From: Neeraj Upadhyay <neeraj.upadhyay@xxxxxxxxxx> Architectures for which all deep-idle and entry-exit functions are marked noinstr, synchronize_rcu_tasks_rude() is not required. However, disabling synchronize_rcu_tasks_rude() for such architectures require RCU-tasks to pay attention to idle tasks until they enter the context where RCU is not watching. In addition, NMI context need to track RCU-tasks entry/exit for NO_HZ_FULL CPUs. This series adds changes for both of these requirements. The series is available in git tree at: https://git.kernel.org/pub/scm/linux/kernel/git/neeraj.upadhyay/linux-rcu.git/log/?h=rcu.tasks.idle Changes since v1: https://lore.kernel.org/lkml/20240807163506.434885-1-neeraj.upadhyay@xxxxxxxxxx/ - Split into multiple patches (Paul) - Various restructuring updates (Frederic) - Fix race with early boot code (Frederic) - Check RCU watching state for idle injection tasks. - Include patch to turn synchronize_rcu_tasks_rude() into noop for architectures with CONFIG_ARCH_WANTS_NO_INSTR enabled. Neeraj Upadhyay (9): rcu: Change rdp arg to cpu number for rcu_watching_snap_stopped_since() rcu: Make some rcu_watching_* functions global rcu/tasks: Move holdout checks for idle task to a separate function rcu/tasks: Create rcu_idle_task_is_holdout() definition for !SMP rcu/tasks: Consider idle tasks not running on CPU as non-holdouts rcu/tasks: Check RCU watching state for holdout idle tasks rcu/tasks: Check RCU watching state for holdout idle injection tasks rcu/tasks: Make RCU-tasks pay attention to idle tasks context_tracking: Invoke RCU-tasks enter/exit for NMI context Paul E. McKenney (1): rcu: Allow short-circuiting of synchronize_rcu_tasks_rude() .../RCU/Design/Requirements/Requirements.rst | 12 +- kernel/context_tracking.c | 11 +- kernel/rcu/rcu.h | 4 + kernel/rcu/tasks.h | 148 ++++++++++++++---- kernel/rcu/tree.c | 16 +- kernel/rcu/tree_exp.h | 2 +- 6 files changed, 140 insertions(+), 53 deletions(-) -- 2.40.1
