linux.git/Documentation/RCU, branch v4.14

doc: Set down RCU's scheduling-clock-interrupt needs

2017-08-17T14:31:14+00:00

This commit documents the situations in which RCU needs the
scheduling-clock interrupt to be enabled, along with the consequences
of failing to meet RCU's needs in this area.

Signed-off-by: Paul E. McKenney

doc: No longer allowed to use rcu_dereference on non-pointers

2017-08-17T14:29:58+00:00

There are too many ways for the compiler to optimize (that is, break)
dependencies carried via integer values, so it is now permissible to
carry dependencies only via pointers.  This commit catches up some of
the documentation on this point.

Signed-off-by: Paul E. McKenney

doc: Update RCU documentation

2017-08-17T14:29:48+00:00

Signed-off-by: Paul E. McKenney

rcu: Remove debugfs tracing

2017-06-09T01:52:43+00:00

RCU's debugfs tracing used to be the only reasonable low-level debug
information available, but ftrace and event tracing has since surpassed
the RCU debugfs level of usefulness.  This commit therefore removes
RCU's debugfs tracing.

Signed-off-by: Paul E. McKenney

rcu: Remove SPARSE_RCU_POINTER Kconfig option

2017-06-09T01:52:41+00:00

The sparse-based checking for non-RCU accesses to RCU-protected pointers
has been around for a very long time, and it is now the only type of
sparse-based checking that is optional.  This commit therefore makes
it unconditional.

Reported-by: Ingo Molnar 
Signed-off-by: Paul E. McKenney 
Cc: Fengguang Wu

rcu: Remove nohz_full full-system-idle state machine

2017-06-09T01:52:39+00:00

The NO_HZ_FULL_SYSIDLE full-system-idle capability was added in 2013
by commit 0edd1b1784cb ("nohz_full: Add full-system-idle state machine"),
but has not been used.  This commit therefore removes it.

If it turns out to be needed later, this commit can always be reverted.

Signed-off-by: Paul E. McKenney 
Cc: Frederic Weisbecker 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Acked-by: Linus Torvalds

doc: Take tail recursion into account in RCU requirements

2017-06-08T15:25:34+00:00

This commit classifies tail recursion as an alternative way to write
a loop, with similar limitations.

Signed-off-by: Paul E. McKenney

srcu: Document auto-expediting requirement

2017-06-08T15:25:33+00:00

This commit documents the auto-expediting requirement satisfied by
commits 2da4b2a7fd8d ("srcu: Expedite first synchronize_srcu() when idle")
and 22607d66bbc3 ("srcu: Specify auto-expedite holdoff time").

Signed-off-by: Paul E. McKenney

Merge branches 'doc.2017.04.12a', 'fixes.2017.04.19a' and 'srcu.2017.04.21a' into HEAD

2017-04-21T13:00:13+00:00

doc.2017.04.12a: Documentation updates
fixes.2017.04.19a: Miscellaneous fixes
srcu.2017.04.21a: Parallelize SRCU callback handling

mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU

2017-04-18T18:42:36+00:00

A group of Linux kernel hackers reported chasing a bug that resulted
from their assumption that SLAB_DESTROY_BY_RCU provided an existence
guarantee, that is, that no block from such a slab would be reallocated
during an RCU read-side critical section.  Of course, that is not the
case.  Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire
slab of blocks.

However, there is a phrase for this, namely "type safety".  This commit
therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order
to avoid future instances of this sort of confusion.

Signed-off-by: Paul E. McKenney 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Andrew Morton 
Cc: 
Acked-by: Johannes Weiner 
Acked-by: Vlastimil Babka 
[ paulmck: Add comments mentioning the old name, as requested by Eric
  Dumazet, in order to help people familiar with the old name find
  the new one. ]
Acked-by: David Rientjes