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 6B7FDC433EF for ; Sun, 1 May 2022 08:05:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239452AbiEAIJP (ORCPT ); Sun, 1 May 2022 04:09:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244147AbiEAII6 (ORCPT ); Sun, 1 May 2022 04:08:58 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 409601B7AD; Sun, 1 May 2022 01:05:30 -0700 (PDT) Date: Sun, 01 May 2022 08:05:28 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1651392329; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FMMsyxDebCqcfMfUt3x2z0M4LYkBUArkvhpibzV5ukg=; b=q39xNY4UoNiNb5L5kmlYYrjtrTDDUAtYn3yZw9csr1V2iXmUFXZqg/DnKwbZkVqqzVK1eR faqcqt+V4wG80BEK4H8UDPKBfHJ2BU5t/XlrjsVXijmV7btM78X3K7Meh7PP2OHjTa9sov KvYVWVGInBkbEhNHkxWUDFQmeCnZb+S5Ddds6mjmEbkjk0N/oCmSYahZdBuF18tEp95zRm lo9BoLMC/88uP+yxGRW9J3y0PpsKceglQNoeoEQQhD8ypGdhWzzdFLAZkhGNNDX98jJ+Xl SVWjL3CZMzlYQ+CwQevId1uTOXhMoL4g4RqnHg9HVT2z3AE1ZGUClf+D2KQ1Rw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1651392329; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FMMsyxDebCqcfMfUt3x2z0M4LYkBUArkvhpibzV5ukg=; b=C0CWj8nNW4zUsozU9GuKL2bMJAuQfAmLhQPQheoVX/LsG/5lg+H5zi7/S/z/EPaPZk+2/i danOB9iw/uV1SJCA== From: "tip-bot2 for Thomas Gleixner" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] smp: Rename flush_smp_call_function_from_idle() Cc: Thomas Gleixner , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20220413133024.305001096@linutronix.de> References: <20220413133024.305001096@linutronix.de> MIME-Version: 1.0 Message-ID: <165139232833.4207.2835999584883686606.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: 16bf5a5e1ec56474ed2a19d72f272ed09a5d3ea1 Gitweb: https://git.kernel.org/tip/16bf5a5e1ec56474ed2a19d72f272ed09a5d3ea1 Author: Thomas Gleixner AuthorDate: Wed, 13 Apr 2022 15:31:03 +02:00 Committer: Thomas Gleixner CommitterDate: Sun, 01 May 2022 10:03:43 +02:00 smp: Rename flush_smp_call_function_from_idle() 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 Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220413133024.305001096@linutronix.de --- 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(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e644578..07bacb0 100644 --- 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); diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 8f8b502..60295db 100644 --- 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))) diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h index 5719bf9..2eb23dd 100644 --- 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 diff --git a/kernel/smp.c b/kernel/smp.c index 01a7c17..8e85f22 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -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 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_interrupt(void) { 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_interrupt(void) * 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_queue(bool warn_cpu_offline) 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(void) 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();