Hello!
This is version 3 of a patch series creating a new notrace variant of
SRCU-fast and introducing it to the __DECLARE_TRACE() in place of the
current preemption disabling. This change enable preemption of BPF
programs attached to tracepoints, as is required for runtime use of BPF
in real-time systems.
1. Move rcu_is_watching() checks to srcu_read_{,un}lock_fast().
2. Add srcu_read_lock_fast_notrace() and
srcu_read_unlock_fast_notrace().
3. Add guards for notrace variants of SRCU-fast readers.
4. Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast.
Changes since v2:
o Posting standalone as opposed to a reply.
https://lore.kernel.org/all/3cecf6c9-b2ee-4f34-9d1b-ca4cfb8e56a7@paulmck-laptop/
Changes since RFC version:
o RFC patch 6/4 has been pulled into the shared RCU tree:
e88c632a8698 ("srcu: Add guards for SRCU-fast readers")
o RFC patch 5/4 (which removed the now-unnecessary special boot-time
avoidance of SRCU) has been folded into patch 4/4 shown above,
as suggested by Steven Rostedt.
https://lore.kernel.org/all/bb20a575-235b-499e-aa1d-70fe9e2c7617@paulmck-laptop/
Thanx, Paul
------------------------------------------------------------------------
b/include/linux/srcu.h | 4 ++++
b/include/linux/srcutree.h | 2 --
b/include/linux/tracepoint.h | 6 ++++--
b/kernel/tracepoint.c | 21 ++++++++++++++++++++-
include/linux/srcu.h | 30 ++++++++++++++++++++++++++++++
5 files changed, 58 insertions(+), 5 deletions(-)
