From: Paul E. McKenney paulmck@kernel.org
[ Upstream commit ef1ef3d47677dc191b88650a9f7f91413452cc1b ]
The rcu_scale_shutdown() and kfree_scale_shutdown() kthreads/functions use wait_event() to wait for the rcuscale test to complete. However, each updater thread in such a test waits for at least 100 grace periods. If each grace period takes more than 1.2 seconds, which is long, but not insanely so, this can trigger the hung-task timeout.
This commit therefore replaces those wait_event() calls with calls to wait_event_idle(), which do not trigger the hung-task timeout.
Reported-by: kernel test robot yujie.liu@intel.com Reported-by: Liam Howlett liam.howlett@oracle.com Signed-off-by: Paul E. McKenney paulmck@kernel.org Tested-by: Yujie Liu yujie.liu@intel.com Signed-off-by: Boqun Feng boqun.feng@gmail.com Stable-dep-of: 23fc8df26dea ("rcu/rcuscale: Stop kfree_scale_thread thread(s) after unloading rcuscale") Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/rcu/rcuscale.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 3ef02d4a81085..de4d4e3844bb1 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -630,8 +630,7 @@ static int compute_real(int n) static int rcu_scale_shutdown(void *arg) { - wait_event(shutdown_wq, - atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters); + wait_event_idle(shutdown_wq, atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters); smp_mb(); /* Wake before output. */ rcu_scale_cleanup(); kernel_power_off(); @@ -757,8 +756,8 @@ kfree_scale_cleanup(void) static int kfree_scale_shutdown(void *arg) { - wait_event(shutdown_wq, - atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads); + wait_event_idle(shutdown_wq, + atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads);
smp_mb(); /* Wake before output. */