flush_smp_c...nction_queue(9)

💅 flush_smp_c...nction_queue(9) 💅

okay bestie, welcome to the Kernel API Manual — this one's short but lowkey iconic, so buckle up 🎀

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✨ NAME ✨

flush_smp_call_function_queue — flush pending smp-call-function callbacks from task context (idle, migration thread) 🦋

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🌸 SYNOPSIS 🌸

void flush_smp_call_function_queue (void );

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💖 ARGUMENTS 💖

• void — no arguments, bestie. literally none. it takes nothing and it needs nothing 🫶

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👑 DESCRIPTION 👑

so here's the vibe. when TIF_POLLING_NRFLAG is supported and a CPU is in idle and has that flag set, then remote CPUs can skip sending IPIs entirely and instead just wake the idle CPU by setting TIF_NEED_RESCHED. slay, no IPI needed 💅

the idle task on that woken-up CPU, though? it has to handle the queued SMP function calls before it gets to scheduling. not optional. main character responsibility ✨

and the migration thread has to make sure that an eventually pending wakeup has been handled before it migrates a task. like, do the vibe check first, then migrate 🔥

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🌈 SEE ALSO 🌈

• Kernel file ./kernel/smp.c
• csd_lock_is_stuck(9)
• generic_smp_call_function_single_interrupt(9)
• __flush_smp_call_function_queue(9)
• smp_call_function_single(9)
• smp_call_function_single_async(9)
• smp_call_function_any(9)
• smp_call_function_many(9)
• smp_call_function(9)
• on_each_cpu_cond_mask(9)
• kick_all_cpus_sync(9)
• wake_up_all_idle_cpus(9)
• cpus_peek_for_pending_ipi(9)
• struct smp_call_on_cpu_struct(9)
• smp_call_on_cpu(9)

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okay that's the whole page, no cap 💀 it's a short one but she ate 💅

sign-off time, bestie: this iconic little doc lives under ./kernel, dated October 2026, and it's titled flush_smp_c...nction_queue(9) — go forth and flush those queues 🧚‍♀️⭐💜