linux/kernel/rcutiny.c, branch v3.12

rcu: Add const annotation to char * for RCU tracepoints and functions

2013-07-29T21:07:49Z

All the RCU tracepoints and functions that reference char pointers do so with just 'char *' even though they do not modify the contents of the string itself. This will cause warnings if a const char * is used in one of these functions. The RCU tracepoints store the pointer to the string to refer back to them when the trace output is displayed. As this can be minutes, hours or even days later, those strings had better be constant. This change also opens the door to allow the RCU tracepoint strings and their addresses to be exported so that userspace tracing tools can translate the contents of the pointers of the RCU tracepoints. Signed-off-by: Steven Rostedt

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: 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

Merge branches 'doctorture.2013.01.29a', 'fixes.2013.01.26a', 'tagcb.2013.01.24a' and 'tiny.2013.01.29b' into HEAD

2013-01-29T06:25:21Z

doctorture.2013.01.11a: Changes to rcutorture and to RCU documentation. fixes.2013.01.26a: Miscellaneous fixes. tagcb.2013.01.24a: Tag RCU callbacks with grace-period number to simplify callback advancement. tiny.2013.01.29b: Enhancements to uniprocessor handling in tiny RCU.

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

rcu: Make rcu_is_cpu_rrupt_from_idle helper functions static

2013-01-08T22:15:25Z

Both rcutiny and rcutree define a helper function named rcu_is_cpu_rrupt_from_idle(), each used exactly once, later in the same file. This commit therefore declares these helper functions static. Signed-off-by: Josh Triplett Signed-off-by: Paul E. McKenney

rcu: Fix TINY_RCU rcu_is_cpu_rrupt_from_idle check

2012-11-13T22:08:34Z

The rcu_is_cpu_rrupt_from_idle() needs to allow for one interrupt level from the idle loop, but TINY_RCU checks for a call from the idle loop itself. This commit fixes this issue. Reported-by: Josh Triplett Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney