user/sven/linux.git/kernel/rcutiny_plugin.h, branch v3.11.2

rcu: Shrink TINY_RCU by reworking CPU-stall ifdefs

2013-06-10T20:45:53Z

TINY_RCU's reset_cpu_stall_ticks() and check_cpu_stalls() functions are defined unconditionally, and are empty functions if CONFIG_RCU_TRACE is disabled (which in turns disables detection of RCU CPU stalls). This commit saves a few lines of source code by defining these functions only if CONFIG_RCU_TRACE=y. Signed-off-by: Paul E. McKenney

rcu: Consolidate rcutiny_plugin.h ifdefs

2013-06-10T20:45:52Z

This commit rearranges code in order to allow ifdefs to be consolidated in kernel/rcutiny_plugin.h, simplifying the code. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Remove check_cpu_stall_preempt()

2013-06-10T20:45:51Z

With the removal of CONFIG_TINY_PREEMPT_RCU, check_cpu_stall_preempt() is now an empty function. This commit therefore eliminates it by inlining it. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Simplify RCU_TINY RCU callback invocation

2013-06-10T20:45:51Z

TINY_PREEMPT_RCU could use a kthread to handle RCU callback invocation, which required an API to abstract kthread vs. softirq invocation. Now that TINY_PREEMPT_RCU is no longer with us, this commit retires this API in favor of direct use of the relevant softirq primitives. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Remove rcu_preempt_process_callbacks()

2013-06-10T20:45:50Z

With the removal of CONFIG_TINY_PREEMPT_RCU, rcu_preempt_process_callbacks() is now an empty function. This commit therefore eliminates it by inlining it. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Remove rcu_preempt_remove_callbacks()

2013-06-10T20:45:50Z

With the removal of CONFIG_TINY_PREEMPT_RCU, rcu_preempt_remove_callbacks() is now an empty function. This commit therefore eliminates it by inlining it. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Remove rcu_preempt_check_callbacks()

2013-06-10T20:45:50Z

With the removal of CONFIG_TINY_PREEMPT_RCU, rcu_preempt_check_callbacks() is now an empty function. This commit therefore eliminates it by inlining it. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Remove show_tiny_preempt_stats()

2013-06-10T20:45:49Z

With the removal of CONFIG_TINY_PREEMPT_RCU, show_tiny_preempt_stats() is now an empty function. This commit therefore eliminates it by inlining it. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Remove TINY_PREEMPT_RCU

2013-06-10T20:45:49Z

TINY_PREEMPT_RCU adds significant code and complexity, but does not offer commensurate benefits. People currently using TINY_PREEMPT_RCU can get much better memory footprint with TINY_RCU, or, if they really need preemptible RCU, they can use TREE_PREEMPT_RCU with a relatively minor degradation in memory footprint. Please note that this move has been widely publicized on LKML (https://lkml.org/lkml/2012/11/12/545) and on LWN (http://lwn.net/Articles/541037/). This commit therefore removes TINY_PREEMPT_RCU. Signed-off-by: Paul E. McKenney [ paulmck: Updated to eliminate #else in rcutiny.h as suggested by Josh ] Reviewed-by: Josh Triplett

rcu: Provide RCU CPU stall warnings for tiny RCU

2013-01-29T06:06:21Z

Tiny RCU has historically omitted RCU CPU stall warnings in order to reduce memory requirements, however, lack of these warnings caused Thomas Gleixner some debugging pain recently. Therefore, this commit adds RCU CPU stall warnings to tiny RCU if RCU_TRACE=y. This keeps the memory footprint small, while still enabling CPU stall warnings in kernels built to enable them. Updated to include Josh Triplett's suggested use of RCU_STALL_COMMON config variable to simplify #if expressions. Reported-by: Thomas Gleixner Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett