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| author |   Joel Fernandes (Google) <joel@joelfernandes.org> | 2019-08-15 22:59:14 -0400 |
|---|---|---|
| committer |   Paul E. McKenney <paulmck@kernel.org> | 2019-10-30 08:34:35 -0700 |
| commit | 05ef9e9eb3dade21413680f41eb0170778e8ae2b (patch) | |
| tree | 6e57e0d53beeec1aeda061fe7e53b05ad18e9d37 /kernel | |
| parent | workqueue: Convert for_each_wq to use built-in list check (diff) | |
| download | linux-dev-05ef9e9eb3dade21413680f41eb0170778e8ae2b.tar.xz linux-dev-05ef9e9eb3dade21413680f41eb0170778e8ae2b.zip | |
rcu: Ensure that ->rcu_urgent_qs is set before resched IPI
The RCU-specific resched_cpu() function sends a resched IPI to the
specified CPU, which can be used to force the tick on for a given
nohz_full CPU. This is needed when this nohz_full CPU is looping in the
kernel while blocking the current grace period. However, for the tick
to actually be forced on in all cases, that CPU's rcu_data structure's
->rcu_urgent_qs flag must be set beforehand. This commit therefore
causes rcu_implicit_dynticks_qs() to set this flag prior to invoking
resched_cpu() on a holdout nohz_full CPU.
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcu/tree.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 81105141b6a8..0d83b1944e19 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1073,6 +1073,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) if (tick_nohz_full_cpu(rdp->cpu) && time_after(jiffies, READ_ONCE(rdp->last_fqs_resched) + jtsq * 3)) { + WRITE_ONCE(*ruqp, true); resched_cpu(rdp->cpu); WRITE_ONCE(rdp->last_fqs_resched, jiffies); } |