Add complete support for full hierarchical scheduling, with a cgroups
interface. Full hierarchical scheduling is implemented through the
'entity' abstraction: both bfq_queues, i.e., the internal BFQ queues
associated with processes, and groups are represented in general by
entities. Given the bfq_queues associated with the processes belonging
to a given group, the entities representing these queues are sons of
the entity representing the group. At higher levels, if a group, say
G, contains other groups, then the entity representing G is the parent
entity of the entities representing the groups in G.
Hierarchical scheduling is performed as follows: if the timestamps of
a leaf entity (i.e., of a bfq_queue) change, and such a change lets
the entity become the next-to-serve entity for its parent entity, then
the timestamps of the parent entity are recomputed as a function of
the budget of its new next-to-serve leaf entity. If the parent entity
belongs, in its turn, to a group, and its new timestamps let it become
the next-to-serve for its parent entity, then the timestamps of the
latter parent entity are recomputed as well, and so on. When a new
bfq_queue must be set in service, the reverse path is followed: the
next-to-serve highest-level entity is chosen, then its next-to-serve
child entity, and so on, until the next-to-serve leaf entity is
reached, and the bfq_queue that this entity represents is set in
service.
Writeback is accounted for on a per-group basis, i.e., for each group,
the async I/O requests of the processes of the group are enqueued in a
distinct bfq_queue, and the entity associated with this queue is a
child of the entity associated with the group.
Weights can be assigned explicitly to groups and processes through the
cgroups interface, differently from what happens, for single
processes, if the cgroups interface is not used (as explained in the
description of the previous patch). In particular, since each node has
a full scheduler, each group can be assigned its own weight.
Signed-off-by: Fabio Checconi <fchecconi@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We tag as v0 the version of BFQ containing only BFQ's engine plus
hierarchical support. BFQ's engine is introduced by this commit, while
hierarchical support is added by next commit. We use the v0 tag to
distinguish this minimal version of BFQ from the versions containing
also the features and the improvements added by next commits. BFQ-v0
coincides with the version of BFQ submitted a few years ago [1], apart
from the introduction of preemption, described below.
BFQ is a proportional-share I/O scheduler, whose general structure,
plus a lot of code, are borrowed from CFQ.
- Each process doing I/O on a device is associated with a weight and a
(bfq_)queue.
- BFQ grants exclusive access to the device, for a while, to one queue
(process) at a time, and implements this service model by
associating every queue with a budget, measured in number of
sectors.
- After a queue is granted access to the device, the budget of the
queue is decremented, on each request dispatch, by the size of the
request.
- The in-service queue is expired, i.e., its service is suspended,
only if one of the following events occurs: 1) the queue finishes
its budget, 2) the queue empties, 3) a "budget timeout" fires.
- The budget timeout prevents processes doing random I/O from
holding the device for too long and dramatically reducing
throughput.
- Actually, as in CFQ, a queue associated with a process issuing
sync requests may not be expired immediately when it empties. In
contrast, BFQ may idle the device for a short time interval,
giving the process the chance to go on being served if it issues
a new request in time. Device idling typically boosts the
throughput on rotational devices, if processes do synchronous
and sequential I/O. In addition, under BFQ, device idling is
also instrumental in guaranteeing the desired throughput
fraction to processes issuing sync requests (see [2] for
details).
- With respect to idling for service guarantees, if several
processes are competing for the device at the same time, but
all processes (and groups, after the following commit) have
the same weight, then BFQ guarantees the expected throughput
distribution without ever idling the device. Throughput is
thus as high as possible in this common scenario.
- Queues are scheduled according to a variant of WF2Q+, named
B-WF2Q+, and implemented using an augmented rb-tree to preserve an
O(log N) overall complexity. See [2] for more details. B-WF2Q+ is
also ready for hierarchical scheduling. However, for a cleaner
logical breakdown, the code that enables and completes
hierarchical support is provided in the next commit, which focuses
exactly on this feature.
- B-WF2Q+ guarantees a tight deviation with respect to an ideal,
perfectly fair, and smooth service. In particular, B-WF2Q+
guarantees that each queue receives a fraction of the device
throughput proportional to its weight, even if the throughput
fluctuates, and regardless of: the device parameters, the current
workload and the budgets assigned to the queue.
- The last, budget-independence, property (although probably
counterintuitive in the first place) is definitely beneficial, for
the following reasons:
- First, with any proportional-share scheduler, the maximum
deviation with respect to an ideal service is proportional to
the maximum budget (slice) assigned to queues. As a consequence,
BFQ can keep this deviation tight not only because of the
accurate service of B-WF2Q+, but also because BFQ *does not*
need to assign a larger budget to a queue to let the queue
receive a higher fraction of the device throughput.
- Second, BFQ is free to choose, for every process (queue), the
budget that best fits the needs of the process, or best
leverages the I/O pattern of the process. In particular, BFQ
updates queue budgets with a simple feedback-loop algorithm that
allows a high throughput to be achieved, while still providing
tight latency guarantees to time-sensitive applications. When
the in-service queue expires, this algorithm computes the next
budget of the queue so as to:
- Let large budgets be eventually assigned to the queues
associated with I/O-bound applications performing sequential
I/O: in fact, the longer these applications are served once
got access to the device, the higher the throughput is.
- Let small budgets be eventually assigned to the queues
associated with time-sensitive applications (which typically
perform sporadic and short I/O), because, the smaller the
budget assigned to a queue waiting for service is, the sooner
B-WF2Q+ will serve that queue (Subsec 3.3 in [2]).
- Weights can be assigned to processes only indirectly, through I/O
priorities, and according to the relation:
weight = 10 * (IOPRIO_BE_NR - ioprio).
The next patch provides, instead, a cgroups interface through which
weights can be assigned explicitly.
- If several processes are competing for the device at the same time,
but all processes and groups have the same weight, then BFQ
guarantees the expected throughput distribution without ever idling
the device. It uses preemption instead. Throughput is then much
higher in this common scenario.
- ioprio classes are served in strict priority order, i.e.,
lower-priority queues are not served as long as there are
higher-priority queues. Among queues in the same class, the
bandwidth is distributed in proportion to the weight of each
queue. A very thin extra bandwidth is however guaranteed to the Idle
class, to prevent it from starving.
- If the strict_guarantees parameter is set (default: unset), then BFQ
- always performs idling when the in-service queue becomes empty;
- forces the device to serve one I/O request at a time, by
dispatching a new request only if there is no outstanding
request.
In the presence of differentiated weights or I/O-request sizes,
both the above conditions are needed to guarantee that every
queue receives its allotted share of the bandwidth (see
Documentation/block/bfq-iosched.txt for more details). Setting
strict_guarantees may evidently affect throughput.
[1] https://lkml.org/lkml/2008/4/1/234https://lkml.org/lkml/2008/11/11/148
[2] P. Valente and M. Andreolini, "Improving Application
Responsiveness with the BFQ Disk I/O Scheduler", Proceedings of
the 5th Annual International Systems and Storage Conference
(SYSTOR '12), June 2012.
Slightly extended version:
http://algogroup.unimore.it/people/paolo/disk_sched/bfq-v1-suite-
results.pdf
Signed-off-by: Fabio Checconi <fchecconi@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
i.MX device tree updates for 4.12:
- New board support: I2SE's i.MX28 Duckbill-2 boards, Gateworks Ventana
i.MX6 GW5903/GW5904, Zodiac Inflight Innovations RDU2 board, Engicam
i.CoreM6 Quad/Dual OpenFrame modules, Boundary Device i.MX6 Quad Plus
SOM.
- Improve compatible string for i.MX50 eSDHC, i.MX7S SRC devices and
i.MX6SX UART device.
- Add interrupts for switch and PHY devices on VF610 ZII Devel C board.
- Add LVDS, LCD backlight, touchscreen and SAI2 support for i.MX6
icore, geam, and isiot boards.
- A series from Lucas Stach to improve i.MX6Q Plus device tree and add
PRE/PRG devices.
- A series from Stefan Agner to update imx7-colibri device tree
regarding to display, PMIC/regulator support.
- Fix PCI bus DTC warnings seen with the latest compiler.
- Set default phy_type and dr_mode for i.MX25 USBOTG port.
- A couple of small improvements on i.MX25 pin function DT header.
- Add audio support for imx6q-cm-fx6 board using Wolfson wm8731 codec
which is muxed to SSI2 device.
- Other random updates, small fixes and trivial cleanups.
* tag 'imx-dt-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux: (56 commits)
ARM: dts: imx6q-utilite-pro: add hpd gpio
ARM: dts: imx6qp-sabresd: Set reg_arm regulator supply
ARM: dts: imx6qdl-sabresd: Set LDO regulator supply
ARM: dts: imx: add Gateworks Ventana GW5903 support
ARM: dts: i.MX25: add AIPS control registers
ARM: dts: imx7-colibri: add Carrier Board 3.3V/5V regulators
ARM: dts: imx7-colibri: remove 1.8V fixed regulator
ARM: dts: imx7-colibri: allow to disable Ethernet rail
ARM: dts: imx7-colibri: fix PMIC voltages
ARM: dts: imx7-colibri: use OF graph to describe the display
ARM: dts: imx6qp-nitrogen6_som2: add Quad Plus variant of the SOM
ARM: dts: imx6q-icore: Add touchscreen node
ARM: dts: vf610-zii-dev-rev-b: change switch2 label
ARM: dts: imx6ul-[geam|isiot]: Add sai2 node
ARM: dts: imx6ul-isiot-common: Add touchscreen node
ARM: dts: imx6ul-isiot: Add i2c nodes
ARM: dts: imx6ul-isiot: Add imx6ul-isiot-common.dtsi
ARM: dts: imx6ul-isiot: Add backlight support for lcdif
ARM: dts: imx6ul-geam: Add backlight support for lcdif
ARM: dts: imx6: add ZII RDU2 boards
...
Signed-off-by: Olof Johansson <olof@lixom.net>
Support for the usb-sata controller on the rock2 and another new rk3288
board, the phyCORE som and its PCM-947 carrier board from Phytec.
* tag 'v4.12-rockchip-dts32-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip:
ARM: dts: rockchip: Add support for PCM-947 carrier board
dt-bindings: Document Phytec phyCORE-RK3288 RDK
ARM: dts: rockchip: Add support for phyCORE-RK3288 SoM
ARM: dts: rockchip: Enable sata support on rock2 square
Signed-off-by: Olof Johansson <olof@lixom.net>
i.MX drivers updates for 4.12:
- A series from Lucas Stach which partly rewrites the imx gpc driver
to support multiple power domains, and moves the related code from
imx platform into drivers folder.
- A series from Dong Aisheng which fixes the issues with Lucas' code
changes and improves things.
- Add workaround for i.MX6QP hardware erratum ERR009619 that is PRE
clocks may be stalled during the power up sequencing of the PU power
domain.
- Add imx-gpcv2 driver to support power domains managed by GPCv2 IP
block found on i.MX7 series of SoCs.
* tag 'imx-drivers-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
soc: imx: gpc: add workaround for i.MX6QP to the GPC PD driver
dt-bindings: imx-gpc: add i.MX6 QuadPlus compatible
soc: imx: gpc: add defines for domain index
soc: imx: Add GPCv2 power gating driver
dt-bindings: Add GPCv2 power gating driver
soc: imx: gpc: remove unnecessary readable_reg callback
dt-bindings: imx-gpc: correct the DOMAIN_INDEX using
soc: imx: gpc: keep PGC_X_CTRL name align with reference manual
soc: imx: gpc: fix comment when power up domain
soc: imx: gpc: fix imx6sl gpc power domain regression
soc: imx: gpc: fix domain_index sanity check issue
soc: imx: gpc: fix the wrong using of regmap cache
soc: imx: gpc: fix gpc clk get error handling
soc: imx: move PGC handling to a new GPC driver
dt-bindings: add multidomain support to i.MX GPC DT binding
Signed-off-by: Olof Johansson <olof@lixom.net>
ARM64: DT: Hisilicon SoC DT updates for 4.12
- Reset the hi6220 mmc hosts to avoid hang
- Add the binding for the hi3798cv200 SoC and the poplar board
- Add basic dts files to support the hi3798cv200 poplar board
- Enable the Mbigen, XGE, RoCE and SAS for the hip07 d05 board
- Add driver strength MACRO for the hi3660 SoC
- Add the pinctrl dtsi file for hikey960 board to configure the pins
* tag 'hisi-arm64-dt-for-4.12' of git://github.com/hisilicon/linux-hisi:
arm64: dts: hisi: add pinctrl dtsi file for HiKey960 development board
arm64: dts: hisi: add drive strength levels of the pins for Hi3660 SoC
arm64: dts: hisi: enable the NIC and SAS for the hip07-d05 board
arm64: dts: hisi: add SAS nodes for the hip07 SoC
arm64: dts: hisi: add RoCE nodes for the hip07 SoC
arm64: dts: hisi: add network related nodes for the hip07 SoC
arm64: dts: hisi: add mbigen nodes for the hip07 SoC
arm64: dts: hisilicon: add dts files for hi3798cv200-poplar board
dt-bindings: arm: hisilicon: add bindings for hi3798cv200 SoC and Poplar board
arm64: dts: hi6220: Reset the mmc hosts
Signed-off-by: Olof Johansson <olof@lixom.net>
Freescale arm64 device tree updates for 4.12:
- Add support of LS2088A SoC, which is a derivative of existing
LS2080A SoC, and the major difference is on ARM cores.
- Add support of LS1088A SoC which includes eight Cortex-A53 cores
with 32 KB L1 D-cache and I-cache respectively.
- Add crypto and thermal device support for LS1012A platform.
- Add ECC register region for SATA device on LS1012A, LS1043A and
LS1046A platforms.
* tag 'imx-dt64-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
dt-bindings: arm: Add entry for FSL LS1088A RDB, QDS boards
dt-bindings: clockgen: Add compatible string for LS1088A
arm64: dts: Add support for FSL's LS1088A SoC
arm64: dts: ls1012a: add crypto node
arm64: dts: ls1012a: add thermal monitor node
arm64: dts: updated sata node on ls1012a platform
arm64: dts: added ecc register address to sata node on ls1046a
arm64: dts: added ecc register address to sata node on ls1043a
arm64: dts: freescale: ls2088a: Add DTS support for FSL's LS2088A SoC
arm64: dts: freescale: ls2080a: Split devicetree for code resuability
dt-bindings: Add compatible for LS2088A QDS and RDB board
Signed-off-by: Olof Johansson <olof@lixom.net>
Basic support for new rk3328, a 4-core Cortex-A53 soc and a fix for the
default memory definition on the px5 eval board. While the bootloader
should already override it with the actual amount, it's better to not
carry around wrong values.
* tag 'v4.12-rockchip-dts64-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip:
arm64: dts: rockchip: fix the memory size of PX5 Evaluation board
arm64: dts: rockchip: add RK3328 eavluation board devicetree
dt-bindings: document rockchip rk3328-evb board
arm64: dts: rockchip: add core dtsi file for RK3328 SoCs
dt-bindings: add binding for rk3328-grf
Signed-off-by: Olof Johansson <olof@lixom.net>
dt-bindings: Updates for v4.12-rc1
This contains an update for the flow controller device tree binding as
well as the addition of the binding for the GP10B GPU found on the new
Tegra186 (Parker) SoC.
* tag 'tegra-for-4.12-dt-bindings' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux:
dt-bindings: Add documentation for GP10B GPU
dt-bindings: tegra: Update compatible strings for Tegra flowctrl
Signed-off-by: Olof Johansson <olof@lixom.net>
soc/tegra: Core SoC changes for v4.12-rc1
This contains PMC support for Tegra186 as well as a proper driver for
the flow controller found on SoCs up to Tegra210. This also turns the
fuse driver into an explicitly non-modular driver.
* tag 'tegra-for-4.12-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux:
soc/tegra: Add initial flowctrl support for Tegra132/210
soc/tegra: flowctrl: Add basic platform driver
soc/tegra: Move Tegra flowctrl driver
ARM: tegra: Remove unnecessary inclusion of flowctrl header
soc: tegra: make fuse-tegra explicitly non-modular
soc/tegra: Fix link errors with PMC disabled
soc/tegra: Implement Tegra186 PMC support
Signed-off-by: Olof Johansson <olof@lixom.net>
ARM SOC PM domain support for 4.12
Dave Gerlach (5):
PM / Domains: Add generic data pointer to genpd data struct
PM / Domains: Do not check if simple providers have phandle cells
dt-bindings: Add TI SCI PM Domains
soc: ti: Add ti_sci_pm_domains driver
ARM: keystone: Drop PM domain support for k2g
* tag 'arm-soc-pmdomain' of git://git.kernel.org/pub/scm/linux/kernel/git/ssantosh/linux-keystone:
ARM: keystone: Drop PM domain support for k2g
soc: ti: Add ti_sci_pm_domains driver
dt-bindings: Add TI SCI PM Domains
PM / Domains: Do not check if simple providers have phandle cells
PM / Domains: Add generic data pointer to genpd data struct
Signed-off-by: Olof Johansson <olof@lixom.net>
Allwinner DT changes for 4.12
As usual a number of changes, among which:
- All the sun5i DTSI has been reworked based on the new documentation and
the IPs that are actually found in all those SoCs. Part of that rework
also brought the GR8 DTSI to include sun5i.dtsi
- Mali devfreq and thermal throttling support on the A33
- AC power supplies for the AXP209 and AXP22X PMIC
- CAN support for the A20
- CPUFreq-based thermal throttling for the A33
- New board: NanoPi NEO Air
* tag 'sunxi-dt-for-4.12' of https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux: (38 commits)
ARM: sun8i: sina33: add highest OPP of CPUs
ARM: sun8i: a33: Add devfreq-based GPU cooling
ARM: sun8i: a33: add CPU thermal throttling
ARM: sun8i: a33: add thermal sensor
ARM: dts: sun7i: fix device node ordering
ARM: dts: sun4i: fix device node ordering
ARM: dts: sun7i: Add can0_pins_a pinctrl settings
ARM: dts: sun7i: Add CAN node
ARM: dts: sun4i: Add can0_pins_a pinctrl settings
ARM: dts: sun4i: Add CAN node
ARM: sun7i: cubietruck: enable ACIN und USB power supply subnode
ARM: dts: sun5i: Add interrupt for display backend
dt-bindings: display: sun4i: Add display backend interrupt to device tree binding
ARM: dts: sun7i: Use axp209.dtsi on A20-OLinuXino-Micro
ARM: dts: sun6i: sina31s: Enable SPDIF out
ARM: sun8i: sina33: add cpu-supply
ARM: sun8i: a33: add all operating points
ARM: sun5i: chip: enable ACIN power supply subnode
ARM: dts: sun8i: sina33: enable ACIN power supply subnode
ARM: dtsi: axp22x: add AC power supply subnode
...
Signed-off-by: Olof Johansson <olof@lixom.net>
STM32 SOC updates for v4.12, round 1.
Highlights:
----------
- Create a dedicated Kconfig for STM32 machine
- Add support of STM32H743 MCU
* tag 'stm32-soc-for-v4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/atorgue/stm32:
ARM: stm32: Add a new SOC - STM32H743
ARM: stm32: Introduce MACH_STM32H743 flag
ARM: stm32: create dedicated kconfig for STM32 machine
Signed-off-by: Olof Johansson <olof@lixom.net>
STM32 DT updates for v4.12, round 1
Highlights:
----------
- ADD RTC support on STM32F746 MCU
- Enable RTC on STM32F746 Eval board
- Enable clocks on STM32F746 MCU
- Enable DMA, pwm1 and pwm3 on STM32F429I Eval
- Add support of STM32H743 MCU and his Eval board
- Enable USB HS and FS on STM32F469 Disco board
* tag 'stm32-dt-for-v4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/atorgue/stm32:
dt-bindings: Document the STM32 USB OTG DWC2 core binding
ARM: dts: stm32: Enable USB HS in FS mode (embedded phy) on stm32f429-disco
ARM: dts: stm32: Enable USB FS on stm32f469-disco
ARM: dts: stm32: Add USB FS support for STM32F429 MCU
ARM: dts: stm32: Add STM32H743 MCU and STM32H743i-EVAL board
ARM: dts: stm32: Enable pwm1 and pwm3 on stm32f429i-eval
ARM: dts: stm32: Enable dma by default on stm32f4 adc
ARM: dts: stm32: enable RTC on stm32746g-eval
ARM: dts: stm32: Add RTC support for STM32F746 MCU
ARM: dts: stm32: set HSE_RTC clock frequency to 1 MHz on stm32f746
dt-bindings: mfd: Add STM32F7 RCC numeric constants into DT include file
ARM: dts: stm32: Enable clocks for STM32F746 MCU
Signed-off-by: Olof Johansson <olof@lixom.net>
The documentation incorrectly mentions MENU and INTEGER_MENU
at struct v4l2_querymenu table as if they were flags. They're
not: they're types.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Remove spurious '-' in the VSP1 hgo table.
This resulted in a weird dot character that also caused
the row to be double-height.
We used to have it on other tables, but we got rid of them
on changeset 8ed29e302d ("[media] subdev-formats.rst: remove
spurious '-'").
Fixes: 14d6653871 ("[media] v4l: Define a pixel format for the R-Car VSP1 1-D histogram engine")
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Remove spurious duplicate '-' in the Bayer Formats description. This resulted in a
weird dot character that also caused the row to be double-height.
The - character was probably used originally as indicator of an unused bit, but as the
number of columns was increased it was never used for the new columns.
Other tables do not use '-' either, so just remove it.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
A group of Linux kernel hackers reported chasing a bug that resulted
from their assumption that SLAB_DESTROY_BY_RCU provided an existence
guarantee, that is, that no block from such a slab would be reallocated
during an RCU read-side critical section. Of course, that is not the
case. Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire
slab of blocks.
However, there is a phrase for this, namely "type safety". This commit
therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order
to avoid future instances of this sort of confusion.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
[ paulmck: Add comments mentioning the old name, as requested by Eric
Dumazet, in order to help people familiar with the old name find
the new one. ]
Acked-by: David Rientjes <rientjes@google.com>
The rcu_all_qs() and rcu_note_context_switch() do a series of checks,
taking various actions to supply RCU with quiescent states, depending
on the outcomes of the various checks. This is a bit much for scheduling
fastpaths, so this commit creates a separate ->rcu_urgent_qs field in
the rcu_dynticks structure that acts as a global guard for these checks.
Thus, in the common case, rcu_all_qs() and rcu_note_context_switch()
check the ->rcu_urgent_qs field, find it false, and simply return.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
The rcu_momentary_dyntick_idle() function scans the RCU flavors, checking
that one of them still needs a quiescent state before doing an expensive
atomic operation on the ->dynticks counter. However, this check reduces
overhead only after a rare race condition, and increases complexity. This
commit therefore removes the scan and the mechanism enabling the scan.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_qs_ctr variable is yet another isolated per-CPU variable,
so this commit pulls it into the pre-existing rcu_dynticks per-CPU
structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_sched_qs_mask variable is yet another isolated per-CPU variable,
so this commit pulls it into the pre-existing rcu_dynticks per-CPU
structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Do not recommend people write to Dominic, rather everyone should be using
linux-input mailing list.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This is relatively esoteric, and knowing that we don't have it makes life
easier in some cases rather than just an eventual -EINVAL from
pci_mmap_page_range().
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Most of the almost-identical versions of pci_mmap_page_range() silently
ignore the 'write_combine' argument and give uncached mappings.
Yet we allow the PCIIOC_WRITE_COMBINE ioctl in /proc/bus/pci, expose the
'resourceX_wc' file in sysfs, and allow an attempted mapping to apparently
succeed.
To fix this, introduce a macro arch_can_pci_mmap_wc() which indicates
whether the platform can do a write-combining mapping. On x86 this ends up
being pat_enabled(), while the few other platforms that support it can just
set it to a literal '1'.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Jonathan writes:
Fourth set of IIO new device support, features and cleanups for the 4.12 cycle
New device support
* max1117, 1118 and 1119
- new ADC driver
* max9611
- new ADC driver
* pm8xxx hk/xoadc
- new driver with some shared features broken out from the SPMI vadc.
* sun4i-gpadc
- A33 thermal sensor support (with associated rework)
* stm32-dac
- new driver and bindings
* stm32 trigger
- enable support of quadrature encoder device and counter modes
Features
* apds9960
- use the runtime pm for normal suspend
* stm32-adc
- add opition to sest resolution via devicetree
* xoadc
- augment DT bindings to deal with some weird mux cases
Cleanups
* ad5933
- protect direct mode using claim and release helpers
* ade7759
- S_IRUGO and friends to octal in two goes
* adis16203
- drop unnecessary brackets
* hid-sensor
- fix unbalanced pm_runtieme_enable error when probing after remove
* lsm6dsx
- use actual part numbers for device name when known
- simplify data read pin parsing
* mpu3050
- avoid double reporting errors
Unfortunately, Sphinx (or LaTeX) can't handle literal blocks inside
footnotes. So, just use normal text for the two literal code-blocks that
documents the output of /sys/kernel/debug/usb/devices for xpad devices.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
The /proc/bus/usb/devices got moved to sysfs. It is now sitting at:
/sys/kernel/debug/usb/devices
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Stop saying that API is experimental and that only USB is supported,
acknowledge that evdev is the preferred interface, and remove paragraph
encouraging people sending snail mail to Vojtech :) along with his email.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Split input documentation into several groups: kernel- and user-facing, and
notes about individual device drivers. Move device drivers docs into a
separate subdirectory.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Consolidate use instructions and userspace API notes into the same chapter;
remove completely obsolete references, move into a separate subdirectory.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
The driver has been converted to use generic device properties, so
stop referring to platform data.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Update the CSI-2 bus documentation to tell that the LP-11 mode is not
mandatory as there are transmitters that cannot be explicitly set to LP-11
mode. Instead, say that this what the transmitter drivers shall do if
possible.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Johan Hedberg says:
====================
pull request: bluetooth-next 2017-04-14
Here's the main batch of Bluetooth & 802.15.4 patches for the 4.12
kernel.
- Many fixes to 6LoWPAN, in particular for BLE
- New CA8210 IEEE 802.15.4 device driver (accounting for most of the
lines of code added in this pull request)
- Added Nokia Bluetooth (UART) HCI driver
- Some serdev & TTY changes that are dependencies for the Nokia
driver (with acks from relevant maintainers and an agreement that
these come through the bluetooth tree)
- Support for new Intel Bluetooth device
- Various other minor cleanups/fixes here and there
Please let me know if there are any issues pulling. Thanks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch introduces pblk, a host-side translation layer for
Open-Channel SSDs to expose them like block devices. The translation
layer allows data placement decisions, and I/O scheduling to be
managed by the host, enabling users to optimize the SSD for their
specific workloads.
An open-channel SSD has a set of LUNs (parallel units) and a
collection of blocks. Each block can be read in any order, but
writes must be sequential. Writes may also fail, and if a block
requires it, must also be reset before new writes can be
applied.
To manage the constraints, pblk maintains a logical to
physical address (L2P) table, write cache, garbage
collection logic, recovery scheme, and logic to rate-limit
user I/Os versus garbage collection I/Os.
The L2P table is fully-associative and manages sectors at a
4KB granularity. Pblk stores the L2P table in two places, in
the out-of-band area of the media and on the last page of a
line. In the cause of a power failure, pblk will perform a
scan to recover the L2P table.
The user data is organized into lines. A line is data
striped across blocks and LUNs. The lines enable the host to
reduce the amount of metadata to maintain besides the user
data and makes it easier to implement RAID or erasure coding
in the future.
pblk implements multi-tenant support and can be instantiated
multiple times on the same drive. Each instance owns a
portion of the SSD - both regarding I/O bandwidth and
capacity - providing I/O isolation for each case.
Finally, pblk also exposes a sysfs interface that allows
user-space to peek into the internals of pblk. The interface
is available at /dev/block/*/pblk/ where * is the block
device name exposed.
This work also contains contributions from:
Matias Bjørling <matias@cnexlabs.com>
Simon A. F. Lund <slund@cnexlabs.com>
Young Tack Jin <youngtack.jin@gmail.com>
Huaicheng Li <huaicheng@cs.uchicago.edu>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <matias@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Conflicts were simply overlapping changes. In the net/ipv4/route.c
case the code had simply moved around a little bit and the same fix
was made in both 'net' and 'net-next'.
In the net/sched/sch_generic.c case a fix in 'net' happened at
the same time that a new argument was added to qdisc_hash_add().
Signed-off-by: David S. Miller <davem@davemloft.net>
