linux/kernel/rcu
Pranith Kumar 11ed7f934c rcu: Make nocb leader kthreads process pending callbacks after spawning
The nocb callbacks generated before the nocb kthreads are spawned are
enqueued in the nocb queue for later processing. Commit fbce7497ee ("rcu:
Parallelize and economize NOCB kthread wakeups") introduced nocb leader kthreads
which checked the nocb_leader_wake flag to see if there were any such pending
callbacks. A case was reported in which newly spawned leader kthreads were not
processing the pending callbacks as this flag was not set, which led to a boot
hang.

The following commit ensures that the newly spawned nocb kthreads process the
pending callbacks by allowing the kthreads to run immediately after spawning
instead of waiting. This is done by inverting the logic of nocb_leader_wake
tests to nocb_leader_sleep which allows us to use the default initialization of
this flag to 0 to let the kthreads run.

Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Link: http://www.spinics.net/lists/kernel/msg1802899.html
[ paulmck: Backported to v3.17-rc2. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Amit Shah <amit.shah@redhat.com>
2014-08-28 05:59:59 -07:00
..
Makefile rcutorture: Abstract rcu_torture_random() 2014-02-23 09:00:58 -08:00
rcu.h rcu: Fix __rcu_reclaim() to use true/false for bool 2014-07-09 09:15:32 -07:00
rcutorture.c Josh has moved 2014-07-30 17:16:13 -07:00
srcu.c rcu: Eliminate read-modify-write ACCESS_ONCE() calls 2014-07-09 09:14:49 -07:00
tiny.c rcu: Ensure kernel/rcu/rcu.h can be sourced/used stand-alone 2014-02-26 06:35:18 -08:00
tiny_plugin.h rcu: Protect uses of ->jiffies_stall with ACCESS_ONCE() 2014-04-29 08:44:41 -07:00
tree.c rcu: Remove CONFIG_PROVE_RCU_DELAY 2014-07-09 09:15:31 -07:00
tree.h rcu: Make nocb leader kthreads process pending callbacks after spawning 2014-08-28 05:59:59 -07:00
tree_plugin.h rcu: Make nocb leader kthreads process pending callbacks after spawning 2014-08-28 05:59:59 -07:00
tree_trace.c rcu: Stop tracking FSF's postal address 2014-02-17 15:01:37 -08:00
update.c rcu: Remove CONFIG_PROVE_RCU_DELAY 2014-07-09 09:15:31 -07:00