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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2018-12-11 12:12:38 +0100
committerPaul E. McKenney <paulmck@linux.ibm.com>2019-01-25 15:36:42 -0800
commite81baf4cb19a9b428ba477fd0423f81672a58817 (patch)
treefd518df0bf3f31968c4541ff488f0c727cc1b2b2 /include/linux
parentc8ca1aa774b20f182733d1661f3b6aa3105338e7 (diff)
srcu: Remove srcu_queue_delayed_work_on()
srcu_queue_delayed_work_on() disables preemption (and therefore CPU hotplug in RCU's case) and then checks based on its own accounting if a CPU is online. If the CPU is online it uses queue_delayed_work_on() otherwise it fallbacks to queue_delayed_work(). The problem here is that queue_work() on -RT does not work with disabled preemption. queue_work_on() works also on an offlined CPU. queue_delayed_work_on() has the problem that it is possible to program a timer on an offlined CPU. This timer will fire once the CPU is online again. But until then, the timer remains programmed and nothing will happen. Add a local timer which will fire (as requested per delay) on the local CPU and then enqueue the work on the specific CPU. RCUtorture testing with SRCU-P for 24h showed no problems. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/srcutree.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
index 6f292bd3e7db..0faa978c9880 100644
--- a/include/linux/srcutree.h
+++ b/include/linux/srcutree.h
@@ -45,7 +45,8 @@ struct srcu_data {
unsigned long srcu_gp_seq_needed; /* Furthest future GP needed. */
unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */
bool srcu_cblist_invoking; /* Invoking these CBs? */
- struct delayed_work work; /* Context for CB invoking. */
+ struct timer_list delay_work; /* Delay for CB invoking */
+ struct work_struct work; /* Context for CB invoking. */
struct rcu_head srcu_barrier_head; /* For srcu_barrier() use. */
struct srcu_node *mynode; /* Leaf srcu_node. */
unsigned long grpmask; /* Mask for leaf srcu_node */