diff options
| author | Ingo Molnar <mingo@kernel.org> | 2017-01-16 07:45:44 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-01-16 07:45:44 +0100 |
| commit | 3e4f7a4956e54143f7fc15c636158ad4166d219d (patch) | |
| tree | c286358c42c47328a12f523878e8cc9fa022f9f9 /include | |
| parent | f4d3935e4f4884ba80561db5549394afb8eef8f7 (diff) | |
| parent | 52d7e48b86fc108e45a656d8e53e4237993c481d (diff) | |
Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into rcu/urgent
Pull an urgent RCU fix from Paul E. McKenney:
"This series contains a pair of commits that permit RCU synchronous grace
periods (synchronize_rcu() and friends) to work correctly throughout boot.
This eliminates the current "dead time" starting when the scheduler spawns
its first taks and ending when the last of RCU's kthreads is spawned
(this last happens during early_initcall() time). Although RCU's
synchronous grace periods have long been documented as not working
during this time, prior to 4.9, the expedited grace periods worked by
accident, and some ACPI code came to rely on this unintentional behavior.
(Note that this unintentional behavior was -not- reliable. For example,
failures from ACPI could occur on !SMP systems and on systems booting
with the rcu_normal kernel boot parameter.)
Either way, there is a bug that needs fixing, and the 4.9 switch of RCU's
expedited grace periods to workqueues could be considered to have caused
a regression. This series therefore makes RCU's expedited grace periods
operate correctly throughout the boot process. This has been demonstrated
to fix the problems ACPI was encountering, and has the added longer-term
benefit of simplifying RCU's behavior."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/rcupdate.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 321f9ed552a9..01f71e1d2e94 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -444,6 +444,10 @@ bool __rcu_is_watching(void); #error "Unknown RCU implementation specified to kernel configuration" #endif +#define RCU_SCHEDULER_INACTIVE 0 +#define RCU_SCHEDULER_INIT 1 +#define RCU_SCHEDULER_RUNNING 2 + /* * init_rcu_head_on_stack()/destroy_rcu_head_on_stack() are needed for dynamic * initialization and destruction of rcu_head on the stack. rcu_head structures |