linux-sg2042/drivers
Thomas Hellstrom 08295b3b5b locking: Implement an algorithm choice for Wound-Wait mutexes
The current Wound-Wait mutex algorithm is actually not Wound-Wait but
Wait-Die. Implement also Wound-Wait as a per-ww-class choice. Wound-Wait
is, contrary to Wait-Die a preemptive algorithm and is known to generate
fewer backoffs. Testing reveals that this is true if the
number of simultaneous contending transactions is small.
As the number of simultaneous contending threads increases, Wait-Wound
becomes inferior to Wait-Die in terms of elapsed time.
Possibly due to the larger number of held locks of sleeping transactions.

Update documentation and callers.

Timings using git://people.freedesktop.org/~thomash/ww_mutex_test
tag patch-18-06-15

Each thread runs 100000 batches of lock / unlock 800 ww mutexes randomly
chosen out of 100000. Four core Intel x86_64:

Algorithm    #threads       Rollbacks  time
Wound-Wait   4              ~100       ~17s.
Wait-Die     4              ~150000    ~19s.
Wound-Wait   16             ~360000    ~109s.
Wait-Die     16             ~450000    ~82s.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Co-authored-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
2018-07-03 09:44:36 +02:00
..
accessibility
acpi pwm: Changes for v4.18-rc1 2018-06-14 16:25:43 +09:00
amba Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2018-06-06 13:49:25 -07:00
android treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
ata treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
atm treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
auxdisplay treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
base Additional power management updates for 4.18-rc1 2018-06-13 07:24:18 -07:00
bcma dma-mapping updates for 4.18: 2018-06-04 10:58:12 -07:00
block The main piece is a set of libceph changes that revamps how OSD 2018-06-15 07:24:58 +09:00
bluetooth Bluetooth: btusb: Add additional device ID for RTL8822BE 2018-05-30 15:45:01 +02:00
bus - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
cdrom treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
char docs: Fix some broken references 2018-06-15 18:10:01 -03:00
clk docs: Fix some broken references 2018-06-15 18:10:01 -03:00
clocksource treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
connector Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-06-06 18:39:49 -07:00
cpufreq Additional power management updates for 4.18-rc1 2018-06-13 07:24:18 -07:00
cpuidle powerpc updates for 4.18 2018-06-07 10:23:33 -07:00
crypto treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
dax libnvdimm for 4.18 2018-06-08 17:21:52 -07:00
dca
devfreq treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
dio
dma fix a series of Documentation/ broken file name references 2018-06-15 18:10:01 -03:00
dma-buf locking: Implement an algorithm choice for Wound-Wait mutexes 2018-07-03 09:44:36 +02:00
edac treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
eisa
extcon treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
firewire treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
firmware Merge branch 'akpm' (patches from Andrew) 2018-06-15 08:51:42 +09:00
fmc treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
fpga
fsi
gpio treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
gpu locking: Implement an algorithm choice for Wound-Wait mutexes 2018-07-03 09:44:36 +02:00
hid docs: fix broken references with multiple hints 2018-06-15 18:10:01 -03:00
hsi
hv treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
hwmon treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
hwspinlock hwspinlock updates for v4.18 2018-06-11 12:09:19 -07:00
hwtracing treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
i2c Merge branch 'i2c/for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2018-06-14 16:21:46 +09:00
ide treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
idle
iio treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
infiniband treewide: Use array_size() in kvzalloc_node() 2018-06-12 16:19:22 -07:00
input docs: Fix some broken references 2018-06-15 18:10:01 -03:00
iommu - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
ipack treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
irqchip treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
isdn treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
leds treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
lightnvm docs: Fix some broken references 2018-06-15 18:10:01 -03:00
macintosh powerpc updates for 4.18 2018-06-07 10:23:33 -07:00
mailbox treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
mcb
md docs: Fix some broken references 2018-06-15 18:10:01 -03:00
media drm-misc-next for 4.19: 2018-06-22 12:58:08 +10:00
memory - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
memstick treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
message treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
mfd Merge branch 'i2c/for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2018-06-14 16:21:46 +09:00
misc Merge branch 'i2c/for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2018-06-14 16:21:46 +09:00
mmc treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
mtd - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
mux
net Solve a series of broken links for files under Documentation: 2018-06-17 05:25:18 +09:00
nfc treewide: devm_kmalloc() -> devm_kmalloc_array() 2018-06-12 16:19:22 -07:00
ntb - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
nubus Char/Misc driver patches for 4.18-rc1 2018-06-05 16:20:22 -07:00
nvdimm Merge branch 'for-4.18/mcsafe' into libnvdimm-for-next 2018-06-08 15:16:44 -07:00
nvme Merge branch 'nvme-4.18' of git://git.infradead.org/nvme into for-linus 2018-06-15 08:11:05 -06:00
nvmem treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
of - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
opp treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
oprofile treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
parisc dma-mapping updates for 4.18: 2018-06-04 10:58:12 -07:00
parport docs: Fix some broken references 2018-06-15 18:10:01 -03:00
pci - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
pcmcia treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
perf drivers/bus: arm-cci: fix build warnings 2018-05-29 16:38:16 +01:00
phy Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-06-06 18:39:49 -07:00
pinctrl treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
platform fix a series of Documentation/ broken file name references 2018-06-15 18:10:01 -03:00
pnp media updates for v4.18-rc1 2018-06-07 12:34:37 -07:00
power treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
powercap treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
pps
ps3
ptp
pwm pwm: Changes for v4.18-rc1 2018-06-14 16:25:43 +09:00
rapidio treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
ras
regulator treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
remoteproc treewide: use PHYS_ADDR_MAX to avoid type casting ULLONG_MAX 2018-06-15 07:55:25 +09:00
reset - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
rpmsg rpmsg: smd: do not use mananged resources for endpoints and channels 2018-06-04 12:35:03 -07:00
rtc - New Device Support 2018-06-11 07:20:17 -07:00
s390 treewide: Use array_size() in vzalloc() 2018-06-12 16:19:22 -07:00
sbus fix a series of Documentation/ broken file name references 2018-06-15 18:10:01 -03:00
scsi SCSI fixes on 20180613 2018-06-14 16:35:32 +09:00
sfi
sh treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
siox
slimbus treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
sn
soc treewide: use PHYS_ADDR_MAX to avoid type casting ULLONG_MAX 2018-06-15 07:55:25 +09:00
soundwire docs: Fix more broken references 2018-06-15 18:11:26 -03:00
spi treewide: devm_kzalloc() -> devm_kcalloc() 2018-06-12 16:19:22 -07:00
spmi
ssb
staging drm-misc-next for 4.19: 2018-06-22 12:58:08 +10:00
target treewide: Use array_size() in vzalloc() 2018-06-12 16:19:22 -07:00
tc
tee drm-misc-next for 4.19: 2018-06-22 12:58:08 +10:00
thermal - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
thunderbolt
tty vfs/y2038: inode timestamps conversion to timespec64 2018-06-15 07:31:07 +09:00
uio treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
usb vfs/y2038: inode timestamps conversion to timespec64 2018-06-15 07:31:07 +09:00
uwb treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
vfio VFIO updates for v4.18 2018-06-12 13:11:26 -07:00
vhost virtio, vhost: features, fixes 2018-06-16 06:35:02 +09:00
video Solve a series of broken links for files under Documentation: 2018-06-17 05:25:18 +09:00
virt treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
virtio virtio, vhost: features, fixes 2018-06-16 06:35:02 +09:00
visorbus
vlynq
vme
w1 Char/Misc driver patches for 4.18-rc1 2018-06-05 16:20:22 -07:00
watchdog MIPS changes for 4.18 2018-06-12 12:56:02 -07:00
xen treewide: kvmalloc() -> kvmalloc_array() 2018-06-12 16:19:22 -07:00
zorro - Introduce arithmetic overflow test helper functions (Rasmus) 2018-06-06 17:27:14 -07:00
Kconfig
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