v7 version of RCU lazy patches based on rcu/next branch. To facilitate easier merge, I dropped tracing and other patches and just implemented the new changes. I will post the tracing patches later along with rcutop as I need to add new tracepoints that Frederic suggested. Main recent changes: 1. rcu_barrier() wake up only for lazy bypass list. 2. Make all call_rcu() default-lazy and add call_rcu_flush() API. 3. Take care of some callers using call_rcu_flush() API. 4. Several refactorings suggested by Paul/Frederic. 5. New call_rcu() to call_rcu_flush() conversions by Joel/Vlad/Paul. I am seeing good performance and power with these patches on real ChromeOS x86 asymmetric hardware. Earlier cover letter with lots of details is here: https://lore.kernel.org/all/20220901221720.1105021-1-joel@xxxxxxxxxxxxxxxxx/ List of recent changes: [ Frederic Weisbec: Program the lazy timer only if WAKE_NOT, since other deferral levels wake much earlier so for those it is not needed. ] [ Frederic Weisbec: Use flush flags to keep bypass API code clean. ] [ Frederic Weisbec: Make rcu_barrier() wake up only if main list empty. ] [ Frederic Weisbec: Remove extra 'else if' branch in rcu_nocb_try_bypass(). ] [ Joel: Fix issue where I was not resetting lazy_len after moving it to rdp ] [ Paul/Thomas/Joel: Make call_rcu() default lazy so users don't mess up. ] [ Paul/Frederic : Cosmetic changes, split out wakeup of nocb thread. ] [ Vlad/Joel : More call_rcu -> flush conversions ] Frederic Weisbecker (1): rcu: Wake up nocb gp thread on rcu_barrier_entrain() Joel Fernandes (Google) (7): rcu: Make call_rcu() lazy to save power rcu: Refactor code a bit in rcu_nocb_do_flush_bypass() rcuscale: Add laziness and kfree tests percpu-refcount: Use call_rcu_flush() for atomic switch rcu/sync: Use call_rcu_flush() instead of call_rcu rcu/rcuscale: Use call_rcu_flush() for async reader test rcu/rcutorture: Use call_rcu_flush() where needed Uladzislau Rezki (2): scsi/scsi_error: Use call_rcu_flush() instead of call_rcu() workqueue: Make queue_rcu_work() use call_rcu_flush() Vineeth Pillai (1): rcu: shrinker for lazy rcu drivers/scsi/scsi_error.c | 2 +- include/linux/rcupdate.h | 7 ++ kernel/rcu/Kconfig | 8 ++ kernel/rcu/rcu.h | 8 ++ kernel/rcu/rcuscale.c | 67 +++++++++++- kernel/rcu/rcutorture.c | 16 +-- kernel/rcu/sync.c | 2 +- kernel/rcu/tiny.c | 2 +- kernel/rcu/tree.c | 140 +++++++++++++++++-------- kernel/rcu/tree.h | 12 ++- kernel/rcu/tree_exp.h | 2 +- kernel/rcu/tree_nocb.h | 213 ++++++++++++++++++++++++++++++++------ kernel/workqueue.c | 2 +- lib/percpu-refcount.c | 3 +- 14 files changed, 388 insertions(+), 96 deletions(-) -- 2.38.0.rc1.362.ged0d419d3c-goog
