From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36274C433EF for ; Wed, 13 Apr 2022 13:31:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235777AbiDMNdd (ORCPT ); Wed, 13 Apr 2022 09:33:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235765AbiDMNd0 (ORCPT ); Wed, 13 Apr 2022 09:33:26 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7DC72546A2 for ; Wed, 13 Apr 2022 06:31:05 -0700 (PDT) Message-ID: <20220413133024.305001096@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1649856664; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=g9e7k+CdFzSWcwYyvuM4WnmOYrbZsluI5FvW598pwQI=; b=WuHAhMpVp/wRdZax9ANdLw5blo5l1bKzyNuUatODEwUxlfVaVaOlzhFulApKQpjGezM4yR b8F300YrsiC/0rLlbhpKRDrfCVQ5AhOL5EMuGh2gpsbAEH74gWYCwWxB7RGxNUnvslRNaD bk35szds/l/htmdzgMsPvhAZAGoozoiXMqn5H9ns7+etGPfOPgnE8xedJ2tNPPaqd745h6 njYa57whj4QSTK32UNvWRel3e2gFwJtsNztp2y3Z0F+AIjXbJggPIDsunP4PFvvAju5cYV vt9tsvh9A7mTEemG1vsVDlO2GB0j8flbybIB7qbh0i0Srf4bd408gvx2eFYsrQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1649856664; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=g9e7k+CdFzSWcwYyvuM4WnmOYrbZsluI5FvW598pwQI=; b=/BbWiysCvtKDSCw+FKCVMF5LN//Jtjw0N6Qw1v+gzHTnziwTCPf2Q2GXW5oU/tWu1fM3qt rHqFUHVBmZ1bgcCQ== From: Thomas Gleixner To: LKML Cc: Christoph Hellwig , Peter Zijlstra , Sebastian Andrzej Siewior Subject: [patch V5 2/3] smp: Rename flush_smp_call_function_from_idle() References: <20220413132836.099363044@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Date: Wed, 13 Apr 2022 15:31:03 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- V4: New patch --- kernel/sched/core.c | 2 +- kernel/sched/idle.c | 2 +- kernel/sched/smp.h | 4 ++-- kernel/smp.c | 27 ++++++++++++++++++++------- 4 files changed, 24 insertions(+), 11 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2411,7 +2411,7 @@ static int migration_cpu_stop(void *data * __migrate_task() such that we will not miss enforcing cpus_ptr * 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); rq_lock(rq, &rf); --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -327,7 +327,7 @@ static void do_idle(void) * RCU relies on this call to be done outside of an RCU read-side * critical section. */ - flush_smp_call_function_from_idle(); + flush_smp_call_function_queue(); schedule_idle(); if (unlikely(klp_patch_pending(current))) --- a/kernel/sched/smp.h +++ b/kernel/sched/smp.h @@ -9,7 +9,7 @@ extern void sched_ttwu_pending(void *arg extern void send_call_function_single_ipi(int cpu); #ifdef CONFIG_SMP -extern void flush_smp_call_function_from_idle(void); +extern void flush_smp_call_function_queue(void); #else -static inline void flush_smp_call_function_from_idle(void) { } +static inline void flush_smp_call_function_queue(void) { } #endif --- a/kernel/smp.c +++ b/kernel/smp.c @@ -96,7 +96,7 @@ static DEFINE_PER_CPU_ALIGNED(struct cal 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) { @@ -141,7 +141,7 @@ int smpcfd_dying_cpu(unsigned int cpu) * ensure that the outgoing CPU doesn't go offline with work * still pending. */ - flush_smp_call_function_queue(false); + __flush_smp_call_function_queue(false); irq_work_run(); return 0; } @@ -541,11 +541,11 @@ void generic_smp_call_function_single_in { cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->gotipi, CFD_SEQ_NOCPU, 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 * offline CPU. Skip this check if set to 'false'. @@ -558,7 +558,7 @@ void generic_smp_call_function_single_in * Loop through the call_single_queue and run all the queued callbacks. * 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; struct llist_node *entry, *prev; @@ -681,7 +681,20 @@ static void flush_smp_call_function_queu 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; @@ -691,7 +704,7 @@ void flush_smp_call_function_from_idle(v cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->idle, CFD_SEQ_NOCPU, smp_processor_id(), CFD_SEQ_IDLE); local_irq_save(flags); - flush_smp_call_function_queue(true); + __flush_smp_call_function_queue(true); if (local_softirq_pending()) do_softirq();