From patchwork Mon Jun 12 09:07:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 13276189 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 C9401C7EE2E for ; Mon, 12 Jun 2023 09:58:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230408AbjFLJ6e (ORCPT ); Mon, 12 Jun 2023 05:58:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33560 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233425AbjFLJyp (ORCPT ); Mon, 12 Jun 2023 05:54:45 -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 A5F334C1D; Mon, 12 Jun 2023 02:39:07 -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=szAn79F4mqfMUFH3NFua/nTnj8aGUQ8HGVR6NlJOzM4=; b=dmt6RRN5/6iW0nXv8WCs7Zhoq7 h66/OFpGSYq3NopaotDNajuFo8i5Abvywbk25Mkw64F7BKRPBDAMFErpkMVn5jc1JDWWixleXtBPh TLPcdD6pTKzi2NGzuw4ny2PmQy/30yIqkBkkgI2XhvaBJgwGgdhaI4B8DWmnMj2mqvkcRzcAY6HRy jk7gpJD/ftYk8Hikh4m2P22vJKm9NoD09zIFAZMUbUi4MpR8Yhp4gzJ6D7tuejbq/RRvcSqn4CrlB sEMwyssBIPsqrQMHjdIJ8/AZRnWyKMbTE7D2j2333TyWpvcfxe9q1zhpgbPY6ZV8UERchXfhjI06e QRlB8Skw==; 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 1q8e0l-008kQP-0j; Mon, 12 Jun 2023 09:38:56 +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)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 0E96F302F7E; Mon, 12 Jun 2023 11:38:53 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 6C74530A77B5C; Mon, 12 Jun 2023 11:38:48 +0200 (CEST) Message-ID: <20230612093539.014199820@infradead.org> User-Agent: quilt/0.66 Date: Mon, 12 Jun 2023 11:07:34 +0200 From: Peter Zijlstra To: torvalds@linux-foundation.org, keescook@chromium.org, gregkh@linuxfoundation.org, pbonzini@redhat.com Cc: masahiroy@kernel.org, nathan@kernel.org, ndesaulniers@google.com, nicolas@fjasle.eu, catalin.marinas@arm.com, will@kernel.org, vkoul@kernel.org, trix@redhat.com, ojeda@kernel.org, peterz@infradead.org, mingo@redhat.com, longman@redhat.com, boqun.feng@gmail.com, dennis@kernel.org, tj@kernel.org, cl@linux.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, adrian.hunter@intel.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, rientjes@google.com, vbabka@suse.cz, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, apw@canonical.com, joe@perches.com, dwaipayanray1@gmail.com, lukas.bulwahn@gmail.com, john.johansen@canonical.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, llvm@lists.linux.dev, linux-perf-users@vger.kernel.org, rcu@vger.kernel.org, linux-security-module@vger.kernel.org, tglx@linutronix.de, ravi.bangoria@amd.com, error27@gmail.com, luc.vanoostenryck@gmail.com Subject: [PATCH v3 21/57] sched: Misc cleanups References: <20230612090713.652690195@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org Random remaining guard use... Signed-off-by: Peter Zijlstra (Intel) --- kernel/sched/core.c | 163 ++++++++++++++++++++-------------------------------- 1 file changed, 63 insertions(+), 100 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1454,16 +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); + guard(task_rq_lock)(p); __uclamp_update_util_min_rt_default(p); - task_rq_unlock(rq, p, &rf); } static inline struct uclamp_se @@ -1759,9 +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(); + guard(rcu)(); cpu_util_update_eff(&root_task_group.css); - rcu_read_unlock(); } #else static void uclamp_update_root_tg(void) { } @@ -1788,10 +1783,9 @@ static void uclamp_sync_util_min_rt_defa smp_mb__after_spinlock(); read_unlock(&tasklist_lock); - rcu_read_lock(); + guard(rcu)(); for_each_process_thread(g, p) uclamp_update_util_min_rt_default(p); - rcu_read_unlock(); } static int sysctl_sched_uclamp_handler(struct ctl_table *table, int write, @@ -2243,10 +2237,9 @@ void migrate_disable(void) return; } - preempt_disable(); + guard(preempt)(); this_rq()->nr_pinned++; p->migration_disabled = 1; - preempt_enable(); } EXPORT_SYMBOL_GPL(migrate_disable); @@ -2270,7 +2263,7 @@ 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(); + guard(preempt)(); if (p->cpus_ptr != &p->cpus_mask) __set_cpus_allowed_ptr(p, &ac); /* @@ -2281,7 +2274,6 @@ void migrate_enable(void) barrier(); p->migration_disabled = 0; this_rq()->nr_pinned--; - preempt_enable(); } EXPORT_SYMBOL_GPL(migrate_enable); @@ -3449,13 +3441,11 @@ unsigned long wait_task_inactive(struct */ void kick_process(struct task_struct *p) { - int cpu; + guard(preempt)(); + 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); @@ -6300,8 +6290,9 @@ static void sched_core_balance(struct rq struct sched_domain *sd; int cpu = cpu_of(rq); - preempt_disable(); - rcu_read_lock(); + guard(preempt)(); + guard(rcu)(); + raw_spin_rq_unlock_irq(rq); for_each_domain(cpu, sd) { if (need_resched()) @@ -6311,8 +6302,6 @@ 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); @@ -8169,8 +8158,6 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pi #ifdef CONFIG_SMP int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask) { - int ret = 0; - /* * If the task isn't a deadline task or admission control is * disabled then we don't care about affinity changes. @@ -8184,11 +8171,11 @@ 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(); + guard(rcu)(); if (!cpumask_subset(task_rq(p)->rd->span, mask)) - ret = -EBUSY; - rcu_read_unlock(); - return ret; + return -EBUSY; + + return 0; } #endif @@ -9197,10 +9184,8 @@ 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)) { @@ -9211,7 +9196,6 @@ int task_can_attach(struct task_struct * ret = dl_cpu_busy(cpu, p); } -out: return ret; } @@ -10433,11 +10417,9 @@ 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(); + guard(mutex)(&uclamp_mutex); + guard(rcu)(); cpu_util_update_eff(css); - rcu_read_unlock(); - mutex_unlock(&uclamp_mutex); #endif return 0; @@ -10588,8 +10570,8 @@ static ssize_t cpu_uclamp_write(struct k static_branch_enable(&sched_uclamp_used); - mutex_lock(&uclamp_mutex); - rcu_read_lock(); + guard(mutex)(&uclamp_mutex); + guard(rcu)(); tg = css_tg(of_css(of)); if (tg->uclamp_req[clamp_id].value != req.util) @@ -10604,9 +10586,6 @@ static ssize_t cpu_uclamp_write(struct k /* Update effective clamps to track the most restrictive value */ cpu_util_update_eff(of_css(of)); - rcu_read_unlock(); - mutex_unlock(&uclamp_mutex); - return nbytes; } @@ -10632,10 +10611,10 @@ 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_guard (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"); @@ -10952,7 +10931,6 @@ static int tg_cfs_schedulable_down(struc static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) { - int ret; struct cfs_schedulable_data data = { .tg = tg, .period = period, @@ -10964,11 +10942,8 @@ 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(); - - return ret; + guard(rcu)(); + return walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); } static int cpu_cfs_stat_show(struct seq_file *sf, void *v) @@ -11529,14 +11504,12 @@ 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(); + guard(rcu)(); 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; } - rcu_read_unlock(); return src_cid; } @@ -11580,18 +11553,17 @@ 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_guard (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. @@ -11664,7 +11636,6 @@ 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); @@ -11699,23 +11670,21 @@ 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_guard (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_guard (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) @@ -11737,14 +11706,13 @@ 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_guard (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; @@ -11838,7 +11806,6 @@ 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) @@ -11846,7 +11813,7 @@ void sched_mm_cid_exit_signals(struct ta preempt_disable(); rq = this_rq(); - rq_lock_irqsave(rq, &rf); + guard(rq_lock_irqsave)(rq); preempt_enable_no_resched(); /* holding spinlock */ WRITE_ONCE(t->mm_cid_active, 0); /* @@ -11856,13 +11823,11 @@ void sched_mm_cid_exit_signals(struct ta smp_mb(); mm_cid_put(mm); t->last_mm_cid = t->mm_cid = -1; - rq_unlock_irqrestore(rq, &rf); } 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) @@ -11870,7 +11835,7 @@ void sched_mm_cid_before_execve(struct t preempt_disable(); rq = this_rq(); - rq_lock_irqsave(rq, &rf); + guard(rq_lock_irqsave)(rq); preempt_enable_no_resched(); /* holding spinlock */ WRITE_ONCE(t->mm_cid_active, 0); /* @@ -11880,13 +11845,11 @@ void sched_mm_cid_before_execve(struct t smp_mb(); mm_cid_put(mm); t->last_mm_cid = t->mm_cid = -1; - rq_unlock_irqrestore(rq, &rf); } 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) @@ -11894,16 +11857,16 @@ 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_guard (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); }