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smp: Rename flush_smp_call_function_from_idle()

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This is invoked from the stopper thread too, which is definitely not idle.
Rename it to flush_smp_call_function_queue() and fixup the callers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220413133024.305001096@linutronix.de
This commit is contained in:
Thomas Gleixner 2022-04-13 15:31:03 +02:00
parent d664e39912
commit 16bf5a5e1e
4 changed files with 24 additions and 11 deletions
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2
kernel/sched/core.c
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@ -2411,7 +2411,7 @@ static int migration_cpu_stop(void *data)
* __migrate_task() such that we will not miss enforcing cpus_ptr * __migrate_task() such that we will not miss enforcing cpus_ptr
* during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test. * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
*/ */
flush_smp_call_function_from_idle(); flush_smp_call_function_queue();
raw_spin_lock(&p->pi_lock); raw_spin_lock(&p->pi_lock);
rq_lock(rq, &rf); rq_lock(rq, &rf);

2
kernel/sched/idle.c
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@ -327,7 +327,7 @@ static void do_idle(void)
* RCU relies on this call to be done outside of an RCU read-side * RCU relies on this call to be done outside of an RCU read-side
* critical section. * critical section.
*/ */
flush_smp_call_function_from_idle(); flush_smp_call_function_queue();
schedule_idle(); schedule_idle();
if (unlikely(klp_patch_pending(current))) if (unlikely(klp_patch_pending(current)))

4
kernel/sched/smp.h
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@ -9,7 +9,7 @@ extern void sched_ttwu_pending(void *arg);
extern void send_call_function_single_ipi(int cpu); extern void send_call_function_single_ipi(int cpu);
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
extern void flush_smp_call_function_from_idle(void); extern void flush_smp_call_function_queue(void);
#else #else
static inline void flush_smp_call_function_from_idle(void) { } static inline void flush_smp_call_function_queue(void) { }
#endif #endif

27
kernel/smp.c
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@ -96,7 +96,7 @@ static DEFINE_PER_CPU_ALIGNED(struct call_function_data, cfd_data);
static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue); static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue);
static void flush_smp_call_function_queue(bool warn_cpu_offline); static void __flush_smp_call_function_queue(bool warn_cpu_offline);
int smpcfd_prepare_cpu(unsigned int cpu) int smpcfd_prepare_cpu(unsigned int cpu)
{ {
@ -141,7 +141,7 @@ int smpcfd_dying_cpu(unsigned int cpu)
* ensure that the outgoing CPU doesn't go offline with work * ensure that the outgoing CPU doesn't go offline with work
* still pending. * still pending.
*/ */
flush_smp_call_function_queue(false); __flush_smp_call_function_queue(false);
irq_work_run(); irq_work_run();
return 0; return 0;
} }
@ -541,11 +541,11 @@ void generic_smp_call_function_single_interrupt(void)
{ {
cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->gotipi, CFD_SEQ_NOCPU, cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->gotipi, CFD_SEQ_NOCPU,
smp_processor_id(), CFD_SEQ_GOTIPI); smp_processor_id(), CFD_SEQ_GOTIPI);
flush_smp_call_function_queue(true); __flush_smp_call_function_queue(true);
} }
/** /**
* flush_smp_call_function_queue - Flush pending smp-call-function callbacks * __flush_smp_call_function_queue - Flush pending smp-call-function callbacks
* *
* @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an * @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an
* offline CPU. Skip this check if set to 'false'. * offline CPU. Skip this check if set to 'false'.
@ -558,7 +558,7 @@ void generic_smp_call_function_single_interrupt(void)
* Loop through the call_single_queue and run all the queued callbacks. * Loop through the call_single_queue and run all the queued callbacks.
* Must be called with interrupts disabled. * Must be called with interrupts disabled.
*/ */
static void flush_smp_call_function_queue(bool warn_cpu_offline) static void __flush_smp_call_function_queue(bool warn_cpu_offline)
{ {
call_single_data_t *csd, *csd_next; call_single_data_t *csd, *csd_next;
struct llist_node *entry, *prev; struct llist_node *entry, *prev;
@ -681,7 +681,20 @@ static void flush_smp_call_function_queue(bool warn_cpu_offline)
smp_processor_id(), CFD_SEQ_HDLEND); smp_processor_id(), CFD_SEQ_HDLEND);
} }
void flush_smp_call_function_from_idle(void)
/**
* flush_smp_call_function_queue - Flush pending smp-call-function callbacks
* from task context (idle, migration thread)
*
* When TIF_POLLING_NRFLAG is supported and a CPU is in idle and has it
* set, then remote CPUs can avoid sending IPIs and wake the idle CPU by
* setting TIF_NEED_RESCHED. The idle task on the woken up CPU has to
* handle queued SMP function calls before scheduling.
*
* The migration thread has to ensure that an eventually pending wakeup has
* been handled before it migrates a task.
*/
void flush_smp_call_function_queue(void)
{ {
unsigned long flags; unsigned long flags;
@ -691,7 +704,7 @@ void flush_smp_call_function_from_idle(void)
cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->idle, CFD_SEQ_NOCPU, cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->idle, CFD_SEQ_NOCPU,
smp_processor_id(), CFD_SEQ_IDLE); smp_processor_id(), CFD_SEQ_IDLE);
local_irq_save(flags); local_irq_save(flags);
flush_smp_call_function_queue(true); __flush_smp_call_function_queue(true);
if (local_softirq_pending()) if (local_softirq_pending())
do_softirq(); do_softirq();