linux.git/Documentation/RCU, branch v2.6.27

rcu: make rcutorture even more vicious: invoke RCU readers from irq handlers (timers)

2008-06-26T07:24:33+00:00

This patch allows torturing RCU from irq handlers (timers, in this case).
A new module parameter irqreader enables such additional torturing,
and is enabled by default.  Variants of RCU that do not tolerate readers
being called from irq handlers (e.g., SRCU) ignore irqreader.

Signed-off-by: Paul E. McKenney 
Cc: josh@freedesktop.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: dino@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: torvalds@linux-foundation.org
Cc: vegard.nossum@gmail.com
Cc: adobriyan@gmail.com
Cc: oleg@tv-sign.ru
Cc: bunk@kernel.org
Cc: rjw@sisk.pl
Signed-off-by: Ingo Molnar

rcu: make rcutorture more vicious: reinstate boot-time testing

2008-06-19T09:22:15+00:00

This patch re-institutes the ability to build rcutorture directly into
the Linux kernel.  The reason that this capability was removed was that
this could result in your kernel being pretty much useless, as rcutorture
would be running starting from early boot.  This problem has been avoided
by (1) making rcutorture run only three seconds of every six by default,
(2) adding a CONFIG_RCU_TORTURE_TEST_RUNNABLE that permits rcutorture
to be quiesced at boot time, and (3) adding a sysctl in /proc named
/proc/sys/kernel/rcutorture_runnable that permits rcutorture to be
quiesced and unquiesced when built into the kernel.

Please note that this /proc file is -not- available when rcutorture
is built as a module.  Please also note that to get the earlier
take-no-prisoners behavior, you must use the boot command line to set
rcutorture's "stutter" parameter to zero.

The rcutorture quiescing mechanism is currently quite crude: loops
in each rcutorture process that poll a global variable once per tick.
Suggestions for improvement are welcome.  The default action will
be to reduce the polling rate to a few times per second.

Signed-off-by: Paul E. McKenney 
Suggested-by: Ingo Molnar 
Signed-off-by: Ingo Molnar

rcu: make rcutorture more vicious: add stutter feature

2008-06-18T13:06:56+00:00

This patch takes a step towards making rcutorture more brutal by allowing
the test to be automatically periodically paused, with the default being
to run the test for five seconds then pause for five seconds and repeat.
This behavior can be controlled using a new "stutter" module parameter, so
that "stutter=0" gives the old default behavior of running continuously.

Starting and stopping rcutorture more heavily stresses RCU's interaction
with the scheduler, as well as exercising more paths through the
grace-period detection code.

Note that the default to "shuffle_interval" has also been adjusted from
5 seconds to 3 seconds to provide varying overlap with the "stutter"
interval.

I am still unable to provoke the failures that Alexey has been seeing,
even with this patch, but will be doing a few additional things to beef
up rcutorture.

Suggested-by: Ingo Molnar 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Ingo Molnar

sched: 1Q08 RCU doc update, add call_rcu_sched()

2008-05-19T08:01:37+00:00

Long-delayed update to the RCU documentation, including adding the new
call_rcu_sched() and rcu_barrier_sched() APIs.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Ingo Molnar 
Signed-off-by: Thomas Gleixner

remove final fastcall users

2008-02-14T00:21:18+00:00

fastcall always expands to empty, remove it.

Signed-off-by: Harvey Harrison 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Preempt-RCU: update RCU Documentation.

2008-01-25T20:08:25+00:00

This patch updates the RCU documentation to reflect preemptible RCU as
well as recent publications.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Gautham R Shenoy 
Reviewed-by: Steven Rostedt 
Signed-off-by: Ingo Molnar

Add Documentation/RCU/00-Index

2007-10-17T15:43:07+00:00

Add Documentation/RCU/00-INDEX

Signed-off-by: Rob Landley 
Acked-by: Paul E. McKenney 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Document the fact that RCU callbacks can run in parallel

2007-07-16T16:05:47+00:00

Add an item to the RCU documentation checklist noting that RCU callbacks
can run in parallel.

Signed-off-by: Paul E. McKenney 
Cc: Steven Rostedt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] rcu: add sched torture type to rcutorture

2006-10-04T14:55:31+00:00

Implement torture testing for the "sched" variant of RCU, which uses
preempt_disable, preempt_enable, and synchronize_sched.

Signed-off-by: Josh Triplett 
Acked-by: Paul E. McKenney 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] rcu: add rcu_bh_sync torture type to rcutorture

2006-10-04T14:55:31+00:00

Use the newly-generic synchronous deferred free function to implement torture
testing for rcu_bh using synchronize_rcu_bh rather than the asynchronous
call_rcu_bh.

Signed-off-by: Josh Triplett 
Acked-by: Paul E. McKenney 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds