linux-stable.git/kernel/rcutiny_plugin.h, branch v3.3.6

rcu: Apply ACCESS_ONCE() to rcu_boost() return value

2011-12-11T18:33:19+00:00

Both TINY_RCU's and TREE_RCU's implementations of rcu_boost() access
the ->boost_tasks and ->exp_tasks fields without preventing concurrent
changes to these fields.  This commit therefore applies ACCESS_ONCE in
order to prevent compiler mischief.

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

rcu: Augment rcu_batch_end tracing for idle and callback state

2011-12-11T18:32:22+00:00

The current rcu_batch_end event trace records only the name of the RCU
flavor and the total number of callbacks that remain queued on the
current CPU.  This is insufficient for testing and tuning the new
dyntick-idle RCU_FAST_NO_HZ code, so this commit adds idle state along
with whether or not any of the callbacks that were ready to invoke
at the beginning of rcu_do_batch() are still queued.

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

kernel: fix up module header handling in rcutiny files

2011-10-31T13:20:13+00:00

The file rcutiny.c does not need moduleparam.h header, as
there are no modparams in this file.

However rcutiny_plugin.h does define a module_init() and
a module_exit() and it uses the various MODULE_ macros, so
it really does need module.h included.

Signed-off-by: Paul Gortmaker

rcu: Make TINY_RCU also use softirq for RCU_BOOST=n

2011-09-29T04:38:20+00:00

This patch #ifdefs TINY_RCU kthreads out of the kernel unless RCU_BOOST=y,
thus eliminating context-switch overhead if RCU priority boosting has
not been configured.

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

rcu: Put names into TINY_RCU structures under RCU_TRACE

2011-09-29T04:38:14+00:00

In order to allow event tracing to distinguish between flavors of
RCU, we need those names in the relevant RCU data structures.  TINY_RCU
has avoided them for memory-footprint reasons, so add them only if
CONFIG_RCU_TRACE=y.

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

rcu: Abstract common code for RCU grace-period-wait primitives

2011-09-29T04:36:42+00:00

Pull the code that waits for an RCU grace period into a single function,
which is then called by synchronize_rcu() and friends in the case of
TREE_RCU and TREE_PREEMPT_RCU, and from rcu_barrier() and friends in
the case of TINY_RCU and TINY_PREEMPT_RCU.

Signed-off-by: Paul E. McKenney

rcu: Converge TINY_RCU expedited and normal boosting

2011-05-06T06:16:58+00:00

This applies a trick from TREE_RCU boosting to TINY_RCU, eliminating
code and adding comments.  The key point is that it is possible for
the booster thread itself to work out whether there is a normal or
expedited boost required based solely on local information.  There
is therefore no need for boost initiation to know or care what type
of boosting is required.  In addition, when boosting is complete for
a given grace period, then by definition there cannot be any more
boosting for that grace period.  This allows eliminating yet more
state and statistics.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Paul E. McKenney 
Reviewed-by: Josh Triplett

rcu: remove useless ->boosted_this_gp field

2011-05-06T06:16:58+00:00

The ->boosted_this_gp field is a holdover from an earlier design that
was to carry out multiple boost operations in parallel.  It is not required
by the current design, which boosts one task at a time.

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

rcu: code cleanups in TINY_RCU priority boosting.

2011-05-06T06:16:58+00:00

Extraneous semicolon, bad comment, and fold INIT_LIST_HEAD() into
list_del() to get list_del_init().

Signed-off-by: Paul E. McKenney 
Signed-off-by: Paul E. McKenney 
Reviewed-by: Josh Triplett

rcu: call __rcu_read_unlock() in exit_rcu for tiny RCU

2011-03-04T16:05:08+00:00

Using __rcu_read_lock() in place of rcu_read_lock() leaves any debug
state as it really should be, namely with the lock still held.

Signed-off-by: Lai Jiangshan 
Signed-off-by: Paul E. McKenney