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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-17 01:34:00 +08:00
linux-next/Documentation/RCU
Frederic Weisbecker 3451d0243c nohz: Rename CONFIG_NO_HZ to CONFIG_NO_HZ_COMMON
We are planning to convert the dynticks Kconfig options layout
into a choice menu. The user must be able to easily pick
any of the following implementations: constant periodic tick,
idle dynticks, full dynticks.

As this implies a mutual exclusion, the two dynticks implementions
need to converge on the selection of a common Kconfig option in order
to ease the sharing of a common infrastructure.

It would thus seem pretty natural to reuse CONFIG_NO_HZ to
that end. It already implements all the idle dynticks code
and the full dynticks depends on all that code for now.
So ideally the choice menu would propose CONFIG_NO_HZ_IDLE and
CONFIG_NO_HZ_EXTENDED then both would select CONFIG_NO_HZ.

On the other hand we want to stay backward compatible: if
CONFIG_NO_HZ is set in an older config file, we want to
enable CONFIG_NO_HZ_IDLE by default.

But we can't afford both at the same time or we run into
a circular dependency:

1) CONFIG_NO_HZ_IDLE and CONFIG_NO_HZ_EXTENDED both select
   CONFIG_NO_HZ
2) If CONFIG_NO_HZ is set, we default to CONFIG_NO_HZ_IDLE

We might be able to support that from Kconfig/Kbuild but it
may not be wise to introduce such a confusing behaviour.

So to solve this, create a new CONFIG_NO_HZ_COMMON option
which gathers the common code between idle and full dynticks
(that common code for now is simply the idle dynticks code)
and select it from their referring Kconfig.

Then we'll later create CONFIG_NO_HZ_IDLE and map CONFIG_NO_HZ
to it for backward compatibility.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-03 13:56:03 +02:00
..
00-INDEX rcu: Remove conditional compilation for RCU CPU stall warnings 2011-05-05 23:16:54 -07:00
arrayRCU.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
checklist.txt rcu: Remove list_for_each_continue_rcu() 2012-11-13 14:08:21 -08:00
listRCU.txt rcu: Update docs to include kfree_rcu() 2012-11-08 11:44:25 -08:00
lockdep-splat.txt rcu: Document interpretation of RCU-lockdep splats 2011-09-28 21:38:28 -07:00
lockdep.txt rcu: Update documentation for additional RCU lockdep functions 2011-09-28 21:38:25 -07:00
NMI-RCU.txt rcu: Fix RCU's NMI documentation 2011-09-28 21:36:44 -07:00
rcu.txt rcu: Add documentation for raw SRCU read-side primitives 2011-12-11 10:31:41 -08:00
rcubarrier.txt rcu: Update documentation to cover call_srcu() and srcu_barrier(). 2012-07-02 12:34:03 -07:00
rculist_nulls.txt netfilter: nf_conntrack: nf_conntrack_alloc() fixes 2009-07-16 14:03:40 +02:00
rcuref.txt rcu: Document alternative RCU/reference-count algorithms 2012-11-08 11:44:38 -08:00
RTFP.txt rcu: Correct the name of a reference in list of RCU papers 2012-10-23 14:44:47 -07:00
stallwarn.txt nohz: Rename CONFIG_NO_HZ to CONFIG_NO_HZ_COMMON 2013-04-03 13:56:03 +02:00
torture.txt rcu: Update documentation to cover call_srcu() and srcu_barrier(). 2012-07-02 12:34:03 -07:00
trace.txt rcu: Add documentation for the new rcuexp debugfs trace file 2012-11-16 09:55:31 -08:00
UP.txt rcu: Add synchronize_sched_expedited() rcutorture doc + updates 2009-07-03 10:02:29 +02:00
whatisRCU.txt 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 2012-11-16 09:59:58 -08:00