From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
rostedt@goodmis.org, Yury Norov <yury.norov@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 9/9] rcu: Replace cpumask_weight with cpumask_empty where appropriate
Date: Fri, 4 Feb 2022 15:08:05 -0800 [thread overview]
Message-ID: <20220204230805.4193767-9-paulmck@kernel.org> (raw)
In-Reply-To: <20220204230751.GA4193671@paulmck-ThinkPad-P17-Gen-1>
From: Yury Norov <yury.norov@gmail.com>
In some places, RCU code calls cpumask_weight() to check if any bit of a
given cpumask is set. We can do it more efficiently with cpumask_empty()
because cpumask_empty() stops traversing the cpumask as soon as it finds
first set bit, while cpumask_weight() counts all bits unconditionally.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tree_nocb.h | 4 ++--
kernel/rcu/tree_plugin.h | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index eeafb546a7a09..f83c7b1d61103 100644
--- a/kernel/rcu/tree_nocb.h
+++ b/kernel/rcu/tree_nocb.h
@@ -1169,7 +1169,7 @@ void __init rcu_init_nohz(void)
struct rcu_data *rdp;
#if defined(CONFIG_NO_HZ_FULL)
- if (tick_nohz_full_running && cpumask_weight(tick_nohz_full_mask))
+ if (tick_nohz_full_running && !cpumask_empty(tick_nohz_full_mask))
need_rcu_nocb_mask = true;
#endif /* #if defined(CONFIG_NO_HZ_FULL) */
@@ -1348,7 +1348,7 @@ static void __init rcu_organize_nocb_kthreads(void)
*/
void rcu_bind_current_to_nocb(void)
{
- if (cpumask_available(rcu_nocb_mask) && cpumask_weight(rcu_nocb_mask))
+ if (cpumask_available(rcu_nocb_mask) && !cpumask_empty(rcu_nocb_mask))
WARN_ON(sched_setaffinity(current->pid, rcu_nocb_mask));
}
EXPORT_SYMBOL_GPL(rcu_bind_current_to_nocb);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 07845dcd33c5e..efd0c87d2ffae 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1220,7 +1220,7 @@ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
cpu != outgoingcpu)
cpumask_set_cpu(cpu, cm);
cpumask_and(cm, cm, housekeeping_cpumask(HK_FLAG_RCU));
- if (cpumask_weight(cm) == 0)
+ if (cpumask_empty(cm))
cpumask_copy(cm, housekeeping_cpumask(HK_FLAG_RCU));
set_cpus_allowed_ptr(t, cm);
mutex_unlock(&rnp->boost_kthread_mutex);
--
2.31.1.189.g2e36527f23
next prev parent reply other threads:[~2022-02-04 23:08 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 23:07 [PATCH rcu 0/9] Miscellaneous fixes for v5.18 Paul E. McKenney
2022-02-04 23:07 ` [PATCH rcu 1/9] MAINTAINERS: Add Frederic and Neeraj to their RCU files Paul E. McKenney
2022-02-11 15:15 ` Frederic Weisbecker
2022-02-11 16:40 ` Paul E. McKenney
2022-02-04 23:07 ` [PATCH rcu 2/9] rcu: Fix description of kvfree_rcu() Paul E. McKenney
2022-02-04 23:07 ` [PATCH rcu 3/9] rcu: Add mutex for rcu boost kthread spawning and affinity setting Paul E. McKenney
2022-02-11 14:57 ` Frederic Weisbecker
2022-02-11 15:11 ` Frederic Weisbecker
2022-02-11 15:42 ` Paul E. McKenney
2022-02-11 15:43 ` Frederic Weisbecker
2022-02-04 23:08 ` [PATCH rcu 4/9] rcu: Inline __call_rcu() into call_rcu() Paul E. McKenney
2022-02-04 23:08 ` [PATCH rcu 5/9] kasan: Record work creation stack trace with interrupts enabled Paul E. McKenney
2022-02-04 23:08 ` [PATCH rcu 6/9] rcu: Mark writes to the rcu_segcblist structure's ->flags field Paul E. McKenney
2022-02-04 23:08 ` [PATCH rcu 7/9] rcu: Uninline multi-use function: finish_rcuwait() Paul E. McKenney
2022-02-04 23:08 ` [PATCH rcu 8/9] rcu: Remove __read_mostly annotations from rcu_scheduler_active externs Paul E. McKenney
2022-02-04 23:08 ` Paul E. McKenney [this message]
2022-02-11 15:17 ` [PATCH rcu 9/9] rcu: Replace cpumask_weight with cpumask_empty where appropriate Frederic Weisbecker
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