linux-toradex.git/kernel/rcutree_trace.c, branch v3.7

Merge remote-tracking branch 'tip/smp/hotplug' into next.2012.09.25b

2012-09-25T17:01:45+00:00

The conflicts between kernel/rcutree.h and kernel/rcutree_plugin.h
were due to adjacent insertions and deletions, which were resolved
by simply accepting the changes on both branches.

Merge branches 'bigrt.2012.09.23a', 'doctorture.2012.09.23a', 'fixes.2012.09.23a', 'hotplug.2012.09.23a' and 'idlechop.2012.09.23a' into HEAD

2012-09-25T03:02:22+00:00

bigrt.2012.09.23a contains additional commits to reduce scheduling latency
	from RCU on huge systems (many hundrends or thousands of CPUs).

doctorture.2012.09.23a contains documentation changes and rcutorture fixes.

fixes.2012.09.23a contains miscellaneous fixes.

hotplug.2012.09.23a contains CPU-hotplug-related changes.

idle.2012.09.23a fixes architectures for which RCU no longer considered
	the idle loop to be a quiescent state due to earlier
	adaptive-dynticks changes.  Affected architectures are alpha,
	cris, frv, h8300, m32r, m68k, mn10300, parisc, score, xtensa,
	and ia64.

rcu: Remove _rcu_barrier() dependency on __stop_machine()

2012-09-23T14:43:55+00:00

Currently, _rcu_barrier() relies on preempt_disable() to prevent
any CPU from going offline, which in turn depends on CPU hotplug's
use of __stop_machine().

This patch therefore makes _rcu_barrier() use get_online_cpus() to
block CPU-hotplug operations.  This has the added benefit of removing
the need for _rcu_barrier() to adopt callbacks:  Because CPU-hotplug
operations are excluded, there can be no callbacks to adopt.  This
commit simplifies the code accordingly.

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

rcu: Simplify quiescent-state detection

2012-09-23T14:41:56+00:00

The current quiescent-state detection algorithm is needlessly
complex.  It records the grace-period number corresponding to
the quiescent state at the time of the quiescent state, which
works, but it seems better to simply erase any record of previous
quiescent states at the time that the CPU notices the new grace
period.  This has the further advantage of removing another piece
of RCU for which lockless reasoning is required.

Therefore, this commit makes this change.

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

rcu: Adjust debugfs tracing for kthread-based quiescent-state forcing

2012-09-23T14:41:54+00:00

Moving quiescent-state forcing into a kthread dispenses with the need
for the ->n_rp_need_fqs field, so this commit removes it.

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

rcu: Use smp_hotplug_thread facility for RCUs per-CPU kthread

2012-08-13T15:01:08+00:00

Bring RCU into the new-age CPU-hotplug fold by modifying RCU's per-CPU
kthread code to use the new smp_hotplug_thread facility.

[ tglx: Adapted it to use callbacks and to the simplified rcu yield ]

Signed-off-by: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Srivatsa S. Bhat 
Cc: Rusty Russell 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/r/20120716103948.673354828@linutronix.de
Signed-off-by: Thomas Gleixner

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

2012-07-06T13:01:49+00:00

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: Use for_each_rcu_flavor() in TREE_RCU tracing

2012-07-02T19:33:24+00:00

This commit applies the new for_each_rcu_flavor() macro to the
kernel/rcutree_trace.c file.

Signed-off-by: Paul E. McKenney

rcu: Add rcu_barrier() statistics to debugfs tracing

2012-07-02T19:33:23+00:00

This commit adds an rcubarrier file to RCU's debugfs statistical tracing
directory, providing diagnostic information on rcu_barrier().

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

rcu: Control RCU_FANOUT_LEAF from boot-time parameter

2012-07-02T19:33:20+00:00

Although making RCU_FANOUT_LEAF a kernel configuration parameter rather
than a fixed constant makes it easier for people to decrease cache-miss
overhead for large systems, it is of little help for people who must
run a single pre-built kernel binary.

This commit therefore allows the value of RCU_FANOUT_LEAF to be
increased (but not decreased!) via a boot-time parameter named
rcutree.rcu_fanout_leaf.

Reported-by: Mike Galbraith 
Signed-off-by: Paul E. McKenney