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, 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, joel@joelfernandes.org,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Uladzislau Rezki <urezki@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 08/17] rcu/tree: Use static initializer for krc.lock
Date: Wed, 24 Jun 2020 13:12:17 -0700 [thread overview]
Message-ID: <20200624201226.21197-8-paulmck@kernel.org> (raw)
In-Reply-To: <20200624201200.GA28901@paulmck-ThinkPad-P72>
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
The per-CPU variable is initialized at runtime in
kfree_rcu_batch_init(). This function is invoked before
'rcu_scheduler_active' is set to 'RCU_SCHEDULER_RUNNING'.
After the initialisation, '->initialized' is to true.
The raw_spin_lock is only acquired if '->initialized' is
set to true. The worqueue item is only used if 'rcu_scheduler_active'
set to RCU_SCHEDULER_RUNNING which happens after initialisation.
Use a static initializer for krc.lock and remove the runtime
initialisation of the lock. Since the lock can now be always
acquired, remove the '->initialized' check.
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tree.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index edc512e..4fba1e9 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2984,7 +2984,7 @@ struct kfree_rcu_cpu_work {
* @lock: Synchronize access to this structure
* @monitor_work: Promote @head to @head_free after KFREE_DRAIN_JIFFIES
* @monitor_todo: Tracks whether a @monitor_work delayed work is pending
- * @initialized: The @lock and @rcu_work fields have been initialized
+ * @initialized: The @rcu_work fields have been initialized
* @count: Number of objects for which GP not started
*
* This is a per-CPU structure. The reason that it is not included in
@@ -3004,7 +3004,9 @@ struct kfree_rcu_cpu {
int count;
};
-static DEFINE_PER_CPU(struct kfree_rcu_cpu, krc);
+static DEFINE_PER_CPU(struct kfree_rcu_cpu, krc) = {
+ .lock = __RAW_SPIN_LOCK_UNLOCKED(krc.lock),
+};
static __always_inline void
debug_rcu_bhead_unqueue(struct kfree_rcu_bulk_data *bhead)
@@ -3024,8 +3026,7 @@ krc_this_cpu_lock(unsigned long *flags)
local_irq_save(*flags); // For safely calling this_cpu_ptr().
krcp = this_cpu_ptr(&krc);
- if (likely(krcp->initialized))
- raw_spin_lock(&krcp->lock);
+ raw_spin_lock(&krcp->lock);
return krcp;
}
@@ -3033,8 +3034,7 @@ krc_this_cpu_lock(unsigned long *flags)
static inline void
krc_this_cpu_unlock(struct kfree_rcu_cpu *krcp, unsigned long flags)
{
- if (likely(krcp->initialized))
- raw_spin_unlock(&krcp->lock);
+ raw_spin_unlock(&krcp->lock);
local_irq_restore(flags);
}
@@ -4260,7 +4260,6 @@ static void __init kfree_rcu_batch_init(void)
for_each_possible_cpu(cpu) {
struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
- raw_spin_lock_init(&krcp->lock);
for (i = 0; i < KFREE_N_BATCHES; i++) {
INIT_RCU_WORK(&krcp->krw_arr[i].rcu_work, kfree_rcu_work);
krcp->krw_arr[i].krcp = krcp;
--
2.9.5
next prev parent reply other threads:[~2020-06-24 20:13 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 20:12 [PATCH tip/core/rcu 0/17] kfree_rcu updates for v5.9 Paul E. McKenney
2020-06-24 20:12 ` [PATCH tip/core/rcu 01/17] rcu: Fix a kernel-doc warnings for "count" paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 02/17] rcu/tree: Keep kfree_rcu() awake during lock contention paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 03/17] rcu/tree: Skip entry into the page allocator for PREEMPT_RT paulmck
2020-06-30 16:45 ` Sebastian Andrzej Siewior
2020-06-30 18:35 ` Paul E. McKenney
2020-07-02 14:12 ` Sebastian Andrzej Siewior
2020-07-02 16:48 ` Paul E. McKenney
2020-07-02 20:19 ` Sebastian Andrzej Siewior
2020-07-06 21:06 ` Paul E. McKenney
2020-07-07 17:34 ` Uladzislau Rezki
2020-07-07 18:45 ` Joel Fernandes
2020-07-08 18:48 ` Uladzislau Rezki
2020-07-02 19:45 ` Uladzislau Rezki
2020-07-06 19:42 ` Joel Fernandes
2020-07-06 19:55 ` Uladzislau Rezki
2020-07-06 20:29 ` Joel Fernandes
2020-07-07 9:27 ` Sebastian Andrzej Siewior
2020-07-15 13:38 ` Uladzislau Rezki
2020-07-15 14:16 ` Sebastian Andrzej Siewior
2020-07-15 14:20 ` Uladzislau Rezki
2020-06-24 20:12 ` [PATCH tip/core/rcu 04/17] rcu/tree: Repeat the monitor if any free channel is busy paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 05/17] rcu/tree: Make debug_objects logic independent of rcu_head paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 06/17] rcu/tree: Simplify KFREE_BULK_MAX_ENTR macro paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 07/17] rcu/tree: Move kfree_rcu_cpu locking/unlocking to separate functions paulmck
2020-06-24 20:12 ` paulmck [this message]
2020-06-24 20:12 ` [PATCH tip/core/rcu 09/17] rcu/tree: cache specified number of objects paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 10/17] rcu/tree: Maintain separate array for vmalloc ptrs paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 11/17] rcu/tiny: support vmalloc in tiny-RCU paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 12/17] rcu: Rename *_kfree_callback/*_kfree_rcu_offset/kfree_call_* paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 13/17] mm/list_lru.c: Rename kvfree_rcu() to local variant paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 14/17] rcu: Introduce 2 arg kvfree_rcu() interface paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 15/17] rcu: Support reclaim for head-less object paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 16/17] rcu: Introduce single argument kvfree_rcu() interface paulmck
2020-06-24 20:12 ` [PATCH tip/core/rcu 17/17] lib/test_vmalloc.c: Add test cases for kvfree_rcu() paulmck
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