Hello!
This series reduces memory footprint (RCU callbacks posted by no-CBs CPUs)
by causing the no-CBs CPUs to use the existing ->cblist segmented callback
list. This allows these callbacks to take advantage of RCU grace periods
that were started by something other than the corresponding rcuog kthread:
1. Use separate flag to indicate disabled ->cblist.
2. Use separate flag to indicate offloaded ->cblist.
3. Add checks for offloaded callback processing.
4. Make rcutree_migrate_callbacks() start at leaf rcu_node structure.
5. Check for deferred nocb wakeups before nohz_full early exit.
6. Remove deferred wakeup checks for extended quiescent states.
7. Allow lockless use of rcu_segcblist_restempty().
8. Allow lockless use of rcu_segcblist_empty().
9. Leave ->cblist enabled for no-CBs CPUs.
10. Use rcu_segcblist for no-CBs CPUs.
11. Remove obsolete nocb_head and nocb_tail fields.
12. Remove obsolete nocb_q_count and nocb_q_count_lazy fields.
13. Remove obsolete nocb_cb_tail and nocb_cb_head fields.
14. Remove obsolete nocb_gp_head and nocb_gp_tail fields.
15. Use build-time no-CBs check in rcu_do_batch().
16. Use build-time no-CBs check in rcu_core().
17. Use build-time no-CBs check in rcu_pending().
18. Suppress uninitialized false-positive in nocb_gp_wait().
Thanx, Paul
------------------------------------------------------------------------
include/linux/rcu_segcblist.h | 2
include/trace/events/rcu.h | 1
kernel/rcu/rcu_segcblist.c | 64 +++-
kernel/rcu/rcu_segcblist.h | 16 -
kernel/rcu/tree.c | 188 +++++++------
kernel/rcu/tree.h | 29 --
kernel/rcu/tree_plugin.h | 588 ++++++++++++++----------------------------
7 files changed, 374 insertions(+), 514 deletions(-)
