From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.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,
Lihao Liang <lianglihao@huawei.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 01/20] rcu: Remove unnecessary spinlock in rcu_boot_init_percpu_data()
Date: Mon, 26 Feb 2018 13:52:51 -0800 [thread overview]
Message-ID: <1519681990-31349-1-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180226215219.GA27379@linux.vnet.ibm.com>
From: Lihao Liang <lianglihao@huawei.com>
Since rcu_boot_init_percpu_data() is only called at boot time,
there is no data race and spinlock is not needed.
Signed-off-by: Lihao Liang <lianglihao@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcu/tree.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 491bdf39f276..66c73a214cff 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3636,12 +3636,9 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
static void __init
rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
{
- unsigned long flags;
struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
- struct rcu_node *rnp = rcu_get_root(rsp);
/* Set up local state, ensuring consistent view of global state. */
- raw_spin_lock_irqsave_rcu_node(rnp, flags);
rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu);
rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != 1);
@@ -3649,7 +3646,6 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
rdp->cpu = cpu;
rdp->rsp = rsp;
rcu_boot_init_nocb_percpu_data(rdp);
- raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
/*
--
2.5.2
next prev parent reply other threads:[~2018-02-26 21:52 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-26 21:52 [PATCH tip/core/rcu 0/20] Miscellaneous fixes Paul E. McKenney
2018-02-26 21:52 ` Paul E. McKenney [this message]
2018-02-26 21:52 ` [PATCH tip/core/rcu 02/20] sched/isolation: Eliminate NO_HZ_FULL_ALL Paul E. McKenney
2018-02-26 21:52 ` [PATCH tip/core/rcu 03/20] rcu: Fix CPU offload boot message when no CPUs are offloaded Paul E. McKenney
2018-02-26 21:52 ` [PATCH tip/core/rcu 04/20] doc: Fix typo in rcutorture documentation Paul E. McKenney
2018-02-26 21:52 ` [PATCH tip/core/rcu 05/20] doc: Fix typo in rcu_head comments Paul E. McKenney
2018-02-26 21:52 ` [PATCH tip/core/rcu 06/20] rcu: Call touch_nmi_watchdog() while printing stall warnings Paul E. McKenney
2018-02-26 21:52 ` [PATCH tip/core/rcu 07/20] rcu: Remove obsolete boost statistics for debugfs Paul E. McKenney
2018-02-26 21:52 ` [PATCH tip/core/rcu 08/20] rcu: Remove obsolete callback-invocation " Paul E. McKenney
2018-02-26 21:52 ` [PATCH tip/core/rcu 09/20] rcu: Remove obsolete __rcu_pending() " Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 10/20] rcu: Remove obsolete force-quiescent-state " Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 11/20] rcu: More clearly identify grace-period kthread stack dump Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 12/20] rcu: Consolidate rcu.h #ifdefs Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 13/20] rcu: Remove redundant nxttail index macro define Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 14/20] rcu: Use wrapper for lockdep asserts Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 15/20] rcu: Fix init_rcu_head() comment Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 16/20] rcu: Fix misprint in srcu_funnel_exp_start Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 17/20] rcu: Add more tracing of expedited grace periods Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 18/20] rcu: Trace expedited GP delays due to transitioning CPUs Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 19/20] rcu: Make expedited RCU CPU selection avoid unnecessary stores Paul E. McKenney
2018-02-26 21:53 ` [PATCH tip/core/rcu 20/20] rcu: Create RCU-specific workqueues with rescuers Paul E. McKenney
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