unsigned int cpu, struct task_struct *tidle);
bool arch_cpuhp_init_parallel_bringup(void);
#ifdef CONFIG_HOTPLUG_CORE_SYNC_DEAD
void cpuhp_ap_report_dead(void);
void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu);
#else
static inline void cpuhp_ap_report_dead(void) { }
static inline void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) { }
#endif
#endif
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