linux-stable.git/kernel/rcutorture.c, branch v3.3.6

rcu: Add missing __cpuinit annotation in rcutorture code

2012-01-16T17:44:05+00:00

"rcu: Add rcutorture CPU-hotplug capability" adds cpu hotplug operations
to the rcutorture code but produces a false positive warning about section
mismatches:

WARNING: vmlinux.o(.text+0x1e420c): Section mismatch in reference from the
	 function rcu_torture_onoff() to the function .cpuinit.text:cpu_up()
	 The function rcu_torture_onoff() references
	 the function __cpuinit cpu_up().
	 This is often because rcu_torture_onoff lacks a __cpuinit
	 annotation or the annotation of cpu_up is wrong.

This commit therefore adds a __cpuinit annotation so the warning goes away.

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

rcu: Make rcutorture bool parameters really bool (core code)

2012-01-16T17:43:56+00:00

module_param(bool) used to counter-intuitively take an int.  In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy
trick.

It's time to remove the int/unsigned int option.  For this version
it'll simply give a warning, but it'll break next kernel version.
This commit makes this change to rcutorture.

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

rcu: Add rcutorture tests for srcu_read_lock_raw()

2011-12-11T18:32:21+00:00

This commit adds simple rcutorture tests for srcu_read_lock_raw() and
srcu_read_unlock_raw().  It does not test doing srcu_read_lock_raw()
in an exception handler and releasing it in the corresponding process
context.

Signed-off-by: Paul E. McKenney

rcu: Make rcutorture test for hotpluggability before offlining CPUs

2011-12-11T18:32:21+00:00

The rcutorture test now can automatically exercise CPU hotplug and
collect success statistics, which can be correlated with other rcutorture
activity.  This permits rcutorture to completely exercise RCU regardless
of what sort of userspace and filesystem layout is in use.  Unfortunately,
rcutorture is happy to attempt to offline CPUs that cannot be offlined,
for example, CPU 0 in both the x86 and ARM architectures.  Although this
allows rcutorture testing to proceed normally, it confounds attempts at
error analysis due to the resulting flood of spurious CPU-hotplug errors.

Therefore, this commit uses the new cpu_is_hotpluggable() function to
avoid attempting to offline CPUs that are not hotpluggable, which in
turn avoids spurious CPU-hotplug errors.

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

rcu: Add rcutorture CPU-hotplug capability

2011-12-11T18:31:56+00:00

Running CPU-hotplug operations concurrently with rcutorture has
historically been a good way to find bugs in both RCU and CPU hotplug.
This commit therefore adds an rcutorture module parameter called
"onoff_interval" that causes a randomly selected CPU-hotplug operation to
be executed at the specified interval, in seconds.  The default value of
"onoff_interval" is zero, which disables rcutorture-instigated CPU-hotplug
operations.

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

rcu: Control rcutorture startup from kernel boot parameters

2011-12-11T18:31:47+00:00

Currently, if rcutorture is built into the kernel, it must be manually
started or started from an init script.  This is inconvenient for
automated KVM testing, where it is good to be able to fully control
rcutorture execution from the kernel parameters.  This patch therefore
adds a module parameter named "rcutorture_runnable" that defaults
to zero ("don't start automatically"), but which can be set to one
to cause rcutorture to start up immediately during boot.

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

rcu: Add rcutorture system-shutdown capability

2011-12-11T18:31:46+00:00

Although it is easy to run rcutorture tests under KVM, there is currently
no nice way to run such a test for a fixed time period, collect all of
the rcutorture data, and then shut the system down cleanly.  This commit
therefore adds an rcutorture module parameter named "shutdown_secs" that
specified the run duration in seconds, after which rcutorture terminates
the test and powers the system down.  The default value for "shutdown_secs"
is zero, which disables shutdown.

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

rcu: Add failure tracing to rcutorture

2011-12-11T18:31:26+00:00

Trace the rcutorture RCU accesses and dump the trace buffer when the
first failure is detected.

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

rcu: Make rcu_torture_boost() exit loops at end of test

2011-09-29T04:38:46+00:00

One of the loops in rcu_torture_boost() fails to check kthread_should_stop(),
and thus might be slowing or even stopping completion of rcutorture tests
at rmmod time.  This commit adds the kthread_should_stop() check to the
offending loop.

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

rcu: Make rcu_torture_fqs() exit loops at end of test

2011-09-29T04:38:44+00:00

The rcu_torture_fqs() function can prevent the rcutorture tests from
completing, resulting in a hang.  This commit therefore ensures that
rcu_torture_fqs() will exit its inner loops at the end of the test,
and also applies the newish ULONG_CMP_LT() macro to time comparisons.

Signed-off-by: Paul E. McKenney