Paul E. McKenney 9b2e4f1880 rcu: Track idleness independent of idle tasks ... Earlier versions of RCU used the scheduling-clock tick to detect idleness by checking for the idle task, but handled idleness differently for CONFIG_NO_HZ=y. But there are now a number of uses of RCU read-side critical sections in the idle task, for example, for tracing. A more fine-grained detection of idleness is therefore required. This commit presses the old dyntick-idle code into full-time service, so that rcu_idle_enter(), previously known as rcu_enter_nohz(), is always invoked at the beginning of an idle loop iteration. Similarly, rcu_idle_exit(), previously known as rcu_exit_nohz(), is always invoked at the end of an idle-loop iteration. This allows the idle task to use RCU everywhere except between consecutive rcu_idle_enter() and rcu_idle_exit() calls, in turn allowing architecture maintainers to specify exactly where in the idle loop that RCU may be used. Because some of the userspace upcall uses can result in what looks to RCU like half of an interrupt, it is not possible to expect that the irq_enter() and irq_exit() hooks will give exact counts. This patch therefore expands the ->dynticks_nesting counter to 64 bits and uses two separate bitfields to count process/idle transitions and interrupt entry/exit transitions. It is presumed that userspace upcalls do not happen in the idle loop or from usermode execution (though usermode might do a system call that results in an upcall). The counter is hard-reset on each process/idle transition, which avoids the interrupt entry/exit error from accumulating. Overflow is avoided by the 64-bitness of the ->dyntick_nesting counter. This commit also adds warnings if a non-idle task asks RCU to enter idle state (and these checks will need some adjustment before applying Frederic's OS-jitter patches (http://lkml.org/lkml/2011/10/7/246). In addition, validation of ->dynticks and ->dynticks_nesting is added. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>		2011-12-11 10:31:24 -08:00
..
ABI	block: Revert "[SCSI] genhd: add a new attribute "alias" in gendisk"	2011-11-10 09:03:55 +01:00
accounting	Documentation: update cgroupfs mount point	2011-06-15 21:52:50 -07:00
acpi	ACPI, APEI, EINJ Param support is disabled by default	2011-08-03 11:15:59 -04:00
aoe
arm	Merge branch 'next/deletion' of git+ssh://master.kernel.org/pub/scm/linux/kernel/git/arm/linux-arm-soc	2011-07-25 12:43:28 -07:00
auxdisplay
blackfin	doc: fix broken references	2011-09-27 18:08:04 +02:00
block	Documentation: drop as block elevator reference in switching-sched.txt	2011-11-04 12:01:48 -07:00
blockdev	cciss: auto engage SCSI mid layer at driver load time	2011-11-16 09:21:49 +01:00
cdrom	doc: fix broken references	2011-09-27 18:08:04 +02:00
cgroups	Documentation: Fix typo in freezer-subsystem.txt	2011-11-07 23:02:25 +01:00
connector
console
cpu-freq	Fix documentation and comment typo 'no_hz'	2011-08-08 18:55:59 +02:00
cpuidle
cris
crypto
development-process	doc: fix broken references	2011-09-27 18:08:04 +02:00
device-mapper	dm log userspace: fix comment hyphens	2011-10-31 20:21:22 +00:00
devicetree	of: Add Silicon Image vendor prefix	2011-11-29 08:24:20 -06:00
DocBook	Merge branch 'driver-core-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core	2011-11-21 20:36:26 -08:00
driver-model	docs/driver-model: Update device class docs	2011-08-24 16:01:24 -07:00
dvb	[media] update az6027 firmware URL	2011-10-14 10:29:45 -03:00
early-userspace
fault-injection	fault-injection: update documentation with the mmc module param	2011-10-26 16:32:13 -04:00
fb	udlfb: Enable fbcon access to framebuffer by default	2011-08-24 10:12:38 +00:00
filesystems	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2011-12-01 08:28:53 -08:00
firmware_class
frv	doc: fix broken references	2011-09-27 18:08:04 +02:00
hid	HID: Move hiddev.txt to the new Documentation/hid directory	2011-03-22 11:43:51 +01:00
hwmon	hwmon: (w83627ehf) Add support for the W83627UHG	2011-11-04 12:00:48 +01:00
i2c	i2c: Fix device name for 10-bit slave address	2011-11-23 11:33:07 +01:00
i2o	doc: i2o: fix typo 'Settting'	2011-06-07 16:06:01 +02:00
ia64	Fix common misspellings	2011-03-31 11:26:23 -03:00
ide
infiniband
input	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2011-10-27 08:44:20 +02:00
ioctl	ioctl: register LTTng ioctl	2011-09-12 11:50:56 -07:00
isdn	doc: fix wrong arch/i386 references	2011-06-13 13:43:05 +02:00
ja_JP	Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6	2011-07-25 23:06:24 -07:00
kbuild	doc: fix wrong arch/i386 references	2011-06-13 13:43:05 +02:00
kdump
ko_KR
laptops	Documentation: thinkpad-acpi grammo fixes	2011-11-04 12:01:47 -07:00
leds	Documentation: fix leds-class.txt duplicated word	2011-11-04 12:01:48 -07:00
m68k	Documentation: add pointer to name_to_dev_t for root= values	2011-08-03 14:25:21 -10:00
make
mips	Fix common misspellings	2011-03-31 11:26:23 -03:00
misc-devices	Fix common misspellings	2011-03-31 11:26:23 -03:00
mmc	mmc: documentation of mmc non-blocking request usage and design.	2011-07-21 10:34:52 -04:00
mn10300
mtd
namespaces
netlabel
networking	ipv4:correct description for tcp_max_syn_backlog	2011-12-06 13:02:28 -05:00
nfc
parisc
PCI	doc: fix broken references	2011-09-27 18:08:04 +02:00
pcmcia
power	PM / Sleep: Update documentation related to system wakeup	2011-11-28 22:14:45 +01:00
powerpc	Fix common misspellings	2011-03-31 11:26:23 -03:00
pps
prctl
pti	Kernel documentation for the PTI feature.	2011-05-13 16:31:00 -07:00
ptp	ptp: Added a brand new class driver for ptp clocks.	2011-05-23 13:01:00 -07:00
rapidio	RapidIO: documentation update	2011-11-02 16:07:02 -07:00
RCU	rcu: Track idleness independent of idle tasks	2011-12-11 10:31:24 -08:00
s390	[S390] remove tape block docu	2011-07-24 10:48:22 +02:00
scheduler	sched: Add documentation for bandwidth control	2011-08-14 12:03:58 +02:00
scsi	Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6	2011-10-28 16:44:18 -07:00
security	doc: fix broken references	2011-09-27 18:08:04 +02:00
serial	RS485: fix inconsistencies in the meaning of some variables	2011-11-15 12:13:44 -08:00
sh
sound	Merge branch 'fix/asoc' into for-linus	2011-12-06 13:22:28 +01:00
sparc
spi	doc: fix broken references	2011-09-27 18:08:04 +02:00
sysctl	kernel/sysctl.c: add cap_last_cap to /proc/sys/kernel	2011-10-31 17:30:53 -07:00
target	[SCSI] tcm_mod_builder.py: Fix generated *_drop_nodeacl() handler	2011-03-23 11:36:45 -05:00
telephony	Fix common misspellings	2011-03-31 11:26:23 -03:00
thermal
timers	doc: fix broken references	2011-09-27 18:08:04 +02:00
trace	mm: change isolate mode from #define to bitwise type	2011-10-31 17:30:44 -07:00
usb	USB: linux-cdc-acm.inf: add support for the acm_ms gadget	2011-11-29 09:59:29 +09:00
vDSO	Document the vDSO and add a reference parser	2011-07-14 17:57:09 -07:00
video4linux	[media] gspca - zc3xx: New webcam 03f0:1b07 HP Premium Starter Cam	2011-09-23 23:31:12 -03:00
virtual	Merge branch 'for-linus' of git://github.com/richardweinberger/linux	2011-11-02 09:45:39 -07:00
vm	Merge branches 'slab/next' and 'slub/partial' into slab/for-linus	2011-10-26 18:09:12 +03:00
w1	Fix common misspellings	2011-03-31 11:26:23 -03:00
watchdog	Documentation: watchdog: add guide how to convert drivers to new framework	2011-11-05 21:25:16 +01:00
wimax
x86	x86-64, doc: Remove int 0xcc from entry_64.S documentation	2011-08-16 08:04:08 -07:00
zh_CN	remove the messy code file Documentation/zh_CN/SubmitChecklist	2011-09-26 16:18:41 -07:00
.gitignore
00-INDEX	Documentation: add Ramoops usage description	2011-08-13 18:34:03 -07:00
applying-patches.txt
atomic_ops.txt	Documentation/atomic_ops.txt: avoid volatile in sample code	2011-05-26 17:12:34 -07:00
bad_memory.txt
basic_profiling.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
cachetlb.txt	mm: convert mm->cpu_vm_cpumask into cpumask_var_t	2011-05-25 08:39:21 -07:00
Changes	Documentation/Changes: remove some really obsolete text	2011-07-11 16:48:38 -07:00
circular-buffers.txt
coccinelle.txt
CodingStyle	Documentation: update CodingStyle use of braces	2011-11-04 12:01:47 -07:00
cpu-hotplug.txt	Fix common misspellings	2011-03-31 11:26:23 -03:00
cpu-load.txt
cputopology.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt	Fix common misspellings	2011-03-31 11:26:23 -03:00
devices.txt
DMA-API-HOWTO.txt	Documentation/DMA-API-HOWTO.txt: fix misleading example	2011-07-26 16:49:45 -07:00
DMA-API.txt	include/linux/dma-mapping.h: add dma_zalloc_coherent()	2011-11-02 16:07:02 -07:00
DMA-attributes.txt
DMA-ISA-LPC.txt
dmaengine.txt	Improve slave/cyclic DMA engine documentation	2011-07-27 20:33:48 +05:30
dontdiff	Documentation: update dontdiff file	2011-05-23 15:14:11 -07:00
dynamic-debug-howto.txt	Merge branch 'docs-next' of git://git.lwn.net/linux-2.6	2011-03-27 19:46:59 -07:00
edac.txt	Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6	2011-04-07 11:14:49 -07:00
eisa.txt	Fix common misspellings	2011-03-31 11:26:23 -03:00
email-clients.txt	Documentation: email-clients: Add better Thunderbird information	2011-08-13 18:34:03 -07:00
feature-removal-schedule.txt	sysctl: make CONFIG_SYSCTL_SYSCALL default to n	2011-11-02 16:07:02 -07:00
flexible-arrays.txt	flex_array: flex_array_prealloc takes a number of elements, not an end	2011-04-28 16:12:47 -04:00
futex-requeue-pi.txt
gcov.txt
gpio.txt
highuid.txt
HOWTO	Documentation: update LXR web link	2011-05-23 15:14:11 -07:00
hw_random.txt
hwspinlock.txt	hwspinlock/core: register a bank of hwspinlocks in a single API call	2011-09-21 19:45:34 +03:00
init.txt
initrd.txt
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt	Documentation/iostats.txt: bit-size reference etc.	2011-03-23 20:44:18 +01:00
IPMI.txt
IRQ-affinity.txt	bitmap, irq: add smp_affinity_list interface to /proc/irq	2011-05-25 08:39:45 -07:00
IRQ.txt
irqflags-tracing.txt	Fix common misspellings	2011-03-31 11:26:23 -03:00
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt
kernel-docs.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
kernel-parameters.txt	Merge branch 'iommu/fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu	2011-12-09 08:08:14 -08:00
kmemcheck.txt
kmemleak.txt	Documentation: update kmemleak supported archs	2011-06-15 21:52:50 -07:00
kobject.txt
kprobes.txt
kref.txt	kref: Fix typo in kref documentation	2011-03-07 13:20:05 -08:00
ldm.txt
local_ops.txt
lockdep-design.txt	lockdep: Update documentation for lock-class leak detection	2011-12-11 10:31:23 -08:00
lockstat.txt	Documentation: Add statistics about nested locks	2011-05-28 17:03:29 +02:00
logo.gif
logo.txt
magic-number.txt	doc: fix wrong arch/i386 references	2011-06-13 13:43:05 +02:00
Makefile
ManagementStyle
mca.txt	doc: fix wrong arch/i386 references	2011-06-13 13:43:05 +02:00
md.txt	md: update documentation for md/rdev/state sysfs interface	2011-07-28 11:31:48 +10:00
media-framework.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
memory-barriers.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
memory-hotplug.txt
memory.txt
mono.txt
mutex-design.txt
nmi_watchdog.txt
nommu-mmap.txt
numastat.txt
oops-tracing.txt	module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree	2011-11-07 07:54:42 +10:30
padata.txt
parport-lowlevel.txt
parport.txt
pi-futex.txt
pinctrl.txt	drivers: create a pin control subsystem	2011-10-13 12:49:17 +02:00
pnp.txt
preempt-locking.txt
printk-formats.txt	Documentation: update printk-formats.txt	2011-06-15 21:52:50 -07:00
prio_tree.txt
ramoops.txt	Documentation: add Ramoops usage description	2011-08-13 18:34:03 -07:00
rbtree.txt	Documentation: Update augmented rbtree documentation	2011-07-24 10:03:05 -07:00
rfkill.txt	doc: fix broken references	2011-09-27 18:08:04 +02:00
robust-futex-ABI.txt
robust-futexes.txt
rt-mutex-design.txt
rt-mutex.txt
rtc.txt	RTC: Fix up rtc.txt documentation to reflect changes to generic rtc layer	2011-03-09 11:25:10 -08:00
SAK.txt
SecurityBugs	Fix common misspellings	2011-03-31 11:26:23 -03:00
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
SM501.txt
sparse.txt
spinlocks.txt	Documentation/spinlocks.txt: Remove reference to sti()/cli()	2011-07-11 12:45:04 -07:00
stable_api_nonsense.txt	doc: stable_api_nonsense.txt: fix paragraph to make more sense.	2011-03-30 12:02:05 +02:00
stable_kernel_rules.txt	Update email address for stable patch submission	2011-10-18 13:58:59 -07:00
SubmitChecklist	Documentation/SubmitChecklist: add RCU debug config options	2011-07-25 20:57:17 -07:00
SubmittingDrivers	Documentation: SubmittingDrivers: fix Linus's git tree URL	2011-08-13 18:34:03 -07:00
SubmittingPatches	Documentation: fix spelling error in SubmittingPatches	2011-08-13 18:34:02 -07:00
svga.txt
sysfs-rules.txt
sysrq.txt
unaligned-memory-access.txt
unicode.txt
unshare.txt
VGA-softcursor.txt
vgaarbiter.txt	Documentation: fix vgaarbiter.txt typos etc.	2011-05-23 15:14:11 -07:00
video-output.txt
volatile-considered-harmful.txt
workqueue.txt	workqueue: Document debugging tricks	2011-03-31 13:40:42 +02:00
xz.txt
zorro.txt