user/sven/linux.git/kernel/rcutiny_plugin.h, branch v3.0.50

rcu: Converge TINY_RCU expedited and normal boosting

2011-05-06T06:16:58Z

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

2011-05-06T06:16:58Z

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.

2011-05-06T06:16:58Z

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

2011-03-04T16:05:08Z

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

rcu: Distinguish between boosting and boosted

2010-11-30T06:01:56Z

RCU priority boosting's tracing did not distinguish between ongoing boosting and completion of boosting. This commit therefore adds this capability. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney

rcu: add tracing for TINY_RCU and TINY_PREEMPT_RCU

2010-11-30T06:01:55Z

Add tracing for the tiny RCU implementations, including statistics on boosting in the case of TINY_PREEMPT_RCU and RCU_BOOST. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney

rcu: priority boosting for TINY_PREEMPT_RCU

2010-11-30T06:01:54Z

Add priority boosting, but only for TINY_PREEMPT_RCU. This is enabled by the default-off RCU_BOOST kernel parameter. The priority to which to boost preempted RCU readers is controlled by the RCU_BOOST_PRIO kernel parameter (defaulting to real-time priority 1) and the time to wait before boosting the readers blocking a given grace period is controlled by the RCU_BOOST_DELAY kernel parameter (defaulting to 500 milliseconds). Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney

rcu: move TINY_RCU from softirq to kthread

2010-11-17T23:45:09Z

If RCU priority boosting is to be meaningful, callback invocation must be boosted in addition to preempted RCU readers. Otherwise, in presence of CPU real-time threads, the grace period ends, but the callbacks don't get invoked. If the callbacks don't get invoked, the associated memory doesn't get freed, so the system is still subject to OOM. But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit moves the callback invocations to a kthread, which can be boosted easily. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney

rcu: performance fixes to TINY_PREEMPT_RCU callback checking

2010-08-27T17:51:17Z

This commit tightens up checks in rcu_preempt_check_callbacks() to avoid unnecessary special handling at rcu_read_unlock() time. Signed-off-by: Paul E. McKenney

rcu: repair code-duplication FIXMEs

2010-08-20T16:00:13Z

Combine the duplicate definitions of ULONG_CMP_GE(), ULONG_CMP_LT(), and rcu_preempt_depth() into include/linux/rcupdate.h. Signed-off-by: Paul E. McKenney