linux/Documentation
Chris Metcalf fe4ba3c343 watchdog: add watchdog_cpumask sysctl to assist nohz
Change the default behavior of watchdog so it only runs on the
housekeeping cores when nohz_full is enabled at build and boot time.
Allow modifying the set of cores the watchdog is currently running on
with a new kernel.watchdog_cpumask sysctl.

In the current system, the watchdog subsystem runs a periodic timer that
schedules the watchdog kthread to run.  However, nohz_full cores are
designed to allow userspace application code running on those cores to
have 100% access to the CPU.  So the watchdog system prevents the
nohz_full application code from being able to run the way it wants to,
thus the motivation to suppress the watchdog on nohz_full cores, which
this patchset provides by default.

However, if we disable the watchdog globally, then the housekeeping
cores can't benefit from the watchdog functionality.  So we allow
disabling it only on some cores.  See Documentation/lockup-watchdogs.txt
for more information.

[jhubbard@nvidia.com: fix a watchdog crash in some configurations]
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:40 -07:00
..
ABI powerpc updates for 4.2 2015-06-24 08:46:32 -07:00
accounting
acpi ACPI: Constify ACPI device IDs in documentation 2015-06-19 01:14:15 +02:00
aoe
arm ARM: SoC multiplatform code changes for v4.1 2015-04-22 09:20:15 -07:00
arm64 arm64: use fixmap region for permanent FDT mapping 2015-06-02 16:31:33 +01:00
auxdisplay
backlight
blackfin Documentation: blackfin: Makefile: Typo building issue 2015-04-11 15:19:31 +02:00
block Documentation: Remove mentioning of block barriers 2015-03-20 07:41:56 -06:00
blockdev Merge branch 'for-4.1/drivers' of git://git.kernel.dk/linux-block 2015-04-16 22:05:27 -04:00
bus-devices
cdrom
cgroups The documentation tree update for 4.1. Numerous fixes, the overdue removal 2015-04-18 11:10:49 -04:00
cma cma: debug: document new debugfs interface 2015-04-14 16:49:00 -07:00
connector
console
cpu-freq Documentation: cpufreq: delete duplicate description of sysfs interface 'scaling_driver' 2015-05-05 23:23:25 +02:00
cpuidle
cris
crypto crypto: doc - AEAD / RNG AF_ALG interface 2015-03-09 21:06:18 +11:00
development-process Documentation: remove outdated references to the linux-next wiki 2014-10-28 09:06:11 -04:00
device-mapper dm crypt: update URLs to new cryptsetup project page 2015-04-15 12:10:24 -04:00
devicetree powerpc updates for 4.2 2015-06-24 08:46:32 -07:00
dmaengine Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma 2015-02-18 08:49:20 -08:00
DocBook Merge branch 'mvebu/drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc 2015-06-19 22:07:07 +08:00
driver-model Char/Misc driver patches for 4.1-rc1 2015-04-21 09:42:58 -07:00
dvb
early-userspace
EDID
extcon
fault-injection
fb
filesystems Documentation: remove outdated information from automount-support.txt 2015-05-15 01:10:38 -04:00
firmware_class
fmc
frv
gpio fix documentation after renaming gpiod_set_array to gpiod_set_array_value 2015-06-04 10:46:43 +02:00
hid HID: sensor: Update document for custom sensor 2015-04-10 22:22:56 +02:00
hwmon hwmon: add driver for Microchip TC74 2015-06-21 22:54:53 -07:00
i2c i2c: slave: fix the example how to instantiate from userspace 2015-06-17 14:16:27 +02:00
ia64 virtual: Documentation: simplify and generalize paravirt_ops.txt 2015-02-13 17:15:44 +10:30
ide
infiniband
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2015-04-21 12:54:08 -07:00
ioctl platform/chrome: Add Chrome OS EC userspace device interface 2015-02-26 15:45:06 -08:00
isdn
ja_JP
kbuild Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2015-02-19 10:31:37 -08:00
kdump kernel: add panic_on_warn 2014-12-10 17:41:10 -08:00
ko_KR
laptops thinkpad_acpi: Add adaptive_kbd_mode sysfs attr 2015-03-03 09:00:08 -08:00
leds Documentation: leds: Add description of LED Flash class extension 2015-03-09 17:18:00 -07:00
locking Documentation changes for 3.20 2015-02-11 13:03:11 -08:00
m68k
memory-devices
metag
mic Documentation: Build mic/mpssd only for x86_64 2014-12-05 11:18:36 -05:00
mips
misc-devices Documentation/misc-devices/mei: Fix indentation of embedded code. 2015-01-29 12:56:20 -07:00
mmc
mn10300
mtd
namespaces
netlabel
networking Doc: networking: Fix URL for wiki.wireshark.org in udplite.txt 2015-06-12 14:21:29 -07:00
nfc
nios2 Documentation: Add documentation for Nios2 architecture 2014-12-08 12:56:06 +08:00
parisc
PCI The documentation tree update for 4.1. Numerous fixes, the overdue removal 2015-04-18 11:10:49 -04:00
pcmcia
phy
platform
power PM / runtime: add note about re-calling in during device probe() 2015-05-13 00:02:38 +02:00
powerpc powerpc/tm: Abort syscalls in active transactions 2015-06-19 17:10:28 +10:00
pps
prctl Documentation: Restrict TSC test code to x86 2014-10-28 08:46:27 -04:00
pti
ptp ptp: restore the makefile for building the test program. 2014-10-24 16:07:10 -04:00
rapidio
RCU Merge branches 'array.2015.05.27a', 'doc.2015.05.27a', 'fixes.2015.05.27a', 'hotplug.2015.05.27a', 'init.2015.05.27a', 'tiny.2015.05.27a' and 'torture.2015.05.27a' into HEAD 2015-05-27 13:00:49 -07:00
s390 s390/docs: Remove section about script debugging from Debugging390.txt 2015-01-15 11:11:14 +01:00
scheduler sched/dl/Documentation: Split Section 3 2015-05-19 08:39:21 +02:00
scsi st: implement tape statistics 2015-06-02 08:03:25 -07:00
security Smack: Updates for Smack documentation 2015-03-31 10:35:31 -07:00
serial pty: Fix input race when closing 2015-05-10 19:26:37 +02:00
sh
sound ASoC: Updates for v4.1 2015-04-13 14:14:29 +02:00
spi Documentation/spi/spidev_test.c: fix warning 2015-04-17 09:04:12 -04:00
sysctl watchdog: add watchdog_cpumask sysctl to assist nohz 2015-06-24 17:49:40 -07:00
target SCSI misc on 20150622 2015-06-23 15:55:44 -07:00
thermal Documentation: thermal: document of_cpufreq_cooling_register() 2015-01-06 14:39:17 -04:00
timers documentation: Update NO_HZ_FULL interaction with POSIX timers 2015-02-26 11:57:29 -08:00
tpm
trace coresight: Correcting documentation typographical error 2015-04-03 16:17:03 +02:00
usb usb: patches for v4.1 merge window 2015-03-24 22:57:49 +01:00
vDSO vdso: don't require 64-bit math in standalone test 2014-10-25 10:53:44 -04:00
video4linux [media] media/Documentation: New flag EXECUTE_ON_WRITE 2015-04-08 06:35:16 -03:00
virtual KVM: x86: mark legacy PCI device assignment as deprecated 2015-06-05 17:26:39 +02:00
vm The documentation tree update for 4.1. Numerous fixes, the overdue removal 2015-04-18 11:10:49 -04:00
w1
watchdog
wimax
x86 Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 17:59:09 -07:00
xtensa
zh_CN gpio: remove gpiod_sysfs_set_active_low 2015-05-12 10:46:53 +02:00
00-INDEX Update of Documentation/dmaengine/00-INDEX 2014-12-29 15:28:24 -07:00
applying-patches.txt
assoc_array.txt
atomic_ops.txt documentation: Clarify memory-barrier semantics of atomic operations 2015-02-26 11:57:31 -08:00
bad_memory.txt
basic_profiling.txt
bcache.txt
binfmt_misc.txt binfmt_misc: touch up documentation a bit 2014-10-14 02:18:16 +02:00
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt rmap: drop support of non-linear mappings 2015-02-10 14:30:31 -08:00
Changes Documentation: GNU is frequently spelled Gnu 2014-12-29 15:33:17 -07:00
circular-buffers.txt
clk.txt clk: Add rate constraints to clocks 2015-02-02 14:23:42 -08:00
coccinelle.txt
CodeOfConflict Code of Conflict 2015-02-27 11:44:24 -08:00
CodingStyle The documentation tree update for 4.1. Numerous fixes, the overdue removal 2015-04-18 11:10:49 -04:00
cpu-hotplug.txt cpumask: fix cpu-hotplug documentation 2015-03-05 13:37:01 +10:30
cpu-load.txt
cputopology.txt Documentation: Update cputopology.txt 2015-05-27 15:22:15 +02:00
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt
digsig.txt
DMA-API-HOWTO.txt PCI: Add pci_bus_addr_t 2015-05-29 17:21:45 -05:00
DMA-API.txt PCI: Add pci_bus_addr_t 2015-05-29 17:21:45 -05:00
DMA-attributes.txt
dma-buf-sharing.txt dma-buf: cleanup dma_buf_export() to make it easily extensible 2015-04-21 14:47:16 +05:30
DMA-ISA-LPC.txt
dontdiff
dynamic-debug-howto.txt
edac.txt
efi-stub.txt
eisa.txt
email-clients.txt Documentation/email-clients.txt: Fix one grammar mistake, add extra info about TB 2015-03-20 07:41:55 -06:00
flexible-arrays.txt
futex-requeue-pi.txt doc: Fix misnamed FUTEX_CMP_REQUEUE_PI op constants 2015-01-19 12:05:32 +01:00
gcov.txt
gdb-kernel-debugging.txt scripts/gdb: add basic documentation 2015-02-17 14:34:54 -08:00
highuid.txt
HOWTO Documentation: remove outdated references to the linux-next wiki 2014-10-28 09:06:11 -04:00
hsi.txt
hw_random.txt
hwspinlock.txt
init.txt
initrd.txt
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt ipmi:ssif: Ignore spaces when comparing I2C adapter names 2015-05-05 14:24:45 -05:00
IRQ-affinity.txt
IRQ-domain.txt IRQCHIP: Update docs regarding irq_domain_add_tree() 2015-04-01 17:21:35 +02:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kasan.txt kasan: show gcc version requirements in Kconfig and Documentation 2015-05-05 17:10:10 -07:00
kernel-doc-nano-HOWTO.txt
kernel-docs.txt
kernel-parameters.txt Power management and ACPI material for v4.2-rc1 2015-06-23 14:18:07 -07:00
kernel-per-CPU-kthreads.txt documentation: Update per-CPU kthreads documentation 2015-02-26 11:57:30 -08:00
kmemcheck.txt Documentation: update the CONFIG_DEBUG_PAGEALLOC description 2015-03-20 07:41:55 -06:00
kmemleak.txt Documentation: Add CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF case 2014-10-24 13:59:03 -04:00
kobject.txt kobject: grammar fix 2014-12-08 09:07:11 -05:00
kprobes.txt kprobes: Update Documentation/kprobes.txt 2015-03-20 07:41:55 -06:00
kref.txt
kselftest.txt kselftest: Move the docs to the Documentation dir 2014-11-24 10:49:54 -07:00
ldm.txt
local_ops.txt percpu: update local_ops.txt to reflect this_cpu operations 2014-12-13 12:42:53 -08:00
lockup-watchdogs.txt watchdog: add watchdog_cpumask sysctl to assist nohz 2015-06-24 17:49:40 -07:00
logo.gif
logo.txt
lzo.txt
magic-number.txt
mailbox.txt Documentation: Fix a typo in mailbox.txt 2014-11-03 11:54:50 -05:00
Makefile Documentation: Remove ZBOOT MMC/SDHI utility and docs 2015-02-24 06:45:25 +09:00
ManagementStyle
md-cluster.txt md-cluster: Design Documentation 2015-02-23 07:16:46 -06:00
md.txt
media-framework.txt
memory-barriers.txt Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-06-22 14:54:22 -07:00
memory-hotplug.txt mem-hotplug: fix typo in Documentation/memory-hotplug.txt 2015-03-20 07:41:55 -06:00
module-signing.txt modsign: change default key details 2015-04-30 09:35:41 -07:00
mono.txt
nommu-mmap.txt fs: introduce f_op->mmap_capabilities for nommu mmap support 2015-01-20 14:02:58 -07:00
numastat.txt
oops-tracing.txt livepatch: kernel: add TAINT_LIVEPATCH 2014-12-22 15:40:48 +01:00
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt
phy.txt phy: improved lookup method 2014-11-21 19:48:50 +05:30
pi-futex.txt
pinctrl.txt pinctrl: fix example .get_group_pins implementation signature 2015-03-18 02:02:20 +01:00
pnp.txt
preempt-locking.txt x86/fpu: Rename math_state_restore() to fpu__restore() 2015-05-19 15:47:18 +02:00
printk-formats.txt The documentation tree update for 4.1. Numerous fixes, the overdue removal 2015-04-18 11:10:49 -04:00
pwm.txt
ramoops.txt pstore-ram: Allow optional mapping with pgprot_noncached 2014-12-11 13:38:31 -08:00
rbtree.txt
remoteproc.txt
rfkill.txt rfkill: document rfkill module parameters 2015-01-09 23:22:12 +01:00
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt Documentation, split up rtc.txt into documentation and test file 2015-03-24 22:01:58 -06:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
SM501.txt
smsc_ece1099.txt
sparse.txt
stable_api_nonsense.txt
stable_kernel_rules.txt stable_kernel_rules: Add clause about specification of kernel versions to patch. 2015-03-26 23:52:24 +01:00
static-keys.txt
SubmitChecklist
SubmittingDrivers
SubmittingPatches checkpatch, SubmittingPatches: suggest line wrapping commit messages at 75 columns 2015-04-17 09:03:57 -04:00
svga.txt
sysfs-rules.txt
sysrq.txt
this_cpu_ops.txt
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt vfio: powerpc/spapr: Support Dynamic DMA windows 2015-06-11 15:16:55 +10:00
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt
volatile-considered-harmful.txt
workqueue.txt
xillybus.txt
xz.txt
zorro.txt