linux/kernel/rcutorture.c, branch v3.8

Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD

2012-11-16T17:59:58Z

urgent.2012.10.27a: Fix for RCU user-mode transition (already in -tip). doc.2012.11.08a: Documentation updates, most notably codifying the memory-barrier guarantees inherent to grace periods. fixes.2012.11.13a: Miscellaneous fixes. srcu.2012.10.27a: Allow statically allocated and initialized srcu_struct structures (courtesy of Lai Jiangshan). stall.2012.11.13a: Add more diagnostic information to RCU CPU stall warnings, also decrease from 60 seconds to 21 seconds. hotplug.2012.11.08a: Minor updates to CPU hotplug handling. tracing.2012.11.08a: Improved debugfs tracing, courtesy of Michael Wang. idle.2012.10.24a: Updates to RCU idle/adaptive-idle handling, including a boot parameter that maps normal grace periods to expedited. Resolved conflict in kernel/rcutree.c due to side-by-side change.

rcu: Add new rcutorture module parameters to start/end test messages

2012-11-13T22:08:22Z

Several new rcutorture module parameters have been added, but are not printed to the console at the beginning and end of tests, which makes it difficult to reproduce a prior test. This commit therefore adds these new module parameters to the list printed at the beginning and the end of the tests. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney

rcutorture: Use DEFINE_STATIC_SRCU()

2012-10-27T22:39:20Z

Use DEFINE_STATIC_SRCU() to simplify the rcutorture.c SRCU test code. Signed-off-by: Lai Jiangshan Reviewed-by: Josh Triplett Signed-off-by: Paul E. McKenney

rcu: Make rcutorture give diagnostics if CPU offline fails

2012-10-23T21:46:47Z

This commit causes rcutorture to print the errno if cpu_down() fails when the rcutorture "verbose" module parameter is specified. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney

rcu: Prevent initialization race in rcutorture kthreads

2012-09-23T14:42:23Z

When you do something like "t = kthread_run(...)", it is possible that the kthread will start running before the assignment to "t" happens. If the child kthread expects to find a pointer to its task_struct in "t", it will then be fatally disappointed. This commit therefore switches such cases to kthread_create() followed by wake_up_process(), guaranteeing that the assignment happens before the child kthread starts running. Reported-by: Fengguang Wu Signed-off-by: Paul E. McKenney

rcu: Switch rcutorture to pr_alert() and friends

2012-09-23T14:42:23Z

Drop a few characters by switching kernel/rcutorture.c from "printk(KERN_ALERT" to "pr_alert(". Signed-off-by: Paul E. McKenney

rcu: Track CPU-hotplug duration statistics

2012-09-23T14:42:22Z

Many rcutorture runs include CPU-hotplug operations in their stress testing. This commit accumulates statistics on the durations of these operations in deference to the recent concern about the overhead and latency of these operations. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Update rcutorture defaults

2012-09-23T14:42:22Z

A number of new features have been added to rcutorture over the years, but the defaults have not been updated to include them. This commit therefore turns on a couple of them that have proven helpful and trustworthy, namely periodic progress reports and testing of NO_HZ. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Fix broken strings in RCU's source code.

2012-07-06T13:01:49Z

Although the C language allows you to break strings across lines, doing this makes it hard for people to find the Linux kernel code corresponding to a given console message. This commit therefore fixes broken strings throughout RCU's source code. Suggested-by: Josh Triplett Suggested-by: Ingo Molnar Signed-off-by: Paul E. McKenney

rcu: Fix code-style issues involving "else"

2012-07-06T13:01:48Z

The Linux kernel coding style says that single-statement blocks should omit curly braces unless the other leg of the "if" statement has multiple statements, in which case the curly braces should be included. This commit fixes RCU's violations of this rule. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett