From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 3/6] kvfree_rcu: Make krc_this_cpu_unlock() use raw_spin_unlock_irqrestore()
Date: Wed, 3 Mar 2021 16:11:31 -0800 [thread overview]
Message-ID: <20210304001134.22977-3-paulmck@kernel.org> (raw)
In-Reply-To: <20210304001044.GA22871@paulmck-ThinkPad-P72>
From: "Paul E. McKenney" <paulmck@kernel.org>
The krc_this_cpu_unlock() function does a raw_spin_unlock() immediately
followed by a local_irq_restore(). This commit saves a line of code by
merging them into a raw_spin_unlock_irqrestore(). This transformation
also reduces scheduling latency because raw_spin_unlock_irqrestore()
responds immediately to a reschedule request. In contrast,
local_irq_restore() does a scheduling-oblivious enabling of interrupts.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tree.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 08b5044..7ee83f3 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3229,8 +3229,7 @@ krc_this_cpu_lock(unsigned long *flags)
static inline void
krc_this_cpu_unlock(struct kfree_rcu_cpu *krcp, unsigned long flags)
{
- raw_spin_unlock(&krcp->lock);
- local_irq_restore(flags);
+ raw_spin_unlock_irqrestore(&krcp->lock, flags);
}
static inline struct kvfree_rcu_bulk_data *
--
2.9.5
next prev parent reply other threads:[~2021-03-04 0:18 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 0:10 [PATCH tip/core/rcu 0/6] kvfree_rcu() updates for v5.12-rc1 Paul E. McKenney
2021-03-04 0:11 ` [PATCH tip/core/rcu 1/6] kvfree_rcu: Directly allocate page for single-argument case paulmck
2021-03-04 0:11 ` [PATCH tip/core/rcu 2/6] kvfree_rcu: Use __GFP_NOMEMALLOC for single-argument kvfree_rcu() paulmck
2021-03-04 0:11 ` paulmck [this message]
2021-03-04 0:11 ` [PATCH tip/core/rcu 4/6] kvfree_rcu: Replace __GFP_RETRY_MAYFAIL by __GFP_NORETRY paulmck
2021-03-04 0:11 ` [PATCH tip/core/rcu 5/6] kvfree_rcu: Use same set of GFP flags as does single-argument paulmck
2021-03-04 0:11 ` [PATCH tip/core/rcu 6/6] rcuscale: Add kfree_rcu() single-argument scale test paulmck
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