From: Lai Jiangshan <jiangshan.ljs@antgroup.com>

X86 can access percpu data in a single instruction.

Use per-cpu rcu preempt count and make it able to be inlined.

patch 1-7: prepare
patch 8-10: implement PCPU_RCU_PREEMPT_COUNT

Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <frederic@kernel.org>

Lai Jiangshan (10):
  lib: Use rcu_preempt_depth() to replace current->rcu_read_lock_nesting
  rcu: Move rcu_preempt_depth_set() to rcupdate.h
  rcu: Reorder tree_exp.h after tree_plugin.h
  rcu: Add macros set_rcu_preempt_special() and
    clear_rcu_preempt_special()
  rcu: Make rcu_read_unlock_special() global
  rcu: Rename marco __LINUX_RCU_H to __KERNEL_RCU_H
  sched/core: Add rcu_preempt_switch()
  rcu: Implement PCPU_RCU_PREEMPT_COUNT framework
  x86/rcu: Add rcu_preempt_count
  x86/rcu: Add THUNK rcu_read_unlock_special_thunk

 arch/x86/Kconfig                   |   1 +
 arch/x86/entry/thunk_64.S          |   5 ++
 arch/x86/include/asm/current.h     |   3 +
 arch/x86/include/asm/rcu_preempt.h | 109 +++++++++++++++++++++++++++++
 arch/x86/kernel/cpu/common.c       |   7 +-
 include/linux/rcupdate.h           |  36 ++++++++++
 kernel/rcu/Kconfig                 |   8 +++
 kernel/rcu/rcu.h                   |  15 +++-
 kernel/rcu/tree.c                  |   2 +-
 kernel/rcu/tree_exp.h              |   2 +-
 kernel/rcu/tree_plugin.h           |  41 +++++++----
 kernel/sched/core.c                |   2 +
 lib/locking-selftest.c             |   6 +-
 13 files changed, 211 insertions(+), 26 deletions(-)
 create mode 100644 arch/x86/include/asm/rcu_preempt.h

-- 
2.19.1.6.gb485710b