linux_dsm_epyc7002/arch
Frederic Weisbecker 280f06774a nohz: Separate out irq exit and idle loop dyntick logic
The tick_nohz_stop_sched_tick() function, which tries to delay
the next timer tick as long as possible, can be called from two
places:

- From the idle loop to start the dytick idle mode
- From interrupt exit if we have interrupted the dyntick
idle mode, so that we reprogram the next tick event in
case the irq changed some internal state that requires this
action.

There are only few minor differences between both that
are handled by that function, driven by the ts->inidle
cpu variable and the inidle parameter. The whole guarantees
that we only update the dyntick mode on irq exit if we actually
interrupted the dyntick idle mode, and that we enter in RCU extended
quiescent state from idle loop entry only.

Split this function into:

- tick_nohz_idle_enter(), which sets ts->inidle to 1, enters
dynticks idle mode unconditionally if it can, and enters into RCU
extended quiescent state.

- tick_nohz_irq_exit() which only updates the dynticks idle mode
when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called).

To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed
into tick_nohz_idle_exit().

This simplifies the code and micro-optimize the irq exit path (no need
for local_irq_save there). This also prepares for the split between
dynticks and rcu extended quiescent state logics. We'll need this split to
further fix illegal uses of RCU in extended quiescent states in the idle
loop.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: David Miller <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11 10:31:35 -08:00
..
alpha Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
arm nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
avr32 nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
blackfin nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
cris net: Fix references to deleted NET_ETHERNET Kconfig setting. 2011-11-09 19:26:53 -05:00
frv kgdb: follow rename pack_hex_byte() to hex_byte_pack() 2011-10-31 17:30:56 -07:00
h8300 Merge branch 'gpio/next' of git://git.secretlab.ca/git/linux-2.6 2011-10-29 07:27:45 -07:00
hexagon Hexagon: Add basic stacktrace functionality for Hexagon architecture. 2011-11-01 07:34:21 -07:00
ia64 Merge branch 'upstream/xen-settime' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen 2011-11-06 20:15:05 -08:00
m32r Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2011-11-06 18:54:53 -08:00
m68k m68k: Wire up process_vm_{read,write}v 2011-12-06 20:37:58 +01:00
microblaze nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
mips nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
mn10300 kgdb: follow rename pack_hex_byte() to hex_byte_pack() 2011-10-31 17:30:56 -07:00
openrisc nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
parisc parisc: Add export.h to files needing EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:31:00 -04:00
powerpc nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
s390 nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
score score: drop unused Kconfig symbols 2011-10-31 23:39:51 +01:00
sh nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
sparc nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
tile nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
um nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
unicore32 nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
x86 nohz: Separate out irq exit and idle loop dyntick logic 2011-12-11 10:31:35 -08:00
xtensa Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-26 17:15:03 +02:00
.gitignore
Kconfig Add Kconfig option ARCH_HAVE_NMI_SAFE_CMPXCHG 2011-08-03 11:12:37 -04:00