Hello! This series contains updates to RCU expedited grace periods, most notably providing milliseconds-scale soft real-time response from synchronize_rcu_expedited(). This is also the first time in almost 30 years of RCU that someone other than me has pushed for a reduction in the RCU CPU stall-warning timeout, in this case by more than three orders of magnitude from 21 seconds to 20 milliseconds. This tighter timeout applies only to expedited grace periods. 1. Introduce CONFIG_RCU_EXP_CPU_STALL_TIMEOUT, courtesy of Uladzislau Rezki. 2. Move expedited grace period (GP) work to RT kthread_worker, courtesy of Kalesh Singh. Thanx, Paul ------------------------------------------------------------------------ b/Documentation/RCU/stallwarn.rst | 18 ++ b/Documentation/admin-guide/kernel-parameters.txt | 9 + b/kernel/rcu/Kconfig | 14 ++ b/kernel/rcu/Kconfig.debug | 13 + b/kernel/rcu/rcu.h | 2 b/kernel/rcu/tree.c | 51 +++++++ b/kernel/rcu/tree.h | 5 b/kernel/rcu/tree_exp.h | 4 b/kernel/rcu/tree_stall.h | 26 +++ b/kernel/rcu/update.c | 2 kernel/rcu/rcu.h | 5 kernel/rcu/tree_exp.h | 147 +++++++++++++++++----- 12 files changed, 260 insertions(+), 36 deletions(-)
