From 337e9b07db3b8c7f7d68b849df32f434a1a3b831 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 6 Nov 2018 19:10:53 -0800 Subject: sched: Replace call_rcu_sched() with call_rcu() Now that call_rcu()'s callback is not invoked until after all preempt-disable regions of code have completed (in addition to explicitly marked RCU read-side critical sections), call_rcu() can be used in place of call_rcu_sched(). This commit therefore makes that change. While in the area, this commit also updates an outdated header comment for for_each_domain(). Signed-off-by: Paul E. McKenney Cc: Ingo Molnar Cc: Peter Zijlstra --- kernel/sched/sched.h | 2 +- kernel/sched/topology.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d04530bf251f..6665b9c02e2f 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1260,7 +1260,7 @@ extern void sched_ttwu_pending(void); /* * The domain tree (rq->sd) is protected by RCU's quiescent state transition. - * See detach_destroy_domains: synchronize_sched for details. + * See destroy_sched_domains: call_rcu for details. * * The domain tree of any CPU may only be accessed from within * preempt-disabled sections. diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 3f35ba1d8fde..7d905f55e7fa 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -442,7 +442,7 @@ void rq_attach_root(struct rq *rq, struct root_domain *rd) raw_spin_unlock_irqrestore(&rq->lock, flags); if (old_rd) - call_rcu_sched(&old_rd->rcu, free_rootdomain); + call_rcu(&old_rd->rcu, free_rootdomain); } void sched_get_rd(struct root_domain *rd) @@ -455,7 +455,7 @@ void sched_put_rd(struct root_domain *rd) if (!atomic_dec_and_test(&rd->refcount)) return; - call_rcu_sched(&rd->rcu, free_rootdomain); + call_rcu(&rd->rcu, free_rootdomain); } static int init_rootdomain(struct root_domain *rd) -- cgit From b290ebcf7bc4638b38c413f192963f4b74e45b7b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 6 Nov 2018 19:13:54 -0800 Subject: sched: Replace synchronize_sched() with synchronize_rcu() Now that synchronize_rcu() waits for preempt-disable regions of code as well as RCU read-side critical sections, synchronize_sched() can be replaced by synchronize_rcu(), in fact, synchronize_sched() is now completely equivalent to synchronize_rcu(). This commit therefore replaces synchronize_sched() with synchronize_rcu() so that synchronize_sched() can eventually be removed entirely. Signed-off-by: Paul E. McKenney Cc: Ingo Molnar Cc: Peter Zijlstra --- kernel/sched/cpufreq.c | 4 ++-- kernel/sched/cpufreq_schedutil.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c index 22bd8980f32f..835671f0f917 100644 --- a/kernel/sched/cpufreq.c +++ b/kernel/sched/cpufreq.c @@ -48,8 +48,8 @@ EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook); * * Clear the update_util_data pointer for the given CPU. * - * Callers must use RCU-sched callbacks to free any memory that might be - * accessed via the old update_util_data pointer or invoke synchronize_sched() + * Callers must use RCU callbacks to free any memory that might be + * accessed via the old update_util_data pointer or invoke synchronize_rcu() * right after this function to avoid use-after-free. */ void cpufreq_remove_update_util_hook(int cpu) diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 033ec7c45f13..2efe629425be 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -859,7 +859,7 @@ static void sugov_stop(struct cpufreq_policy *policy) for_each_cpu(cpu, policy->cpus) cpufreq_remove_update_util_hook(cpu); - synchronize_sched(); + synchronize_rcu(); if (!policy->fast_switch_enabled) { irq_work_sync(&sg_policy->irq_work); -- cgit