linux.git/Documentation/RCU, branch v4.19

rculist: Improve documentation for list_for_each_entry_from_rcu()

2018-07-12T22:39:25+00:00

Unfortunately the patch for adding list_for_each_entry_from_rcu()
wasn't the final patch after all review.  It is functionally
correct but the documentation was incomplete.

This patch adds this missing documentation which includes an update to
the documentation for list_for_each_entry_continue_rcu() to match the
documentation for the new list_for_each_entry_from_rcu(), and adds
list_for_each_entry_from_rcu() and the already existing
hlist_for_each_entry_from_rcu() to section 7 of whatisRCU.txt.

Reviewed-by: Paul E. McKenney 
Signed-off-by: NeilBrown 
Signed-off-by: Paul E. McKenney

doc: Update synchronize_rcu() definition in whatisRCU.txt

2018-07-12T22:39:23+00:00

The synchronize_rcu() definition based on RW-locks in whatisRCU.txt
does not meet the "Memory-Barrier Guarantees" in Requirements.html;
for example, the following SB-like test:

    P0:                      P1:

    WRITE_ONCE(x, 1);        WRITE_ONCE(y, 1);
    synchronize_rcu();       smp_mb();
    r0 = READ_ONCE(y);       r1 = READ_ONCE(x);

should not be allowed to reach the state "r0 = 0 AND r1 = 0", but
the current write_lock()+write_unlock() definition can not ensure
this.  This commit therefore inserts an smp_mb__after_spinlock()
in order to cause this synchronize_rcu() implementation to provide
this memory-barrier guarantee.

Suggested-by: Paul E. McKenney 
Signed-off-by: Andrea Parri 
Cc: Paul E. McKenney 
Cc: Josh Triplett 
Cc: Steven Rostedt 
Cc: Mathieu Desnoyers 
Cc: Lai Jiangshan 
Cc: Jonathan Corbet 
Signed-off-by: Paul E. McKenney

doc: Update RCU CPU stall-warning documentation

2018-07-12T22:38:51+00:00

Signed-off-by: Paul E. McKenney

doc: Update memory-ordering documentation for ->gp-seq

2018-07-12T22:38:51+00:00

Signed-off-by: Paul E. McKenney

doc: Update data-structure documentation for ->gp_seq

2018-07-12T22:38:49+00:00

Signed-off-by: Paul E. McKenney

doc: Ensure whatisRCU.txt actually says what RCU is

2018-05-15T17:28:12+00:00

It came to my attention that the file "whatisRCU.txt" does not
manage to actually ever spell out what is RCU.

This might not be an issue for a lot of people, but we have to
assume the consumers of these documents are starting from ground
zero; otherwise they'd not be reading the docs.

Signed-off-by: Paul Gortmaker 
Signed-off-by: Paul E. McKenney 
Tested-by: Nicholas Piggin

Merge branches 'cond_resched.2017.12.04a', 'dyntick.2017.11.28a', 'fixes.2017.12.11a', 'srbd.2017.12.05a' and 'torture.2017.12.11a' into HEAD

2017-12-11T17:21:58+00:00

cond_resched.2017.12.04a: Convert cond_resched_rcu_qs() to cond_resched()
dyntick.2017.11.28a: Make RCU dynticks handle interrupts from NMI
fixes.2017.12.11a: Miscellaneous fixes
srbd.2017.12.05a: Remove now-redundant smp_read_barrier_depends()
torture.2017.12.11a: Torture-testing update

doc: De-emphasize smp_read_barrier_depends

2017-12-05T19:57:53+00:00

This commit keeps only the historical and low-level discussion of
smp_read_barrier_depends().

Signed-off-by: Paul E. McKenney 
[ paulmck: Adjusted to allow for David Howells feedback on prior commit. ]

doc: Eliminate cond_resched_rcu_qs() in favor of cond_resched()

2017-12-04T18:28:59+00:00

Now that cond_resched() also provides RCU quiescent states when
needed, it can be used in place of cond_resched_rcu_qs().  This
commit therefore documents this change.

Signed-off-by: Paul E. McKenney

doc: Update dyntick-idle design documentation for NMI/irq consolidation

2017-11-28T23:51:22+00:00

Signed-off-by: Paul E. McKenney