From 4fea6ef0b219d66b8a901fea1744745a1ed2f79b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 9 Jan 2019 14:48:09 -0800 Subject: doc: Remove obsolete RCU update functions from RCU documentation Now that synchronize_rcu_bh, synchronize_rcu_bh_expedited, call_rcu_bh, rcu_barrier_bh, synchronize_sched, synchronize_sched_expedited, call_rcu_sched, rcu_barrier_sched, get_state_synchronize_sched, and cond_synchronize_sched are obsolete, let's remove them from the documentation aside from a small historical section. Signed-off-by: Paul E. McKenney --- Documentation/RCU/Design/Data-Structures/Data-Structures.html | 3 +-- .../RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html | 4 +++- .../RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html | 5 ++--- 3 files changed, 6 insertions(+), 6 deletions(-) (limited to 'Documentation/RCU/Design') diff --git a/Documentation/RCU/Design/Data-Structures/Data-Structures.html b/Documentation/RCU/Design/Data-Structures/Data-Structures.html index 18f179807563..c30c1957c7e6 100644 --- a/Documentation/RCU/Design/Data-Structures/Data-Structures.html +++ b/Documentation/RCU/Design/Data-Structures/Data-Structures.html @@ -155,8 +155,7 @@ keeping lock contention under control at all tree levels regardless of the level of loading on the system.

RCU updaters wait for normal grace periods by registering -RCU callbacks, either directly via call_rcu() and -friends (namely call_rcu_bh() and call_rcu_sched()), +RCU callbacks, either directly via call_rcu() or indirectly via synchronize_rcu() and friends. RCU callbacks are represented by rcu_head structures, which are queued on rcu_data structures while they are diff --git a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html index 19e7a5fb6b73..57300db4b5ff 100644 --- a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html +++ b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html @@ -56,6 +56,7 @@ sections. RCU-preempt Expedited Grace Periods

+CONFIG_PREEMPT=y kernels implement RCU-preempt. The overall flow of the handling of a given CPU by an RCU-preempt expedited grace period is shown in the following diagram: @@ -139,6 +140,7 @@ or offline, among other things. RCU-sched Expedited Grace Periods

+CONFIG_PREEMPT=n kernels implement RCU-sched. The overall flow of the handling of a given CPU by an RCU-sched expedited grace period is shown in the following diagram: @@ -146,7 +148,7 @@ expedited grace period is shown in the following diagram:

As with RCU-preempt, RCU-sched's -synchronize_sched_expedited() ignores offline and +synchronize_rcu_expedited() ignores offline and idle CPUs, again because they are in remotely detectable quiescent states. However, because the diff --git a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html index 8d21af02b1f0..c64f8d26609f 100644 --- a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html +++ b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html @@ -34,12 +34,11 @@ Similarly, any code that happens before the beginning of a given RCU grace period is guaranteed to see the effects of all accesses following the end of that grace period that are within RCU read-side critical sections. -

This guarantee is particularly pervasive for synchronize_sched(), -for which RCU-sched read-side critical sections include any region +

Note well that RCU-sched read-side critical sections include any region of code for which preemption is disabled. Given that each individual machine instruction can be thought of as an extremely small region of preemption-disabled code, one can think of -synchronize_sched() as smp_mb() on steroids. +synchronize_rcu() as smp_mb() on steroids.

RCU updaters use this guarantee by splitting their updates into two phases, one of which is executed before the grace period and -- cgit v1.2.3