From patchwork Fri May 26 20:52:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13257327 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 37C15C77B73 for ; Fri, 26 May 2023 21:01:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243937AbjEZVBe (ORCPT ); Fri, 26 May 2023 17:01:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243930AbjEZVBW (ORCPT ); Fri, 26 May 2023 17:01:22 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29EC71B3; Fri, 26 May 2023 14:01:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=G6EKcv9l36jxJ4ZUaeuw5XDMO86phqi+QGGvz1WsFmU=; b=YhAv1ZFJDw1KcRIrm9z+LE0Skn CY/UXuGrqIZcDCoKKFdEGp7wnKm/OEk0bSLtxpMixOvTXScIuIyB88iGCV4FqEZCZ+IuJkiYRdxXd 1RVI2x429sfYTdhud+4t/12GKQm8qbF4aVKQhHadiAHSaqvb/qp4Ioo6fFnUk9Uj0wjBuXH6LxjG+ Ofj/dj2bJRyteOIxXfH2pMMhYZovs9VJLzBW4KcRsgggv6dUBnZI3NB/oeyLDbJcKO2Qqf/5nU2Qz MGRCK2dZhgvc986QwjN5agtZ4dpMeHI3XYRF+IME73DSm4ZsZzspVeovK+JspIElYyGnwcDn8hOt8 Z0zoWszA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1q2eYG-007hpQ-2z; Fri, 26 May 2023 21:00:45 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 0A482300794; Fri, 26 May 2023 23:00:41 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id B9F8C205F1E05; Fri, 26 May 2023 23:00:41 +0200 (CEST) Message-ID: <20230526205855.656565626@infradead.org> User-Agent: quilt/0.66 Date: Fri, 26 May 2023 22:52:06 +0200 From: Peter Zijlstra To: torvalds@linux-foundation.org, keescook@chromium.org, gregkh@linuxfoundation.org, pbonzini@redhat.com Cc: linux-kernel@vger.kernel.org, ojeda@kernel.org, ndesaulniers@google.com, peterz@infradead.org, mingo@redhat.com, will@kernel.org, longman@redhat.com, boqun.feng@gmail.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, paulmck@kernel.org, frederic@kernel.org, quic_neeraju@quicinc.com, joel@joelfernandes.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, rcu@vger.kernel.org, tj@kernel.org, tglx@linutronix.de Subject: [PATCH v2 2/2] sched: Use fancy new guards References: <20230526205204.861311518@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org Convert kernel/sched/core.c to use the fancy new guards to simplify the error paths. Signed-off-by: Peter Zijlstra (Intel) --- kernel/sched/core.c | 1227 +++++++++++++++++++++++---------------------------- kernel/sched/sched.h | 34 + 2 files changed, 590 insertions(+), 671 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1097,24 +1097,21 @@ int get_nohz_timer_target(void) hk_mask = housekeeping_cpumask(HK_TYPE_TIMER); - rcu_read_lock(); - for_each_domain(cpu, sd) { - for_each_cpu_and(i, sched_domain_span(sd), hk_mask) { - if (cpu == i) - continue; + scoped (rcu) { + for_each_domain(cpu, sd) { + for_each_cpu_and(i, sched_domain_span(sd), hk_mask) { + if (cpu == i) + continue; - if (!idle_cpu(i)) { - cpu = i; - goto unlock; + if (!idle_cpu(i)) + return i; } } - } - if (default_cpu == -1) - default_cpu = housekeeping_any_cpu(HK_TYPE_TIMER); - cpu = default_cpu; -unlock: - rcu_read_unlock(); + if (default_cpu == -1) + default_cpu = housekeeping_any_cpu(HK_TYPE_TIMER); + cpu = default_cpu; + } return cpu; } @@ -1457,16 +1454,12 @@ static void __uclamp_update_util_min_rt_ static void uclamp_update_util_min_rt_default(struct task_struct *p) { - struct rq_flags rf; - struct rq *rq; - if (!rt_task(p)) return; /* Protect updates to p->uclamp_* */ - rq = task_rq_lock(p, &rf); - __uclamp_update_util_min_rt_default(p); - task_rq_unlock(rq, p, &rf); + scoped (task_rq_lock, p) + __uclamp_update_util_min_rt_default(p); } static inline struct uclamp_se @@ -1762,9 +1755,8 @@ static void uclamp_update_root_tg(void) uclamp_se_set(&tg->uclamp_req[UCLAMP_MAX], sysctl_sched_uclamp_util_max, false); - rcu_read_lock(); - cpu_util_update_eff(&root_task_group.css); - rcu_read_unlock(); + scoped (rcu) + cpu_util_update_eff(&root_task_group.css); } #else static void uclamp_update_root_tg(void) { } @@ -1791,10 +1783,10 @@ static void uclamp_sync_util_min_rt_defa smp_mb__after_spinlock(); read_unlock(&tasklist_lock); - rcu_read_lock(); - for_each_process_thread(g, p) - uclamp_update_util_min_rt_default(p); - rcu_read_unlock(); + scoped (rcu) { + for_each_process_thread(g, p) + uclamp_update_util_min_rt_default(p); + } } static int sysctl_sched_uclamp_handler(struct ctl_table *table, int write, @@ -1804,7 +1796,8 @@ static int sysctl_sched_uclamp_handler(s int old_min, old_max, old_min_rt; int result; - mutex_lock(&uclamp_mutex); + guard(mutex, guard, &uclamp_mutex); + old_min = sysctl_sched_uclamp_util_min; old_max = sysctl_sched_uclamp_util_max; old_min_rt = sysctl_sched_uclamp_util_min_rt_default; @@ -1813,7 +1806,7 @@ static int sysctl_sched_uclamp_handler(s if (result) goto undo; if (!write) - goto done; + return result; if (sysctl_sched_uclamp_util_min > sysctl_sched_uclamp_util_max || sysctl_sched_uclamp_util_max > SCHED_CAPACITY_SCALE || @@ -1849,16 +1842,12 @@ static int sysctl_sched_uclamp_handler(s * Otherwise, keep it simple and do just a lazy update at each next * task enqueue time. */ - - goto done; + return result; undo: sysctl_sched_uclamp_util_min = old_min; sysctl_sched_uclamp_util_max = old_max; sysctl_sched_uclamp_util_min_rt_default = old_min_rt; -done: - mutex_unlock(&uclamp_mutex); - return result; } #endif @@ -2249,10 +2238,10 @@ void migrate_disable(void) return; } - preempt_disable(); - this_rq()->nr_pinned++; - p->migration_disabled = 1; - preempt_enable(); + scoped (preempt) { + this_rq()->nr_pinned++; + p->migration_disabled = 1; + } } EXPORT_SYMBOL_GPL(migrate_disable); @@ -2276,18 +2265,18 @@ void migrate_enable(void) * Ensure stop_task runs either before or after this, and that * __set_cpus_allowed_ptr(SCA_MIGRATE_ENABLE) doesn't schedule(). */ - preempt_disable(); - if (p->cpus_ptr != &p->cpus_mask) - __set_cpus_allowed_ptr(p, &ac); - /* - * Mustn't clear migration_disabled() until cpus_ptr points back at the - * regular cpus_mask, otherwise things that race (eg. - * select_fallback_rq) get confused. - */ - barrier(); - p->migration_disabled = 0; - this_rq()->nr_pinned--; - preempt_enable(); + scoped (preempt) { + if (p->cpus_ptr != &p->cpus_mask) + __set_cpus_allowed_ptr(p, &ac); + /* + * Mustn't clear migration_disabled() until cpus_ptr points back at the + * regular cpus_mask, otherwise things that race (eg. + * select_fallback_rq) get confused. + */ + barrier(); + p->migration_disabled = 0; + this_rq()->nr_pinned--; + } } EXPORT_SYMBOL_GPL(migrate_enable); @@ -3272,31 +3261,26 @@ static int migrate_swap_stop(void *data) src_rq = cpu_rq(arg->src_cpu); dst_rq = cpu_rq(arg->dst_cpu); - double_raw_lock(&arg->src_task->pi_lock, - &arg->dst_task->pi_lock); - double_rq_lock(src_rq, dst_rq); - - if (task_cpu(arg->dst_task) != arg->dst_cpu) - goto unlock; + scoped (double_raw_spinlock, &arg->src_task->pi_lock, &arg->dst_task->pi_lock) { + guard(double_rq_lock, guard, src_rq, dst_rq); - if (task_cpu(arg->src_task) != arg->src_cpu) - goto unlock; + if (task_cpu(arg->dst_task) != arg->dst_cpu) + break; - if (!cpumask_test_cpu(arg->dst_cpu, arg->src_task->cpus_ptr)) - goto unlock; + if (task_cpu(arg->src_task) != arg->src_cpu) + break; - if (!cpumask_test_cpu(arg->src_cpu, arg->dst_task->cpus_ptr)) - goto unlock; + if (!cpumask_test_cpu(arg->dst_cpu, arg->src_task->cpus_ptr)) + break; - __migrate_swap_task(arg->src_task, arg->dst_cpu); - __migrate_swap_task(arg->dst_task, arg->src_cpu); + if (!cpumask_test_cpu(arg->src_cpu, arg->dst_task->cpus_ptr)) + break; - ret = 0; + __migrate_swap_task(arg->src_task, arg->dst_cpu); + __migrate_swap_task(arg->dst_task, arg->src_cpu); -unlock: - double_rq_unlock(src_rq, dst_rq); - raw_spin_unlock(&arg->dst_task->pi_lock); - raw_spin_unlock(&arg->src_task->pi_lock); + ret = 0; + } return ret; } @@ -3464,13 +3448,11 @@ unsigned long wait_task_inactive(struct */ void kick_process(struct task_struct *p) { - int cpu; + guard(preempt, guard); + int cpu = task_cpu(p); - preempt_disable(); - cpu = task_cpu(p); if ((cpu != smp_processor_id()) && task_curr(p)) smp_send_reschedule(cpu); - preempt_enable(); } EXPORT_SYMBOL_GPL(kick_process); @@ -3679,16 +3661,15 @@ ttwu_stat(struct task_struct *p, int cpu __schedstat_inc(p->stats.nr_wakeups_local); } else { struct sched_domain *sd; + guard(rcu, guard); __schedstat_inc(p->stats.nr_wakeups_remote); - rcu_read_lock(); for_each_domain(rq->cpu, sd) { if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { __schedstat_inc(sd->ttwu_wake_remote); break; } } - rcu_read_unlock(); } if (wake_flags & WF_MIGRATED) @@ -3887,21 +3868,13 @@ static void __ttwu_queue_wakelist(struct void wake_up_if_idle(int cpu) { struct rq *rq = cpu_rq(cpu); - struct rq_flags rf; - - rcu_read_lock(); - - if (!is_idle_task(rcu_dereference(rq->curr))) - goto out; - rq_lock_irqsave(rq, &rf); - if (is_idle_task(rq->curr)) - resched_curr(rq); - /* Else CPU is not idle, do nothing here: */ - rq_unlock_irqrestore(rq, &rf); - -out: - rcu_read_unlock(); + guard(rcu, guard); + if (is_idle_task(rcu_dereference(rq->curr))) { + guard(rq_lock, rq_guard, rq); + if (is_idle_task(rq->curr)) + resched_curr(rq); + } } bool cpus_share_cache(int this_cpu, int that_cpu) @@ -4158,10 +4131,9 @@ bool ttwu_state_match(struct task_struct static int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) { - unsigned long flags; + guard(preempt, guard); int cpu, success = 0; - preempt_disable(); if (p == current) { /* * We're waking current, this means 'p->on_rq' and 'task_cpu(p) @@ -4188,129 +4160,127 @@ try_to_wake_up(struct task_struct *p, un * reordered with p->state check below. This pairs with smp_store_mb() * in set_current_state() that the waiting thread does. */ - raw_spin_lock_irqsave(&p->pi_lock, flags); - smp_mb__after_spinlock(); - if (!ttwu_state_match(p, state, &success)) - goto unlock; + scoped (raw_spinlock_irqsave, &p->pi_lock) { + smp_mb__after_spinlock(); + if (!ttwu_state_match(p, state, &success)) + break; - trace_sched_waking(p); + trace_sched_waking(p); - /* - * Ensure we load p->on_rq _after_ p->state, otherwise it would - * be possible to, falsely, observe p->on_rq == 0 and get stuck - * in smp_cond_load_acquire() below. - * - * sched_ttwu_pending() try_to_wake_up() - * STORE p->on_rq = 1 LOAD p->state - * UNLOCK rq->lock - * - * __schedule() (switch to task 'p') - * LOCK rq->lock smp_rmb(); - * smp_mb__after_spinlock(); - * UNLOCK rq->lock - * - * [task p] - * STORE p->state = UNINTERRUPTIBLE LOAD p->on_rq - * - * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in - * __schedule(). See the comment for smp_mb__after_spinlock(). - * - * A similar smb_rmb() lives in try_invoke_on_locked_down_task(). - */ - smp_rmb(); - if (READ_ONCE(p->on_rq) && ttwu_runnable(p, wake_flags)) - goto unlock; + /* + * Ensure we load p->on_rq _after_ p->state, otherwise it would + * be possible to, falsely, observe p->on_rq == 0 and get stuck + * in smp_cond_load_acquire() below. + * + * sched_ttwu_pending() try_to_wake_up() + * STORE p->on_rq = 1 LOAD p->state + * UNLOCK rq->lock + * + * __schedule() (switch to task 'p') + * LOCK rq->lock smp_rmb(); + * smp_mb__after_spinlock(); + * UNLOCK rq->lock + * + * [task p] + * STORE p->state = UNINTERRUPTIBLE LOAD p->on_rq + * + * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in + * __schedule(). See the comment for smp_mb__after_spinlock(). + * + * A similar smb_rmb() lives in try_invoke_on_locked_down_task(). + */ + smp_rmb(); + if (READ_ONCE(p->on_rq) && ttwu_runnable(p, wake_flags)) + break; #ifdef CONFIG_SMP - /* - * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be - * possible to, falsely, observe p->on_cpu == 0. - * - * One must be running (->on_cpu == 1) in order to remove oneself - * from the runqueue. - * - * __schedule() (switch to task 'p') try_to_wake_up() - * STORE p->on_cpu = 1 LOAD p->on_rq - * UNLOCK rq->lock - * - * __schedule() (put 'p' to sleep) - * LOCK rq->lock smp_rmb(); - * smp_mb__after_spinlock(); - * STORE p->on_rq = 0 LOAD p->on_cpu - * - * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in - * __schedule(). See the comment for smp_mb__after_spinlock(). - * - * Form a control-dep-acquire with p->on_rq == 0 above, to ensure - * schedule()'s deactivate_task() has 'happened' and p will no longer - * care about it's own p->state. See the comment in __schedule(). - */ - smp_acquire__after_ctrl_dep(); + /* + * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be + * possible to, falsely, observe p->on_cpu == 0. + * + * One must be running (->on_cpu == 1) in order to remove oneself + * from the runqueue. + * + * __schedule() (switch to task 'p') try_to_wake_up() + * STORE p->on_cpu = 1 LOAD p->on_rq + * UNLOCK rq->lock + * + * __schedule() (put 'p' to sleep) + * LOCK rq->lock smp_rmb(); + * smp_mb__after_spinlock(); + * STORE p->on_rq = 0 LOAD p->on_cpu + * + * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in + * __schedule(). See the comment for smp_mb__after_spinlock(). + * + * Form a control-dep-acquire with p->on_rq == 0 above, to ensure + * schedule()'s deactivate_task() has 'happened' and p will no longer + * care about it's own p->state. See the comment in __schedule(). + */ + smp_acquire__after_ctrl_dep(); - /* - * We're doing the wakeup (@success == 1), they did a dequeue (p->on_rq - * == 0), which means we need to do an enqueue, change p->state to - * TASK_WAKING such that we can unlock p->pi_lock before doing the - * enqueue, such as ttwu_queue_wakelist(). - */ - WRITE_ONCE(p->__state, TASK_WAKING); + /* + * We're doing the wakeup (@success == 1), they did a dequeue (p->on_rq + * == 0), which means we need to do an enqueue, change p->state to + * TASK_WAKING such that we can unlock p->pi_lock before doing the + * enqueue, such as ttwu_queue_wakelist(). + */ + WRITE_ONCE(p->__state, TASK_WAKING); - /* - * If the owning (remote) CPU is still in the middle of schedule() with - * this task as prev, considering queueing p on the remote CPUs wake_list - * which potentially sends an IPI instead of spinning on p->on_cpu to - * let the waker make forward progress. This is safe because IRQs are - * disabled and the IPI will deliver after on_cpu is cleared. - * - * Ensure we load task_cpu(p) after p->on_cpu: - * - * set_task_cpu(p, cpu); - * STORE p->cpu = @cpu - * __schedule() (switch to task 'p') - * LOCK rq->lock - * smp_mb__after_spin_lock() smp_cond_load_acquire(&p->on_cpu) - * STORE p->on_cpu = 1 LOAD p->cpu - * - * to ensure we observe the correct CPU on which the task is currently - * scheduling. - */ - if (smp_load_acquire(&p->on_cpu) && - ttwu_queue_wakelist(p, task_cpu(p), wake_flags)) - goto unlock; + /* + * If the owning (remote) CPU is still in the middle of schedule() with + * this task as prev, considering queueing p on the remote CPUs wake_list + * which potentially sends an IPI instead of spinning on p->on_cpu to + * let the waker make forward progress. This is safe because IRQs are + * disabled and the IPI will deliver after on_cpu is cleared. + * + * Ensure we load task_cpu(p) after p->on_cpu: + * + * set_task_cpu(p, cpu); + * STORE p->cpu = @cpu + * __schedule() (switch to task 'p') + * LOCK rq->lock + * smp_mb__after_spin_lock() smp_cond_load_acquire(&p->on_cpu) + * STORE p->on_cpu = 1 LOAD p->cpu + * + * to ensure we observe the correct CPU on which the task is currently + * scheduling. + */ + if (smp_load_acquire(&p->on_cpu) && + ttwu_queue_wakelist(p, task_cpu(p), wake_flags)) + break; - /* - * If the owning (remote) CPU is still in the middle of schedule() with - * this task as prev, wait until it's done referencing the task. - * - * Pairs with the smp_store_release() in finish_task(). - * - * This ensures that tasks getting woken will be fully ordered against - * their previous state and preserve Program Order. - */ - smp_cond_load_acquire(&p->on_cpu, !VAL); + /* + * If the owning (remote) CPU is still in the middle of schedule() with + * this task as prev, wait until it's done referencing the task. + * + * Pairs with the smp_store_release() in finish_task(). + * + * This ensures that tasks getting woken will be fully ordered against + * their previous state and preserve Program Order. + */ + smp_cond_load_acquire(&p->on_cpu, !VAL); - cpu = select_task_rq(p, p->wake_cpu, wake_flags | WF_TTWU); - if (task_cpu(p) != cpu) { - if (p->in_iowait) { - delayacct_blkio_end(p); - atomic_dec(&task_rq(p)->nr_iowait); - } + cpu = select_task_rq(p, p->wake_cpu, wake_flags | WF_TTWU); + if (task_cpu(p) != cpu) { + if (p->in_iowait) { + delayacct_blkio_end(p); + atomic_dec(&task_rq(p)->nr_iowait); + } - wake_flags |= WF_MIGRATED; - psi_ttwu_dequeue(p); - set_task_cpu(p, cpu); - } + wake_flags |= WF_MIGRATED; + psi_ttwu_dequeue(p); + set_task_cpu(p, cpu); + } #else - cpu = task_cpu(p); + cpu = task_cpu(p); #endif /* CONFIG_SMP */ - ttwu_queue(p, cpu, wake_flags); -unlock: - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + ttwu_queue(p, cpu, wake_flags); + } out: if (success) ttwu_stat(p, task_cpu(p), wake_flags); - preempt_enable(); return success; } @@ -5458,23 +5428,20 @@ unsigned int nr_iowait(void) void sched_exec(void) { struct task_struct *p = current; - unsigned long flags; + struct migration_arg arg; int dest_cpu; - raw_spin_lock_irqsave(&p->pi_lock, flags); - dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), WF_EXEC); - if (dest_cpu == smp_processor_id()) - goto unlock; + scoped (raw_spinlock_irqsave, &p->pi_lock) { + dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), WF_EXEC); + if (dest_cpu == smp_processor_id()) + return; - if (likely(cpu_active(dest_cpu))) { - struct migration_arg arg = { p, dest_cpu }; + if (unlikely(!cpu_active(dest_cpu))) + return; - raw_spin_unlock_irqrestore(&p->pi_lock, flags); - stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); - return; + arg = (struct migration_arg){ p, dest_cpu }; } -unlock: - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); } #endif @@ -5681,9 +5648,6 @@ static void sched_tick_remote(struct wor struct tick_work *twork = container_of(dwork, struct tick_work, work); int cpu = twork->cpu; struct rq *rq = cpu_rq(cpu); - struct task_struct *curr; - struct rq_flags rf; - u64 delta; int os; /* @@ -5693,30 +5657,28 @@ static void sched_tick_remote(struct wor * statistics and checks timeslices in a time-independent way, regardless * of when exactly it is running. */ - if (!tick_nohz_tick_stopped_cpu(cpu)) - goto out_requeue; + if (tick_nohz_tick_stopped_cpu(cpu)) { + scoped (rq_lock_irq, rq) { + struct task_struct *curr = rq->curr; - rq_lock_irq(rq, &rf); - curr = rq->curr; - if (cpu_is_offline(cpu)) - goto out_unlock; + if (cpu_is_offline(cpu)) + break; - update_rq_clock(rq); + update_rq_clock(rq); - if (!is_idle_task(curr)) { - /* - * Make sure the next tick runs within a reasonable - * amount of time. - */ - delta = rq_clock_task(rq) - curr->se.exec_start; - WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3); - } - curr->sched_class->task_tick(rq, curr, 0); + if (!is_idle_task(curr)) { + /* + * Make sure the next tick runs within a + * reasonable amount of time. + */ + u64 delta = rq_clock_task(rq) - curr->se.exec_start; + WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3); + } + curr->sched_class->task_tick(rq, curr, 0); - calc_load_nohz_remote(rq); -out_unlock: - rq_unlock_irq(rq, &rf); -out_requeue: + calc_load_nohz_remote(rq); + } + } /* * Run the remote tick once per second (1Hz). This arbitrary @@ -6265,53 +6227,51 @@ static bool try_steal_cookie(int this, i unsigned long cookie; bool success = false; - local_irq_disable(); - double_rq_lock(dst, src); + scoped (irq) { + guard(double_rq_lock, guard, dst, src); - cookie = dst->core->core_cookie; - if (!cookie) - goto unlock; + cookie = dst->core->core_cookie; + if (!cookie) + break; - if (dst->curr != dst->idle) - goto unlock; + if (dst->curr != dst->idle) + break; - p = sched_core_find(src, cookie); - if (!p) - goto unlock; + p = sched_core_find(src, cookie); + if (!p) + break; - do { - if (p == src->core_pick || p == src->curr) - goto next; + do { + if (p == src->core_pick || p == src->curr) + goto next; - if (!is_cpu_allowed(p, this)) - goto next; + if (!is_cpu_allowed(p, this)) + goto next; - if (p->core_occupation > dst->idle->core_occupation) - goto next; - /* - * sched_core_find() and sched_core_next() will ensure that task @p - * is not throttled now, we also need to check whether the runqueue - * of the destination CPU is being throttled. - */ - if (sched_task_is_throttled(p, this)) - goto next; + if (p->core_occupation > dst->idle->core_occupation) + goto next; + /* + * sched_core_find() and sched_core_next() will ensure + * that task @p is not throttled now, we also need to + * check whether the runqueue of the destination CPU is + * being throttled. + */ + if (sched_task_is_throttled(p, this)) + goto next; - deactivate_task(src, p, 0); - set_task_cpu(p, this); - activate_task(dst, p, 0); + deactivate_task(src, p, 0); + set_task_cpu(p, this); + activate_task(dst, p, 0); - resched_curr(dst); + resched_curr(dst); - success = true; - break; + success = true; + break; next: - p = sched_core_next(p, cookie); - } while (p); - -unlock: - double_rq_unlock(dst, src); - local_irq_enable(); + p = sched_core_next(p, cookie); + } while (p); + } return success; } @@ -6339,8 +6299,9 @@ static void sched_core_balance(struct rq struct sched_domain *sd; int cpu = cpu_of(rq); - preempt_disable(); - rcu_read_lock(); + guard(preempt, pg); + guard(rcu, rg); + raw_spin_rq_unlock_irq(rq); for_each_domain(cpu, sd) { if (need_resched()) @@ -6350,8 +6311,6 @@ static void sched_core_balance(struct rq break; } raw_spin_rq_lock_irq(rq); - rcu_read_unlock(); - preempt_enable(); } static DEFINE_PER_CPU(struct balance_callback, core_balance_head); @@ -6370,20 +6329,24 @@ static void queue_core_balance(struct rq queue_balance_callback(rq, &per_cpu(core_balance_head, rq->cpu), sched_core_balance); } +DEFINE_LOCK_GUARD_1(core_lock, int, + sched_core_lock(*_G->lock, &_G->flags), + sched_core_unlock(*_G->lock, &_G->flags), + unsigned long flags) + static void sched_core_cpu_starting(unsigned int cpu) { const struct cpumask *smt_mask = cpu_smt_mask(cpu); struct rq *rq = cpu_rq(cpu), *core_rq = NULL; - unsigned long flags; int t; - sched_core_lock(cpu, &flags); + guard(core_lock, guard, &cpu); WARN_ON_ONCE(rq->core != rq); /* if we're the first, we'll be our own leader */ if (cpumask_weight(smt_mask) == 1) - goto unlock; + return; /* find the leader */ for_each_cpu(t, smt_mask) { @@ -6397,7 +6360,7 @@ static void sched_core_cpu_starting(unsi } if (WARN_ON_ONCE(!core_rq)) /* whoopsie */ - goto unlock; + return; /* install and validate core_rq */ for_each_cpu(t, smt_mask) { @@ -6408,29 +6371,25 @@ static void sched_core_cpu_starting(unsi WARN_ON_ONCE(rq->core != core_rq); } - -unlock: - sched_core_unlock(cpu, &flags); } static void sched_core_cpu_deactivate(unsigned int cpu) { const struct cpumask *smt_mask = cpu_smt_mask(cpu); struct rq *rq = cpu_rq(cpu), *core_rq = NULL; - unsigned long flags; int t; - sched_core_lock(cpu, &flags); + guard(core_lock, guard, &cpu); /* if we're the last man standing, nothing to do */ if (cpumask_weight(smt_mask) == 1) { WARN_ON_ONCE(rq->core != rq); - goto unlock; + return; } /* if we're not the leader, nothing to do */ if (rq->core != rq) - goto unlock; + return; /* find a new leader */ for_each_cpu(t, smt_mask) { @@ -6441,7 +6400,7 @@ static void sched_core_cpu_deactivate(un } if (WARN_ON_ONCE(!core_rq)) /* impossible */ - goto unlock; + return; /* copy the shared state to the new leader */ core_rq->core_task_seq = rq->core_task_seq; @@ -6463,9 +6422,6 @@ static void sched_core_cpu_deactivate(un rq = cpu_rq(t); rq->core = core_rq; } - -unlock: - sched_core_unlock(cpu, &flags); } static inline void sched_core_cpu_dying(unsigned int cpu) @@ -7162,8 +7118,6 @@ void set_user_nice(struct task_struct *p { bool queued, running; int old_prio; - struct rq_flags rf; - struct rq *rq; if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) return; @@ -7171,44 +7125,45 @@ void set_user_nice(struct task_struct *p * We have to be careful, if called from sys_setpriority(), * the task might be in the middle of scheduling on another CPU. */ - rq = task_rq_lock(p, &rf); - update_rq_clock(rq); + scoped (task_rq_lock, p) { + struct rq *rq = _scope.rq; - /* - * The RT priorities are set via sched_setscheduler(), but we still - * allow the 'normal' nice value to be set - but as expected - * it won't have any effect on scheduling until the task is - * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: - */ - if (task_has_dl_policy(p) || task_has_rt_policy(p)) { - p->static_prio = NICE_TO_PRIO(nice); - goto out_unlock; - } - queued = task_on_rq_queued(p); - running = task_current(rq, p); - if (queued) - dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK); - if (running) - put_prev_task(rq, p); + update_rq_clock(rq); - p->static_prio = NICE_TO_PRIO(nice); - set_load_weight(p, true); - old_prio = p->prio; - p->prio = effective_prio(p); + /* + * The RT priorities are set via sched_setscheduler(), but we still + * allow the 'normal' nice value to be set - but as expected + * it won't have any effect on scheduling until the task is + * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: + */ + if (task_has_dl_policy(p) || task_has_rt_policy(p)) { + p->static_prio = NICE_TO_PRIO(nice); + return; + } - if (queued) - enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK); - if (running) - set_next_task(rq, p); + queued = task_on_rq_queued(p); + running = task_current(rq, p); + if (queued) + dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK); + if (running) + put_prev_task(rq, p); - /* - * If the task increased its priority or is running and - * lowered its priority, then reschedule its CPU: - */ - p->sched_class->prio_changed(rq, p, old_prio); + p->static_prio = NICE_TO_PRIO(nice); + set_load_weight(p, true); + old_prio = p->prio; + p->prio = effective_prio(p); -out_unlock: - task_rq_unlock(rq, p, &rf); + if (queued) + enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK); + if (running) + set_next_task(rq, p); + + /* + * If the task increased its priority or is running and + * lowered its priority, then reschedule its CPU: + */ + p->sched_class->prio_changed(rq, p, old_prio); + } } EXPORT_SYMBOL(set_user_nice); @@ -7468,6 +7423,19 @@ static struct task_struct *find_process_ return pid ? find_task_by_vpid(pid) : current; } +static struct task_struct *find_get_task(pid_t pid) +{ + struct task_struct *p; + + scoped (rcu) { + p = find_process_by_pid(pid); + if (likely(p)) + get_task_struct(p); + } + + return p; +} + /* * sched_setparam() passes in -1 for its policy, to let the functions * it calls know not to change it. @@ -7505,14 +7473,11 @@ static void __setscheduler_params(struct static bool check_same_owner(struct task_struct *p) { const struct cred *cred = current_cred(), *pcred; - bool match; + guard(rcu, guard); - rcu_read_lock(); pcred = __task_cred(p); - match = (uid_eq(cred->euid, pcred->euid) || - uid_eq(cred->euid, pcred->uid)); - rcu_read_unlock(); - return match; + return (uid_eq(cred->euid, pcred->euid) || + uid_eq(cred->euid, pcred->uid)); } /* @@ -7915,28 +7880,19 @@ EXPORT_SYMBOL_GPL(sched_set_normal); static int do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) { + ptr_guard(put_task, p) = NULL; struct sched_param lparam; - struct task_struct *p; - int retval; if (!param || pid < 0) return -EINVAL; if (copy_from_user(&lparam, param, sizeof(struct sched_param))) return -EFAULT; - rcu_read_lock(); - retval = -ESRCH; - p = find_process_by_pid(pid); - if (likely(p)) - get_task_struct(p); - rcu_read_unlock(); - - if (likely(p)) { - retval = sched_setscheduler(p, policy, &lparam); - put_task_struct(p); - } + p = find_get_task(pid); + if (!p) + return -ESRCH; - return retval; + return sched_setscheduler(p, policy, &lparam); } /* @@ -8031,8 +7987,8 @@ SYSCALL_DEFINE2(sched_setparam, pid_t, p SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, unsigned int, flags) { + ptr_guard(put_task, p) = NULL; struct sched_attr attr; - struct task_struct *p; int retval; if (!uattr || pid < 0 || flags) @@ -8047,21 +8003,14 @@ SYSCALL_DEFINE3(sched_setattr, pid_t, pi if (attr.sched_flags & SCHED_FLAG_KEEP_POLICY) attr.sched_policy = SETPARAM_POLICY; - rcu_read_lock(); - retval = -ESRCH; - p = find_process_by_pid(pid); - if (likely(p)) - get_task_struct(p); - rcu_read_unlock(); + p = find_get_task(pid); + if (!p) + return -ESRCH; - if (likely(p)) { - if (attr.sched_flags & SCHED_FLAG_KEEP_PARAMS) - get_params(p, &attr); - retval = sched_setattr(p, &attr); - put_task_struct(p); - } + if (attr.sched_flags & SCHED_FLAG_KEEP_PARAMS) + get_params(p, &attr); - return retval; + return sched_setattr(p, &attr); } /** @@ -8079,16 +8028,19 @@ SYSCALL_DEFINE1(sched_getscheduler, pid_ if (pid < 0) return -EINVAL; - retval = -ESRCH; - rcu_read_lock(); - p = find_process_by_pid(pid); - if (p) { + scoped (rcu) { + p = find_process_by_pid(pid); + if (!p) + return -ESRCH; + retval = security_task_getscheduler(p); - if (!retval) - retval = p->policy - | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); + if (!retval) { + retval = p->policy; + if (p->sched_reset_on_fork) + retval |= SCHED_RESET_ON_FORK; + } } - rcu_read_unlock(); + return retval; } @@ -8109,30 +8061,23 @@ SYSCALL_DEFINE2(sched_getparam, pid_t, p if (!param || pid < 0) return -EINVAL; - rcu_read_lock(); - p = find_process_by_pid(pid); - retval = -ESRCH; - if (!p) - goto out_unlock; + scoped (rcu) { + p = find_process_by_pid(pid); + if (!p) + return -ESRCH; - retval = security_task_getscheduler(p); - if (retval) - goto out_unlock; + retval = security_task_getscheduler(p); + if (retval) + return retval; - if (task_has_rt_policy(p)) - lp.sched_priority = p->rt_priority; - rcu_read_unlock(); + if (task_has_rt_policy(p)) + lp.sched_priority = p->rt_priority; + } /* * This one might sleep, we cannot do it with a spinlock held ... */ - retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; - - return retval; - -out_unlock: - rcu_read_unlock(); - return retval; + return copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; } /* @@ -8192,39 +8137,33 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pi usize < SCHED_ATTR_SIZE_VER0 || flags) return -EINVAL; - rcu_read_lock(); - p = find_process_by_pid(pid); - retval = -ESRCH; - if (!p) - goto out_unlock; + scoped (rcu) { + p = find_process_by_pid(pid); + if (!p) + return -ESRCH; - retval = security_task_getscheduler(p); - if (retval) - goto out_unlock; + retval = security_task_getscheduler(p); + if (retval) + return retval; - kattr.sched_policy = p->policy; - if (p->sched_reset_on_fork) - kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; - get_params(p, &kattr); - kattr.sched_flags &= SCHED_FLAG_ALL; + kattr.sched_policy = p->policy; + if (p->sched_reset_on_fork) + kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; + get_params(p, &kattr); + kattr.sched_flags &= SCHED_FLAG_ALL; #ifdef CONFIG_UCLAMP_TASK - /* - * This could race with another potential updater, but this is fine - * because it'll correctly read the old or the new value. We don't need - * to guarantee who wins the race as long as it doesn't return garbage. - */ - kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value; - kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value; + /* + * This could race with another potential updater, but this is fine + * because it'll correctly read the old or the new value. We don't need + * to guarantee who wins the race as long as it doesn't return garbage. + */ + kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value; + kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value; #endif - - rcu_read_unlock(); + } return sched_attr_copy_to_user(uattr, &kattr, usize); - -out_unlock: - rcu_read_unlock(); - return retval; } #ifdef CONFIG_SMP @@ -8245,10 +8184,10 @@ int dl_task_check_affinity(struct task_s * tasks allowed to run on all the CPUs in the task's * root_domain. */ - rcu_read_lock(); - if (!cpumask_subset(task_rq(p)->rd->span, mask)) - ret = -EBUSY; - rcu_read_unlock(); + scoped (rcu) { + if (!cpumask_subset(task_rq(p)->rd->span, mask)) + ret = -EBUSY; + } return ret; } #endif @@ -8317,41 +8256,27 @@ __sched_setaffinity(struct task_struct * long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) { + ptr_guard(put_task, p) = NULL; struct affinity_context ac; struct cpumask *user_mask; - struct task_struct *p; int retval; - rcu_read_lock(); - - p = find_process_by_pid(pid); - if (!p) { - rcu_read_unlock(); + p = find_get_task(pid); + if (!p) return -ESRCH; - } - - /* Prevent p going away */ - get_task_struct(p); - rcu_read_unlock(); - if (p->flags & PF_NO_SETAFFINITY) { - retval = -EINVAL; - goto out_put_task; - } + if (p->flags & PF_NO_SETAFFINITY) + return -EINVAL; if (!check_same_owner(p)) { - rcu_read_lock(); - if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { - rcu_read_unlock(); - retval = -EPERM; - goto out_put_task; - } - rcu_read_unlock(); + guard(rcu, rg); + if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) + return -EPERM; } retval = security_task_setscheduler(p); if (retval) - goto out_put_task; + return retval; /* * With non-SMP configs, user_cpus_ptr/user_mask isn't used and @@ -8361,8 +8286,7 @@ long sched_setaffinity(pid_t pid, const if (user_mask) { cpumask_copy(user_mask, in_mask); } else if (IS_ENABLED(CONFIG_SMP)) { - retval = -ENOMEM; - goto out_put_task; + return -ENOMEM; } ac = (struct affinity_context){ @@ -8374,8 +8298,6 @@ long sched_setaffinity(pid_t pid, const retval = __sched_setaffinity(p, &ac); kfree(ac.user_mask); -out_put_task: - put_task_struct(p); return retval; } @@ -8417,28 +8339,22 @@ SYSCALL_DEFINE3(sched_setaffinity, pid_t long sched_getaffinity(pid_t pid, struct cpumask *mask) { struct task_struct *p; - unsigned long flags; int retval; - rcu_read_lock(); + scoped (rcu) { + p = find_process_by_pid(pid); + if (!p) + return -ESRCH; - retval = -ESRCH; - p = find_process_by_pid(pid); - if (!p) - goto out_unlock; - - retval = security_task_getscheduler(p); - if (retval) - goto out_unlock; - - raw_spin_lock_irqsave(&p->pi_lock, flags); - cpumask_and(mask, &p->cpus_mask, cpu_active_mask); - raw_spin_unlock_irqrestore(&p->pi_lock, flags); + retval = security_task_getscheduler(p); + if (retval) + return retval; -out_unlock: - rcu_read_unlock(); + scoped (raw_spinlock_irqsave, &p->pi_lock) + cpumask_and(mask, &p->cpus_mask, cpu_active_mask); + } - return retval; + return 0; } /** @@ -8885,55 +8801,47 @@ int __sched yield_to(struct task_struct { struct task_struct *curr = current; struct rq *rq, *p_rq; - unsigned long flags; int yielded = 0; - local_irq_save(flags); - rq = this_rq(); + scoped (irqsave) { + rq = this_rq(); again: - p_rq = task_rq(p); - /* - * If we're the only runnable task on the rq and target rq also - * has only one task, there's absolutely no point in yielding. - */ - if (rq->nr_running == 1 && p_rq->nr_running == 1) { - yielded = -ESRCH; - goto out_irq; - } + p_rq = task_rq(p); + /* + * If we're the only runnable task on the rq and target rq also + * has only one task, there's absolutely no point in yielding. + */ + if (rq->nr_running == 1 && p_rq->nr_running == 1) + return -ESRCH; - double_rq_lock(rq, p_rq); - if (task_rq(p) != p_rq) { - double_rq_unlock(rq, p_rq); - goto again; - } + scoped (double_rq_lock, rq, p_rq) { + if (task_rq(p) != p_rq) + goto again; - if (!curr->sched_class->yield_to_task) - goto out_unlock; + if (!curr->sched_class->yield_to_task) + return 0; - if (curr->sched_class != p->sched_class) - goto out_unlock; + if (curr->sched_class != p->sched_class) + return 0; - if (task_on_cpu(p_rq, p) || !task_is_running(p)) - goto out_unlock; + if (task_on_cpu(p_rq, p) || !task_is_running(p)) + return 0; - yielded = curr->sched_class->yield_to_task(rq, p); - if (yielded) { - schedstat_inc(rq->yld_count); - /* - * Make p's CPU reschedule; pick_next_entity takes care of - * fairness. - */ - if (preempt && rq != p_rq) - resched_curr(p_rq); + yielded = curr->sched_class->yield_to_task(rq, p); + if (yielded) { + schedstat_inc(rq->yld_count); + /* + * Make p's CPU reschedule; pick_next_entity + * takes care of fairness. + */ + if (preempt && rq != p_rq) + resched_curr(p_rq); + } + } } -out_unlock: - double_rq_unlock(rq, p_rq); -out_irq: - local_irq_restore(flags); - - if (yielded > 0) + if (yielded) schedule(); return yielded; @@ -9036,38 +8944,30 @@ SYSCALL_DEFINE1(sched_get_priority_min, static int sched_rr_get_interval(pid_t pid, struct timespec64 *t) { - struct task_struct *p; - unsigned int time_slice; - struct rq_flags rf; - struct rq *rq; + unsigned int time_slice = 0; int retval; if (pid < 0) return -EINVAL; - retval = -ESRCH; - rcu_read_lock(); - p = find_process_by_pid(pid); - if (!p) - goto out_unlock; + scoped (rcu) { + struct task_struct *p = find_process_by_pid(pid); + if (!p) + return -ESRCH; - retval = security_task_getscheduler(p); - if (retval) - goto out_unlock; + retval = security_task_getscheduler(p); + if (retval) + return retval; - rq = task_rq_lock(p, &rf); - time_slice = 0; - if (p->sched_class->get_rr_interval) - time_slice = p->sched_class->get_rr_interval(rq, p); - task_rq_unlock(rq, p, &rf); + scoped (task_rq_lock, p) { + struct rq *rq = _scope.rq; + if (p->sched_class->get_rr_interval) + time_slice = p->sched_class->get_rr_interval(rq, p); + } + } - rcu_read_unlock(); jiffies_to_timespec64(time_slice, t); return 0; - -out_unlock: - rcu_read_unlock(); - return retval; } /** @@ -9300,10 +9200,8 @@ int task_can_attach(struct task_struct * * success of set_cpus_allowed_ptr() on all attached tasks * before cpus_mask may be changed. */ - if (p->flags & PF_NO_SETAFFINITY) { - ret = -EINVAL; - goto out; - } + if (p->flags & PF_NO_SETAFFINITY) + return -EINVAL; if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span, cs_effective_cpus)) { @@ -9314,7 +9212,6 @@ int task_can_attach(struct task_struct * ret = dl_cpu_busy(cpu, p); } -out: return ret; } @@ -10464,17 +10361,18 @@ void sched_move_task(struct task_struct int queued, running, queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK; struct task_group *group; - struct rq_flags rf; struct rq *rq; - rq = task_rq_lock(tsk, &rf); + guard(task_rq_lock, guard, tsk); + rq = guard.rq; + /* * Esp. with SCHED_AUTOGROUP enabled it is possible to get superfluous * group changes. */ group = sched_get_task_group(tsk); if (group == tsk->sched_task_group) - goto unlock; + return; update_rq_clock(rq); @@ -10499,9 +10397,6 @@ void sched_move_task(struct task_struct */ resched_curr(rq); } - -unlock: - task_rq_unlock(rq, tsk, &rf); } static inline struct task_group *css_tg(struct cgroup_subsys_state *css) @@ -10538,11 +10433,10 @@ static int cpu_cgroup_css_online(struct #ifdef CONFIG_UCLAMP_TASK_GROUP /* Propagate the effective uclamp value for the new group */ - mutex_lock(&uclamp_mutex); - rcu_read_lock(); - cpu_util_update_eff(css); - rcu_read_unlock(); - mutex_unlock(&uclamp_mutex); + scoped (mutex, &uclamp_mutex) { + guard(rcu, guard); + cpu_util_update_eff(css); + } #endif return 0; @@ -10693,24 +10587,22 @@ static ssize_t cpu_uclamp_write(struct k static_branch_enable(&sched_uclamp_used); - mutex_lock(&uclamp_mutex); - rcu_read_lock(); - - tg = css_tg(of_css(of)); - if (tg->uclamp_req[clamp_id].value != req.util) - uclamp_se_set(&tg->uclamp_req[clamp_id], req.util, false); + scoped (mutex, &uclamp_mutex) { + guard(rcu, guard); - /* - * Because of not recoverable conversion rounding we keep track of the - * exact requested value - */ - tg->uclamp_pct[clamp_id] = req.percent; + tg = css_tg(of_css(of)); + if (tg->uclamp_req[clamp_id].value != req.util) + uclamp_se_set(&tg->uclamp_req[clamp_id], req.util, false); - /* Update effective clamps to track the most restrictive value */ - cpu_util_update_eff(of_css(of)); + /* + * Because of not recoverable conversion rounding we keep track of the + * exact requested value + */ + tg->uclamp_pct[clamp_id] = req.percent; - rcu_read_unlock(); - mutex_unlock(&uclamp_mutex); + /* Update effective clamps to track the most restrictive value */ + cpu_util_update_eff(of_css(of)); + } return nbytes; } @@ -10737,10 +10629,10 @@ static inline void cpu_uclamp_print(stru u64 percent; u32 rem; - rcu_read_lock(); - tg = css_tg(seq_css(sf)); - util_clamp = tg->uclamp_req[clamp_id].value; - rcu_read_unlock(); + scoped (rcu) { + tg = css_tg(seq_css(sf)); + util_clamp = tg->uclamp_req[clamp_id].value; + } if (util_clamp == SCHED_CAPACITY_SCALE) { seq_puts(sf, "max\n"); @@ -10792,6 +10684,8 @@ static const u64 max_cfs_runtime = MAX_B static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); +DEFINE_VOID_GUARD(cpus_read_lock, cpus_read_lock(), cpus_read_unlock()) + static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota, u64 burst) { @@ -10831,53 +10725,54 @@ static int tg_set_cfs_bandwidth(struct t * Prevent race between setting of cfs_rq->runtime_enabled and * unthrottle_offline_cfs_rqs(). */ - cpus_read_lock(); - mutex_lock(&cfs_constraints_mutex); - ret = __cfs_schedulable(tg, period, quota); - if (ret) - goto out_unlock; + scoped (cpus_read_lock) { + guard(mutex, guard, &cfs_constraints_mutex); - runtime_enabled = quota != RUNTIME_INF; - runtime_was_enabled = cfs_b->quota != RUNTIME_INF; - /* - * If we need to toggle cfs_bandwidth_used, off->on must occur - * before making related changes, and on->off must occur afterwards - */ - if (runtime_enabled && !runtime_was_enabled) - cfs_bandwidth_usage_inc(); - raw_spin_lock_irq(&cfs_b->lock); - cfs_b->period = ns_to_ktime(period); - cfs_b->quota = quota; - cfs_b->burst = burst; - - __refill_cfs_bandwidth_runtime(cfs_b); - - /* Restart the period timer (if active) to handle new period expiry: */ - if (runtime_enabled) - start_cfs_bandwidth(cfs_b); - - raw_spin_unlock_irq(&cfs_b->lock); - - for_each_online_cpu(i) { - struct cfs_rq *cfs_rq = tg->cfs_rq[i]; - struct rq *rq = cfs_rq->rq; - struct rq_flags rf; - - rq_lock_irq(rq, &rf); - cfs_rq->runtime_enabled = runtime_enabled; - cfs_rq->runtime_remaining = 0; - - if (cfs_rq->throttled) - unthrottle_cfs_rq(cfs_rq); - rq_unlock_irq(rq, &rf); + ret = __cfs_schedulable(tg, period, quota); + if (ret) + return ret; + + runtime_enabled = quota != RUNTIME_INF; + runtime_was_enabled = cfs_b->quota != RUNTIME_INF; + /* + * If we need to toggle cfs_bandwidth_used, off->on must occur + * before making related changes, and on->off must occur afterwards + */ + if (runtime_enabled && !runtime_was_enabled) + cfs_bandwidth_usage_inc(); + + scoped (raw_spinlock_irq, &cfs_b->lock) { + cfs_b->period = ns_to_ktime(period); + cfs_b->quota = quota; + cfs_b->burst = burst; + + __refill_cfs_bandwidth_runtime(cfs_b); + + /* + * Restart the period timer (if active) to handle new + * period expiry: + */ + if (runtime_enabled) + start_cfs_bandwidth(cfs_b); + } + + for_each_online_cpu(i) { + struct cfs_rq *cfs_rq = tg->cfs_rq[i]; + struct rq *rq = cfs_rq->rq; + + scoped (rq_lock_irq, rq) { + cfs_rq->runtime_enabled = runtime_enabled; + cfs_rq->runtime_remaining = 0; + + if (cfs_rq->throttled) + unthrottle_cfs_rq(cfs_rq); + } + } + if (runtime_was_enabled && !runtime_enabled) + cfs_bandwidth_usage_dec(); } - if (runtime_was_enabled && !runtime_enabled) - cfs_bandwidth_usage_dec(); -out_unlock: - mutex_unlock(&cfs_constraints_mutex); - cpus_read_unlock(); - return ret; + return 0; } static int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) @@ -11069,9 +10964,8 @@ static int __cfs_schedulable(struct task do_div(data.quota, NSEC_PER_USEC); } - rcu_read_lock(); - ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); - rcu_read_unlock(); + scoped (rcu) + ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); return ret; } @@ -11634,14 +11528,13 @@ int __sched_mm_cid_migrate_from_fetch_ci * are not the last task to be migrated from this cpu for this mm, so * there is no need to move src_cid to the destination cpu. */ - rcu_read_lock(); - src_task = rcu_dereference(src_rq->curr); - if (READ_ONCE(src_task->mm_cid_active) && src_task->mm == mm) { - rcu_read_unlock(); - t->last_mm_cid = -1; - return -1; + scoped (rcu) { + src_task = rcu_dereference(src_rq->curr); + if (READ_ONCE(src_task->mm_cid_active) && src_task->mm == mm) { + t->last_mm_cid = -1; + return -1; + } } - rcu_read_unlock(); return src_cid; } @@ -11685,18 +11578,17 @@ int __sched_mm_cid_migrate_from_try_stea * the lazy-put flag, this task will be responsible for transitioning * from lazy-put flag set to MM_CID_UNSET. */ - rcu_read_lock(); - src_task = rcu_dereference(src_rq->curr); - if (READ_ONCE(src_task->mm_cid_active) && src_task->mm == mm) { - rcu_read_unlock(); - /* - * We observed an active task for this mm, there is therefore - * no point in moving this cid to the destination cpu. - */ - t->last_mm_cid = -1; - return -1; + scoped (rcu) { + src_task = rcu_dereference(src_rq->curr); + if (READ_ONCE(src_task->mm_cid_active) && src_task->mm == mm) { + /* + * We observed an active task for this mm, there is therefore + * no point in moving this cid to the destination cpu. + */ + t->last_mm_cid = -1; + return -1; + } } - rcu_read_unlock(); /* * The src_cid is unused, so it can be unset. @@ -11769,7 +11661,6 @@ static void sched_mm_cid_remote_clear(st { struct rq *rq = cpu_rq(cpu); struct task_struct *t; - unsigned long flags; int cid, lazy_cid; cid = READ_ONCE(pcpu_cid->cid); @@ -11804,23 +11695,21 @@ static void sched_mm_cid_remote_clear(st * the lazy-put flag, that task will be responsible for transitioning * from lazy-put flag set to MM_CID_UNSET. */ - rcu_read_lock(); - t = rcu_dereference(rq->curr); - if (READ_ONCE(t->mm_cid_active) && t->mm == mm) { - rcu_read_unlock(); - return; + scoped (rcu) { + t = rcu_dereference(rq->curr); + if (READ_ONCE(t->mm_cid_active) && t->mm == mm) + return; } - rcu_read_unlock(); /* * The cid is unused, so it can be unset. * Disable interrupts to keep the window of cid ownership without rq * lock small. */ - local_irq_save(flags); - if (try_cmpxchg(&pcpu_cid->cid, &lazy_cid, MM_CID_UNSET)) - __mm_cid_put(mm, cid); - local_irq_restore(flags); + scoped (irqsave) { + if (try_cmpxchg(&pcpu_cid->cid, &lazy_cid, MM_CID_UNSET)) + __mm_cid_put(mm, cid); + } } static void sched_mm_cid_remote_clear_old(struct mm_struct *mm, int cpu) @@ -11842,14 +11731,13 @@ static void sched_mm_cid_remote_clear_ol * snapshot associated with this cid if an active task using the mm is * observed on this rq. */ - rcu_read_lock(); - curr = rcu_dereference(rq->curr); - if (READ_ONCE(curr->mm_cid_active) && curr->mm == mm) { - WRITE_ONCE(pcpu_cid->time, rq_clock); - rcu_read_unlock(); - return; + scoped (rcu) { + curr = rcu_dereference(rq->curr); + if (READ_ONCE(curr->mm_cid_active) && curr->mm == mm) { + WRITE_ONCE(pcpu_cid->time, rq_clock); + return; + } } - rcu_read_unlock(); if (rq_clock < pcpu_cid->time + SCHED_MM_CID_PERIOD_NS) return; @@ -11943,7 +11831,6 @@ void task_tick_mm_cid(struct rq *rq, str void sched_mm_cid_exit_signals(struct task_struct *t) { struct mm_struct *mm = t->mm; - struct rq_flags rf; struct rq *rq; if (!mm) @@ -11951,23 +11838,22 @@ void sched_mm_cid_exit_signals(struct ta preempt_disable(); rq = this_rq(); - rq_lock_irqsave(rq, &rf); - preempt_enable_no_resched(); /* holding spinlock */ - WRITE_ONCE(t->mm_cid_active, 0); - /* - * Store t->mm_cid_active before loading per-mm/cpu cid. - * Matches barrier in sched_mm_cid_remote_clear_old(). - */ - smp_mb(); - mm_cid_put(mm); - t->last_mm_cid = t->mm_cid = -1; - rq_unlock_irqrestore(rq, &rf); + scoped (rq_lock_irqsave, rq) { + preempt_enable_no_resched(); /* holding spinlock */ + WRITE_ONCE(t->mm_cid_active, 0); + /* + * Store t->mm_cid_active before loading per-mm/cpu cid. + * Matches barrier in sched_mm_cid_remote_clear_old(). + */ + smp_mb(); + mm_cid_put(mm); + t->last_mm_cid = t->mm_cid = -1; + } } void sched_mm_cid_before_execve(struct task_struct *t) { struct mm_struct *mm = t->mm; - struct rq_flags rf; struct rq *rq; if (!mm) @@ -11975,23 +11861,22 @@ void sched_mm_cid_before_execve(struct t preempt_disable(); rq = this_rq(); - rq_lock_irqsave(rq, &rf); - preempt_enable_no_resched(); /* holding spinlock */ - WRITE_ONCE(t->mm_cid_active, 0); - /* - * Store t->mm_cid_active before loading per-mm/cpu cid. - * Matches barrier in sched_mm_cid_remote_clear_old(). - */ - smp_mb(); - mm_cid_put(mm); - t->last_mm_cid = t->mm_cid = -1; - rq_unlock_irqrestore(rq, &rf); + scoped (rq_lock_irqsave, rq) { + preempt_enable_no_resched(); /* holding spinlock */ + WRITE_ONCE(t->mm_cid_active, 0); + /* + * Store t->mm_cid_active before loading per-mm/cpu cid. + * Matches barrier in sched_mm_cid_remote_clear_old(). + */ + smp_mb(); + mm_cid_put(mm); + t->last_mm_cid = t->mm_cid = -1; + } } void sched_mm_cid_after_execve(struct task_struct *t) { struct mm_struct *mm = t->mm; - struct rq_flags rf; struct rq *rq; if (!mm) @@ -11999,16 +11884,16 @@ void sched_mm_cid_after_execve(struct ta preempt_disable(); rq = this_rq(); - rq_lock_irqsave(rq, &rf); - preempt_enable_no_resched(); /* holding spinlock */ - WRITE_ONCE(t->mm_cid_active, 1); - /* - * Store t->mm_cid_active before loading per-mm/cpu cid. - * Matches barrier in sched_mm_cid_remote_clear_old(). - */ - smp_mb(); - t->last_mm_cid = t->mm_cid = mm_cid_get(rq, mm); - rq_unlock_irqrestore(rq, &rf); + scoped (rq_lock_irqsave, rq) { + preempt_enable_no_resched(); /* holding spinlock */ + WRITE_ONCE(t->mm_cid_active, 1); + /* + * Store t->mm_cid_active before loading per-mm/cpu cid. + * Matches barrier in sched_mm_cid_remote_clear_old(). + */ + smp_mb(); + t->last_mm_cid = t->mm_cid = mm_cid_get(rq, mm); + } rseq_set_notify_resume(t); } --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1630,6 +1630,11 @@ task_rq_unlock(struct rq *rq, struct tas raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags); } +DEFINE_LOCK_GUARD_1(task_rq_lock, struct task_struct, + _G->rq = task_rq_lock(_G->lock, &_G->rf), + task_rq_unlock(_G->rq, _G->lock, &_G->rf), + struct rq *rq; struct rq_flags rf) + static inline void rq_lock_irqsave(struct rq *rq, struct rq_flags *rf) __acquires(rq->lock) @@ -1678,6 +1683,21 @@ rq_unlock(struct rq *rq, struct rq_flags raw_spin_rq_unlock(rq); } +DEFINE_LOCK_GUARD_1(rq_lock, struct rq, + rq_lock(_G->lock, &_G->rf), + rq_unlock(_G->lock, &_G->rf), + struct rq_flags rf) + +DEFINE_LOCK_GUARD_1(rq_lock_irq, struct rq, + rq_lock_irq(_G->lock, &_G->rf), + rq_unlock_irq(_G->lock, &_G->rf), + struct rq_flags rf) + +DEFINE_LOCK_GUARD_1(rq_lock_irqsave, struct rq, + rq_lock_irqsave(_G->lock, &_G->rf), + rq_unlock_irqrestore(_G->lock, &_G->rf), + struct rq_flags rf) + static inline struct rq * this_rq_lock_irq(struct rq_flags *rf) __acquires(rq->lock) @@ -2701,6 +2721,16 @@ static inline void double_raw_lock(raw_s raw_spin_lock_nested(l2, SINGLE_DEPTH_NESTING); } +static inline void double_raw_unlock(raw_spinlock_t *l1, raw_spinlock_t *l2) +{ + raw_spin_unlock(l1); + raw_spin_unlock(l2); +} + +DEFINE_LOCK_GUARD_2(double_raw_spinlock, raw_spinlock_t, + double_raw_lock(_G->lock, _G->lock2), + double_raw_unlock(_G->lock, _G->lock2)) + /* * double_rq_unlock - safely unlock two runqueues * @@ -2758,6 +2788,10 @@ static inline void double_rq_unlock(stru #endif +DEFINE_LOCK_GUARD_2(double_rq_lock, struct rq, + double_rq_lock(_G->lock, _G->lock2), + double_rq_unlock(_G->lock, _G->lock2)) + extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq); extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq);