Fix checkpatch.pl error:
ERROR: space prohibited before open square bracket '['.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Trivial fix to spelling mistakes in ata_parse_force_one().
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

AXI master interface in CEVA AHCI controller requires two unique
Write/Read ID tags per port. This is because, ahci controller uses
different AXI ID[3:0] bits for identifying non-data transfers(like
reading descriptors, updating PRD tables, etc) and data transfers
(like sending/receiving FIS).To make SMMU work with SATA we need to
add correct SMMU stream id for SATA. SMMU stream id for SATA is
determined based on the AXI ID[1:0] as shown below

	SATA SMMU ID =  <TBU number>, 0011, 00, 00, AXI ID[1:0]
	Note: SATA in  ZynqMp uses TBU1 so TBU number = 0x1, so
	      SMMU ID = 001, 0011, 00, 00, AXI ID[1:0]

Since we have four different AXI ID[3:0] (2 for port0 & 2 for port1
as said above) we get four different SMMU stream id's combinations
for SATA. These AXI ID can be configured using PAXIC register.
In this patch we assumed the below AXI ID values

 Read ID/ Write ID for Non-Data Port0 transfers = 0
 Read ID/ Write ID for Data Port0 transfers = 1
 Read ID/ Write ID for Non-Data Port1 transfers = 2
 Read ID/ Write ID for Data Port1 transfers = 3

Based on the above values,SMMU stream ID's for SATA will be 0x4c0 &
0x4c1 for PORT0, 0x4c2 & 0x4c3 for PORT1. These values needed to be
added to iommus dts property. This patch does the same.
Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

The present suspend code disables the port interrupts
and stops the HBA. On resume it enables the interrupts and HBA.
This works fine until the FPD power domain is not off.
If FPD is off then the ceva vendor specific configurations like
OOB, AXI settings are lost, they need to be re-programmed and
also since SERDES is also in FPD , SATA lane phy init needs to
be called again (which is not happening in the present sequence)
Because of this incorrect sequence SATA fails to work on resume.

This patch corrects the code to make Suspend & Resume work in normal
and FPD off cases.
Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Reviewed-by: Shubhrajyoti Datta <shubhraj@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Previously PAXIC register was programmed before configuring PCFG
register. PCFG should be programmed with the address of the port
for which PAXIC should be configured for.
This was not happening before, so only one port PAXIC was written
correctly and the other port was having wrong value.
This patch moves the PXAIC register write after configuring PCFG,
doing so will correct the axi bus settings for sata port0 & port1.
Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

This patch adds support for CCI in SATA controller if CCI is
enabled in design. This patch will add CCI settings for SATA
if "dma-coherent" dts property is added.
Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

This patch updates the driver to make Rx Fifo water mark value
as a module parameter.
Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Since CEVA controller does not support Device Sleep capability,
we need to clear that feature by clearing the DEVSLP bit in word78
of IDENTIFY DEVICE data. This patch does the same.
Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

This patch sets gen 3 mode as default mode in ahci_ceva driver.
Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

In SATA Speed negotiation happens with  OOB(Out of Band) signals. These OOB
signal timing values are configured through vendor specific registers in the
SATA controller. These OOB timings depends on the generator and detector clock
frequency, which varies from board to board (ex: ep108 and zc1751 has different
clock frequencies).
To avoid maintaing these OOB settings in the driver, it is better to move these
settings to the device-tree node and read from the device-tree.

This patch does the same.
Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

This patch adds device tree bindings for sata port phy parameters
in the ahci-ceva.txt file.
Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

In cases where a "drop through" comment was already in place, I replaced
it  with a proper "fall through" comment, which is what GCC is expecting
to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

The pointer ehi is being assigned to a value that is never read
and is redundant.  Clean up the code and move the ehi declaration
and initialization to the code block where it is used. Cleans up
clang warning: Value stored to 'ehi' is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

This patch adds support for Cavium's fifth generation SATA controller.
It is an on-chip controller and complies with AHCI 1.3.1. As the
controller uses 64-bit addresses it cannot use the standard AHCI BAR5
and so uses BAR4.
Signed-off-by: Radha Mohan Chintakuntla <rchintakuntla@cavium.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Use the of_device_get_match_data() helper instead of open coding.
Note that the sata_rcar driver is used with DT only, so there's always a
valid match.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Make this const as it is only stored in the const field of a device
structure. Make the declaration in header const too.

Structure found using Coccinelle and changes done by hand.
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Don't populate const arrayis on the stack, instead make them static.
Makes the object code smaller by over 260 bytes:

Before:
   text	   data	    bss	    dec	    hex	filename
  64864	   5948	   4128	  74940	  124bc	drivers/ata/libata-scsi.o

After:
   text	   data	    bss	    dec	    hex	filename
  64183	   6364	   4128	  74675	  123b3	drivers/ata/libata-scsi.o
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

pio is initialized and the data is never read, instead it is almost
immediately being updated to a new value. Fix this by removing the
initialization.

Detected by scan-build:
"warning: Value stored to 'pio' during its initialization is never read"

Fixes: 669a5db4 ("[libata] Add a bunch of PATA drivers")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

As described by Matthew Garret quite a while back:
https://mjg59.dreamwidth.org/34868.html

Intel CPUs starting with the Haswell generation need SATA links to power
down for the "package" part of the CPU to reach low power-states like
PC7 / P8 which bring a significant power-saving with them.

The default max_performance lpm policy does not allow for these high
PC states, both the medium_power and min_power policies do allow this.

The min_power policy saves significantly more power, but there are some
reports of some disks / SSDs not liking min_power leading to system
crashes and in some cases even data corruption has been reported.

Matthew has found a document documenting the default settings of
Intel's IRST Windows driver with which most laptops ship:
https://www-ssl.intel.com/content/dam/doc/reference-guide/sata-devices-implementation-recommendations.pdf

Matthew wrote a patch changing med_power to match those defaults, but
that never got anywhere as some people where reporting issues with the
patch-set that patch was a part of.

This commit is another attempt to make the default IRST driver settings
available under Linux, but instead of changing medium_power and
potentially introducing regressions, this commit adds a new
med_power_with_dipm setting which is identical to the existing
medium_power accept that it enables dipm on top, which makes it match
the Windows IRST driver settings, which should hopefully be safe to
use on most devices.

The med_power_with_dipm setting is close to min_power, except that:
a) It does not use host-initiated slumber mode (ASP not set),
   but it does allow device-initiated slumber
b) It does not enable DevSlp mode

On my T440s test laptop I get the following power savings when idle:
medium_power		0.9W
med_power_with_dipm	1.2W
min_power		1.2W
Suggested-by: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

gcc-7 warns about the result of a constant multiplication used as
a boolean:

drivers/ata/libata-core.c: In function 'ata_timing_quantize':
drivers/ata/libata-core.c:3164:30: warning: '*' in boolean context, suggest '&&' instead [-Wint-in-bool-context]

This slightly rearranges the macro to simplify the code and avoid
the warning at the same time.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tejun Heo <tj@kernel.org>

Pull media updates from Mauro Carvalho Chehab:
 "Brazil's Independence Day pull request :-)

  This is one of the biggest media pull requests, with 625 patches
  affecting almost all parts of media (RC, DVB, V4L2, CEC, docs).

  This contains:

   - A lot of new drivers:
     * DVB frontends: mxl5xx, stv0910, stv6111;
     * camera flash: as3645a led driver;
     * HDMI receiver: adv748X;
     * camera sensor: Omnivision 6650 5M driver (ov6650);
     * HDMI CEC: ao-cec meson driver;
     * V4L2: Qualcom camss driver;
     * Remote controller: gpio-ir-tx, pwm-ir-tx and zx-irdec drivers.

   - The DDbridge DVB driver got a massive update, with makes it in sync
     with modern hardware from that vendor;

   - There's an important milestone on this series: the DVB
     documentation was written in 2003, but only started to be updated
     in 2007. It also used to contain several gaps from the time it was
     kept out of tree, mentioning error codes and device nodes that
     never existed upstream. On this series, it received a massive
     update: all non-deprecated digital TV APIs are now in sync with the
     current implementation;

   - Some DVB APIs that aren't used by any upstream driver got removed;

   - Other parts of the media documentation algo got updated, fixing
     some bugs on its PDF output and making it compatible with Sphinx
     version 1.6.

     As the number of hacks required to build PDF output reduced, I hope
     we'll have less troubles as newer versions of our documentation
     toolchain are released (famous last words);

   - As usual, lots of driver cleanups and improvements"

* tag 'media/v4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (624 commits)
  media: leds: as3645a: add V4L2_FLASH_LED_CLASS dependency
  media: get rid of removed DMX_GET_CAPS and DMX_SET_SOURCE leftovers
  media: Revert "[media] v4l: async: make v4l2 coexist with devicetree nodes in a dt overlay"
  media: staging: atomisp: sh_css_calloc shall return a pointer to the allocated space
  media: Revert "[media] lirc_dev: remove superfluous get/put_device() calls"
  media: add qcom_camss.rst to v4l-drivers rst file
  media: dvb headers: make checkpatch happier
  media: dvb uapi: move frontend legacy API to another part of the book
  media: pixfmt-srggb12p.rst: better format the table for PDF output
  media: docs-rst: media: Don't use \small for V4L2_PIX_FMT_SRGGB10 documentation
  media: index.rst: don't write "Contents:" on PDF output
  media: pixfmt*.rst: replace a two dots by a comma
  media: vidioc-g-fmt.rst: adjust table format
  media: vivid.rst: add a blank line to correct ReST format
  media: v4l2 uapi book: get rid of driver programming's chapter
  media: format.rst: use the right markup for important notes
  media: docs-rst: cardlists: change their format to flat-tables
  media: em28xx-cardlist.rst: update to reflect last changes
  media: v4l2-event.rst: adjust table to fit on PDF output
  media: docs: don't show ToC for each part on PDF output
  ...

Pull sound updates from Takashi Iwai:
 "We have touched quite a lot of files but with fewer changes at this
  cycle; as you can see, most of changes are trivial fixes, especially
  constification patches.

  Among the massive attacks by constification gangs, we had a few core
  changes (mostly for ASoC core), as well the fixes and the updates by
  major vendors.

  Some highlights:

  ALSA core:

   - Fix possible races in control API user-TLV codes

   - Small cleanup of PCM core

  ASoC:

   - Continued work for componentization; still half-baked, but we're
     certainly progressing

   - Use of devres for jack detection GPIOs, rather as a cleanup

   - Jack detection support for Qualcomm MSM8916

   - Support for Allwinner H3, Cirrus Logic CS43130, Intel Kabylake
     systems with RT5663, Realtek RT274, TI TLV320AIC32x6 and Wolfson
     WM8523"

* tag 'sound-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (512 commits)
  ALSA: hda/ca0132 - Fix memory leak at error path
  ALSA: hda: Fix forget to free resource in error handling code path in hda_codec_driver_probe
  ASoC: cs43130: Fix unused compiler warnings for PM runtime
  ASoC: cs43130: Fix possible Oops with invalid dev_id
  ASoC: cs43130: fix spelling mistake: "irq_occurrance" -> "irq_occurrence"
  ALSA: atmel: Remove leftovers of AVR32 removal
  ALSA: atmel: convert AC97c driver to GPIO descriptor API
  ALSA: hda/realtek - Enable jack detection function for Intel ALC700
  ALSA: hda: Fix regression of hdmi eld control created based on invalid pcm
  ASoC: Intel: Skylake: Add IPC to configure the copier secondary pins
  ASoC: add missing compile rule for max98371
  ASoC: add missing compile rule for sirf-audio-codec
  ASoC: add missing compile rule for max98371
  ASoC: cs43130: Add devicetree bindings for CS43130
  ASoC: cs43130: Add support for CS43130 codec
  ASoC: make clock direction configurable in asoc-simple
  ALSA: ctxfi: Remove null check before kfree
  ASoC: max98927: Changed device property read function
  ASoC: max98927: Modified DAPM widget and map to enable/disable VI sense path
  ASoC: max98927: Added PM suspend and resume function
  ...

Pull MD updates from Shaohua Li:
 "This update mainly fixes bugs:

   - Make raid5 ppl support several ppl from Pawel

   - Several raid5-cache bug fixes from Song

   - Bitmap fixes from Neil and Me

   - One raid1/10 regression fix since 4.12 from Me

   - Other small fixes and cleanup"

* tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
  md/bitmap: disable bitmap_resize for file-backed bitmaps.
  raid5-ppl: Recovery support for multiple partial parity logs
  md: Runtime support for multiple ppls
  md/raid0: attach correct cgroup info in bio
  lib/raid6: align AVX512 constants to 512 bits, not bytes
  raid5: remove raid5_build_block
  md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_show
  md: replace seq_release_private with seq_release
  md: notify about new spare disk in the container
  md/raid1/10: reset bio allocated from mempool
  md/raid5: release/flush io in raid5_do_work()
  md/bitmap: copy correct data for bitmap super

Pull MMC updates from Ulf Hansson:
 "MMC core:
   - Continue to refactor the mmc block code to prepare for blkmq
   - Move mmc block debugfs into block module
   - Next step for eMMC CMDQ by adding a new mmc host interface for it
   - Move Kconfig option MMC_DEBUG from core to host
   - Some additional minor improvements

  MMC host:
   - Declare structs as const when applicable
   - Explicitly request exclusive reset control when applicable
   - Improve some error paths and other various cleanups
   - sdhci: Preparations to support SDHCI OMAP
   - sdhci: Improve some PM related code
   - sdhci: Re-factoring and modernizations
   - sdhci-xenon: Add runtime PM and system sleep support
   - sdhci-xenon: Add support for eMMC HS400 Enhanced Strobe
   - sdhci-cadence: Add system sleep support
   - sdhci-of-at91: Improve system sleep support
   - dw_mmc: Add support for Hisilicon hi3660
   - sunxi: Add support for A83T eMMC
   - sunxi: Add support for DDR52 mode
   - meson-gx: Add support for UHS-I SD-cards
   - meson-gx: Cleanups and improvements
   - tmio: Fix CMD12 (STOP) handling
   - tmio: Cleanups and improvements
   - renesas_sdhi: Add r8a7743/5 support
   - renesas-sdhi: Add support for R-Car Gen3 SDHI DMAC
   - renesas_sdhi: Cleanups and improvements"

* tag 'mmc-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc: (145 commits)
  mmc: renesas_sdhi: Add r8a7743/5 support
  mmc: meson-gx: fix __ffsdi2 undefined on arm32
  mmc: sdhci-xenon: add runtime pm support and reimplement standby
  mmc: core: Move mmc_start_areq() declaration
  mmc: mmci: stop building qcom dml as module
  mmc: sunxi: Reset the device at probe time
  clk: sunxi-ng: Provide a default reset hook
  mmc: meson-gx: rework tuning function
  mmc: meson-gx: change default tx phase
  mmc: meson-gx: implement voltage switch callback
  mmc: meson-gx: use CCF to handle the clock phases
  mmc: meson-gx: implement card_busy callback
  mmc: meson-gx: simplify interrupt handler
  mmc: meson-gx: work around clk-stop issue
  mmc: meson-gx: fix dual data rate mode frequencies
  mmc: meson-gx: rework clock init function
  mmc: meson-gx: rework clk_set function
  mmc: meson-gx: rework set_ios function
  mmc: meson-gx: cfg init overwrite values
  mmc: meson-gx: initialize sane clk default before clock register
  ...

Pull block layer updates from Jens Axboe:
 "This is the first pull request for 4.14, containing most of the code
  changes. It's a quiet series this round, which I think we needed after
  the churn of the last few series. This contains:

   - Fix for a registration race in loop, from Anton Volkov.

   - Overflow complaint fix from Arnd for DAC960.

   - Series of drbd changes from the usual suspects.

   - Conversion of the stec/skd driver to blk-mq. From Bart.

   - A few BFQ improvements/fixes from Paolo.

   - CFQ improvement from Ritesh, allowing idling for group idle.

   - A few fixes found by Dan's smatch, courtesy of Dan.

   - A warning fixup for a race between changing the IO scheduler and
     device remova. From David Jeffery.

   - A few nbd fixes from Josef.

   - Support for cgroup info in blktrace, from Shaohua.

   - Also from Shaohua, new features in the null_blk driver to allow it
     to actually hold data, among other things.

   - Various corner cases and error handling fixes from Weiping Zhang.

   - Improvements to the IO stats tracking for blk-mq from me. Can
     drastically improve performance for fast devices and/or big
     machines.

   - Series from Christoph removing bi_bdev as being needed for IO
     submission, in preparation for nvme multipathing code.

   - Series from Bart, including various cleanups and fixes for switch
     fall through case complaints"

* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
  kernfs: checking for IS_ERR() instead of NULL
  drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
  drbd: Fix allyesconfig build, fix recent commit
  drbd: switch from kmalloc() to kmalloc_array()
  drbd: abort drbd_start_resync if there is no connection
  drbd: move global variables to drbd namespace and make some static
  drbd: rename "usermode_helper" to "drbd_usermode_helper"
  drbd: fix race between handshake and admin disconnect/down
  drbd: fix potential deadlock when trying to detach during handshake
  drbd: A single dot should be put into a sequence.
  drbd: fix rmmod cleanup, remove _all_ debugfs entries
  drbd: Use setup_timer() instead of init_timer() to simplify the code.
  drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
  drbd: new disk-option disable-write-same
  drbd: Fix resource role for newly created resources in events2
  drbd: mark symbols static where possible
  drbd: Send P_NEG_ACK upon write error in protocol != C
  drbd: add explicit plugging when submitting batches
  drbd: change list_for_each_safe to while(list_first_entry_or_null)
  drbd: introduce drbd_recv_header_maybe_unplug
  ...

Pull xen updates from Juergen Gross:

 - the new pvcalls backend for routing socket calls from a guest to dom0

 - some cleanups of Xen code

 - a fix for wrong usage of {get,put}_cpu()

* tag 'for-linus-4.14b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (27 commits)
  xen/mmu: set MMU_NORMAL_PT_UPDATE in remap_area_mfn_pte_fn
  xen: Don't try to call xen_alloc_p2m_entry() on autotranslating guests
  xen/events: events_fifo: Don't use {get,put}_cpu() in xen_evtchn_fifo_init()
  xen/pvcalls: use WARN_ON(1) instead of __WARN()
  xen: remove not used trace functions
  xen: remove unused function xen_set_domain_pte()
  xen: remove tests for pvh mode in pure pv paths
  xen-platform: constify pci_device_id.
  xen: cleanup xen.h
  xen: introduce a Kconfig option to enable the pvcalls backend
  xen/pvcalls: implement write
  xen/pvcalls: implement read
  xen/pvcalls: implement the ioworker functions
  xen/pvcalls: disconnect and module_exit
  xen/pvcalls: implement release command
  xen/pvcalls: implement poll command
  xen/pvcalls: implement accept command
  xen/pvcalls: implement listen command
  xen/pvcalls: implement bind command
  xen/pvcalls: implement connect command
  ...

Pull powerpc updates from Michael Ellerman:
 "Nothing really major this release, despite quite a lot of activity.
  Just lots of things all over the place.

  Some things of note include:

   - Access via perf to a new type of PMU (IMC) on Power9, which can
     count both core events as well as nest unit events (Memory
     controller etc).

   - Optimisations to the radix MMU TLB flushing, mostly to avoid
     unnecessary Page Walk Cache (PWC) flushes when the structure of the
     tree is not changing.

   - Reworks/cleanups of do_page_fault() to modernise it and bring it
     closer to other architectures where possible.

   - Rework of our page table walking so that THP updates only need to
     send IPIs to CPUs where the affected mm has run, rather than all
     CPUs.

   - The size of our vmalloc area is increased to 56T on 64-bit hash MMU
     systems. This avoids problems with the percpu allocator on systems
     with very sparse NUMA layouts.

   - STRICT_KERNEL_RWX support on PPC32.

   - A new sched domain topology for Power9, to capture the fact that
     pairs of cores may share an L2 cache.

   - Power9 support for VAS, which is a new mechanism for accessing
     coprocessors, and initial support for using it with the NX
     compression accelerator.

   - Major work on the instruction emulation support, adding support for
     many new instructions, and reworking it so it can be used to
     implement the emulation needed to fixup alignment faults.

   - Support for guests under PowerVM to use the Power9 XIVE interrupt
     controller.

  And probably that many things again that are almost as interesting,
  but I had to keep the list short. Plus the usual fixes and cleanups as
  always.

  Thanks to: Alexey Kardashevskiy, Alistair Popple, Andreas Schwab,
  Aneesh Kumar K.V, Anju T Sudhakar, Arvind Yadav, Balbir Singh,
  Benjamin Herrenschmidt, Bhumika Goyal, Breno Leitao, Bryant G. Ly,
  Christophe Leroy, Cédric Le Goater, Dan Carpenter, Dou Liyang,
  Frederic Barrat, Gautham R. Shenoy, Geliang Tang, Geoff Levand, Hannes
  Reinecke, Haren Myneni, Ivan Mikhaylov, John Allen, Julia Lawall,
  LABBE Corentin, Laurentiu Tudor, Madhavan Srinivasan, Markus Elfring,
  Masahiro Yamada, Matt Brown, Michael Neuling, Murilo Opsfelder Araujo,
  Nathan Fontenot, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran,
  Paul Mackerras, Rashmica Gupta, Rob Herring, Rui Teng, Sam Bobroff,
  Santosh Sivaraj, Scott Wood, Shilpasri G Bhat, Sukadev Bhattiprolu,
  Suraj Jitindar Singh, Tobin C. Harding, Victor Aoqui"

* tag 'powerpc-4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (321 commits)
  powerpc/xive: Fix section __init warning
  powerpc: Fix kernel crash in emulation of vector loads and stores
  powerpc/xive: improve debugging macros
  powerpc/xive: add XIVE Exploitation Mode to CAS
  powerpc/xive: introduce H_INT_ESB hcall
  powerpc/xive: add the HW IRQ number under xive_irq_data
  powerpc/xive: introduce xive_esb_write()
  powerpc/xive: rename xive_poke_esb() in xive_esb_read()
  powerpc/xive: guest exploitation of the XIVE interrupt controller
  powerpc/xive: introduce a common routine xive_queue_page_alloc()
  powerpc/sstep: Avoid used uninitialized error
  axonram: Return directly after a failed kzalloc() in axon_ram_probe()
  axonram: Improve a size determination in axon_ram_probe()
  axonram: Delete an error message for a failed memory allocation in axon_ram_probe()
  powerpc/powernv/npu: Move tlb flush before launching ATSD
  powerpc/macintosh: constify wf_sensor_ops structures
  powerpc/iommu: Use permission-specific DEVICE_ATTR variants
  powerpc/eeh: Delete an error out of memory message at init time
  powerpc/mm: Use seq_putc() in two functions
  macintosh: Convert to using %pOF instead of full_name
  ...

Pull EFI updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Transparently fall back to other poweroff method(s) if EFI poweroff
     fails (and returns)

   - Use separate PE/COFF section headers for the RX and RW parts of the
     ARM stub loader so that the firmware can use strict mapping
     permissions

   - Add support for requesting the firmware to wipe RAM at warm reboot

   - Increase the size of the random seed obtained from UEFI so CRNG
     fast init can complete earlier

   - Update the EFI framebuffer address if it points to a BAR that gets
     moved by the PCI resource allocation code

   - Enable "reset attack mitigation" of TPM environments: this is
     enabled if the kernel is configured with
     CONFIG_RESET_ATTACK_MITIGATION=y.

   - Clang related fixes

   - Misc cleanups, constification, refactoring, etc"

* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi/bgrt: Use efi_mem_type()
  efi: Move efi_mem_type() to common code
  efi/reboot: Make function pointer orig_pm_power_off static
  efi/random: Increase size of firmware supplied randomness
  efi/libstub: Enable reset attack mitigation
  firmware/efi/esrt: Constify attribute_group structures
  firmware/efi: Constify attribute_group structures
  firmware/dcdbas: Constify attribute_group structures
  arm/efi: Split zImage code and data into separate PE/COFF sections
  arm/efi: Replace open coded constants with symbolic ones
  arm/efi: Remove pointless dummy .reloc section
  arm/efi: Remove forbidden values from the PE/COFF header
  drivers/fbdev/efifb: Allow BAR to be moved instead of claiming it
  efi/reboot: Fall back to original power-off method if EFI_RESET_SHUTDOWN returns
  efi/arm/arm64: Add missing assignment of efi.config_table
  efi/libstub/arm64: Set -fpie when building the EFI stub
  efi/libstub/arm64: Force 'hidden' visibility for section markers
  efi/libstub/arm64: Use hidden attribute for struct screen_info reference
  efi/arm: Don't mark ACPI reclaim memory as MEMBLOCK_NOMAP

Pull x86 platform updates from Ingo Molnar:
 "The main changes include various Hyper-V optimizations such as faster
  hypercalls and faster/better TLB flushes - and there's also some
  Intel-MID cleanups"

* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tracing/hyper-v: Trace hyperv_mmu_flush_tlb_others()
  x86/hyper-v: Support extended CPU ranges for TLB flush hypercalls
  x86/platform/intel-mid: Make several arrays static, to make code smaller
  MAINTAINERS: Add missed file for Hyper-V
  x86/hyper-v: Use hypercall for remote TLB flush
  hyper-v: Globalize vp_index
  x86/hyper-v: Implement rep hypercalls
  hyper-v: Use fast hypercall for HVCALL_SIGNAL_EVENT
  x86/hyper-v: Introduce fast hypercall implementation
  x86/hyper-v: Make hv_do_hypercall() inline
  x86/hyper-v: Include hyperv/ only when CONFIG_HYPERV is set
  x86/platform/intel-mid: Make 'bt_sfi_data' const
  x86/platform/intel-mid: Make IRQ allocation a bit more flexible
  x86/platform/intel-mid: Group timers callbacks together

Pull libata updates from Tejun Heo:
 "Except for the ahci fix that fixes a boot issue, nothing major in this
  pull request. Some new platform controller support and device specific
  changes"

* 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
  libata: zpodd: make arrays cdb static, reduces object code size
  ahci: don't use MSI for devices with the silly Intel NVMe remapping scheme
  dt-bindings: ata: add DT bindings for MediaTek SATA controller
  ata: mediatek: add support for MediaTek SATA controller
  pata_octeon_cf: use of_property_read_{bool|u32}()
  cs5536: add support for IDE controller variant
  ata: sata_gemini: Introduce explicit IDE pin control
  ata: sata_gemini: Retire custom pin control
  ata: ahci_platform: Add shutdown handler
  ata: sata_gemini: explicitly request exclusive reset control
  ata: Drop unnecessary static
  ata: Convert to using %pOF instead of full_name

Pull cgroup updates from Tejun Heo:
 "Several notable changes this cycle:

   - Thread mode was merged. This will be used for cgroup2 support for
     CPU and possibly other controllers. Unfortunately, CPU controller
     cgroup2 support didn't make this pull request but most contentions
     have been resolved and the support is likely to be merged before
     the next merge window.

   - cgroup.stat now shows the number of descendant cgroups.

   - cpuset now can enable the easier-to-configure v2 behavior on v1
     hierarchy"

* 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits)
  cpuset: Allow v2 behavior in v1 cgroup
  cgroup: Add mount flag to enable cpuset to use v2 behavior in v1 cgroup
  cgroup: remove unneeded checks
  cgroup: misc changes
  cgroup: short-circuit cset_cgroup_from_root() on the default hierarchy
  cgroup: re-use the parent pointer in cgroup_destroy_locked()
  cgroup: add cgroup.stat interface with basic hierarchy stats
  cgroup: implement hierarchy limits
  cgroup: keep track of number of descent cgroups
  cgroup: add comment to cgroup_enable_threaded()
  cgroup: remove unnecessary empty check when enabling threaded mode
  cgroup: update debug controller to print out thread mode information
  cgroup: implement cgroup v2 thread support
  cgroup: implement CSS_TASK_ITER_THREADED
  cgroup: introduce cgroup->dom_cgrp and threaded css_set handling
  cgroup: add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS
  cgroup: reorganize cgroup.procs / task write path
  cgroup: replace css_set walking populated test with testing cgrp->nr_populated_csets
  cgroup: distinguish local and children populated states
  cgroup: remove now unused list_head @pending in cgroup_apply_cftypes()
  ...

Pull workqueue updates from Tejun Heo:
 "Nothing major. I introduced a flag collsion bug during v4.13 cycle
  which is fixed in this pull request. Fortunately, the flag is for
  debugging / verification and the bug isn't critical"

* 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Fix flag collision
  workqueue: Use TASK_IDLE
  workqueue: fix path to documentation
  workqueue: doc change for ST behavior on NUMA systems

Pull percpu updates from Tejun Heo:
 "A lot of changes for percpu this time around. percpu inherited the
  same area allocator from the original pre-virtual-address-mapped
  implementation. This was from the time when percpu allocator wasn't
  used all that much and the implementation was focused on simplicity,
  with the unfortunate computational complexity of O(number of areas
  allocated from the chunk) per alloc / free.

  With the increase in percpu usage, we're hitting cases where the lack
  of scalability is hurting. The most prominent one right now is bpf
  perpcu map creation / destruction which may allocate and free a lot of
  entries consecutively and it's likely that the problem will become
  more prominent in the future.

  To address the issue, Dennis replaced the area allocator with hinted
  bitmap allocator which is more consistent. While the new allocator
  does perform a bit worse in some cases, it outperforms the old
  allocator way more than an order of magnitude in other more common
  scenarios while staying mostly flat in CPU overhead and completely
  flat in memory consumption"

* 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (27 commits)
  percpu: update header to contain bitmap allocator explanation.
  percpu: update pcpu_find_block_fit to use an iterator
  percpu: use metadata blocks to update the chunk contig hint
  percpu: update free path to take advantage of contig hints
  percpu: update alloc path to only scan if contig hints are broken
  percpu: keep track of the best offset for contig hints
  percpu: skip chunks if the alloc does not fit in the contig hint
  percpu: add first_bit to keep track of the first free in the bitmap
  percpu: introduce bitmap metadata blocks
  percpu: replace area map allocator with bitmap
  percpu: generalize bitmap (un)populated iterators
  percpu: increase minimum percpu allocation size and align first regions
  percpu: introduce nr_empty_pop_pages to help empty page accounting
  percpu: change the number of pages marked in the first_chunk pop bitmap
  percpu: combine percpu address checks
  percpu: modify base_addr to be region specific
  percpu: setup_first_chunk rename schunk/dchunk to chunk
  percpu: end chunk area maps page aligned for the populated bitmap
  percpu: unify allocation of schunk and dchunk
  percpu: setup_first_chunk remove dyn_size and consolidate logic
  ...

Merge updates from Andrew Morton:

 - various misc bits

 - DAX updates

 - OCFS2

 - most of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (119 commits)
  mm,fork: introduce MADV_WIPEONFORK
  x86,mpx: make mpx depend on x86-64 to free up VMA flag
  mm: add /proc/pid/smaps_rollup
  mm: hugetlb: clear target sub-page last when clearing huge page
  mm: oom: let oom_reap_task and exit_mmap run concurrently
  swap: choose swap device according to numa node
  mm: replace TIF_MEMDIE checks by tsk_is_oom_victim
  mm, oom: do not rely on TIF_MEMDIE for memory reserves access
  z3fold: use per-cpu unbuddied lists
  mm, swap: don't use VMA based swap readahead if HDD is used as swap
  mm, swap: add sysfs interface for VMA based swap readahead
  mm, swap: VMA based swap readahead
  mm, swap: fix swap readahead marking
  mm, swap: add swap readahead hit statistics
  mm/vmalloc.c: don't reinvent the wheel but use existing llist API
  mm/vmstat.c: fix wrong comment
  selftests/memfd: add memfd_create hugetlbfs selftest
  mm/shmem: add hugetlbfs support to memfd_create()
  mm, devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups
  mm/vmalloc.c: halve the number of comparisons performed in pcpu_get_vm_areas()
  ...

While debugging a problem, I thought that using
cr4_set_bits_and_update_boot() to restore CR4.PCIDE would be
helpful.  It turns out to be counterproductive.

Add a comment documenting how this works.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When Linux brings a CPU down and back up, it switches to init_mm and then
loads swapper_pg_dir into CR3.  With PCID enabled, this has the side effect
of masking off the ASID bits in CR3.

This can result in some confusion in the TLB handling code.  If we
bring a CPU down and back up with any ASID other than 0, we end up
with the wrong ASID active on the CPU after resume.  This could
cause our internal state to become corrupt, although major
corruption is unlikely because init_mm doesn't have any user pages.
More obviously, if CONFIG_DEBUG_VM=y, we'll trip over an assertion
in the next context switch.  The result of *that* is a failure to
resume from suspend with probability 1 - 1/6^(cpus-1).

Fix it by reinitializing cpu_tlbstate on resume and CPU bringup.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Jiri Kosina <jikos@kernel.org>
Fixes: 10af6235 ("x86/mm: Implement PCID based optimization: try to preserve old TLB entries using PCID")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Introduce MADV_WIPEONFORK semantics, which result in a VMA being empty
in the child process after fork.  This differs from MADV_DONTFORK in one
important way.

If a child process accesses memory that was MADV_WIPEONFORK, it will get
zeroes.  The address ranges are still valid, they are just empty.

If a child process accesses memory that was MADV_DONTFORK, it will get a
segmentation fault, since those address ranges are no longer valid in
the child after fork.

Since MADV_DONTFORK also seems to be used to allow very large programs
to fork in systems with strict memory overcommit restrictions, changing
the semantics of MADV_DONTFORK might break existing programs.

MADV_WIPEONFORK only works on private, anonymous VMAs.

The use case is libraries that store or cache information, and want to
know that they need to regenerate it in the child process after fork.

Examples of this would be:
 - systemd/pulseaudio API checks (fail after fork) (replacing a getpid
   check, which is too slow without a PID cache)
 - PKCS#11 API reinitialization check (mandated by specification)
 - glibc's upcoming PRNG (reseed after fork)
 - OpenSSL PRNG (reseed after fork)

The security benefits of a forking server having a re-inialized PRNG in
every child process are pretty obvious.  However, due to libraries
having all kinds of internal state, and programs getting compiled with
many different versions of each library, it is unreasonable to expect
calling programs to re-initialize everything manually after fork.

A further complication is the proliferation of clone flags, programs
bypassing glibc's functions to call clone directly, and programs calling
unshare, causing the glibc pthread_atfork hook to not get called.

It would be better to have the kernel take care of this automatically.

The patch also adds MADV_KEEPONFORK, to undo the effects of a prior
MADV_WIPEONFORK.

This is similar to the OpenBSD minherit syscall with MAP_INHERIT_ZERO:

    https://man.openbsd.org/minherit.2

[akpm@linux-foundation.org: numerically order arch/parisc/include/uapi/asm/mman.h #defines]
Link: http://lkml.kernel.org/r/20170811212829.29186-3-riel@redhat.comSigned-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Florian Weimer <fweimer@redhat.com>
Reported-by: Colm MacCártaigh <colm@allcosts.net>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "mm,fork,security: introduce MADV_WIPEONFORK", v4.

If a child process accesses memory that was MADV_WIPEONFORK, it will get
zeroes.  The address ranges are still valid, they are just empty.

If a child process accesses memory that was MADV_DONTFORK, it will get a
segmentation fault, since those address ranges are no longer valid in
the child after fork.

Since MADV_DONTFORK also seems to be used to allow very large programs
to fork in systems with strict memory overcommit restrictions, changing
the semantics of MADV_DONTFORK might break existing programs.

The use case is libraries that store or cache information, and want to
know that they need to regenerate it in the child process after fork.

Examples of this would be:
 - systemd/pulseaudio API checks (fail after fork) (replacing a getpid
   check, which is too slow without a PID cache)
 - PKCS#11 API reinitialization check (mandated by specification)
 - glibc's upcoming PRNG (reseed after fork)
 - OpenSSL PRNG (reseed after fork)

The security benefits of a forking server having a re-inialized PRNG in
every child process are pretty obvious.  However, due to libraries
having all kinds of internal state, and programs getting compiled with
many different versions of each library, it is unreasonable to expect
calling programs to re-initialize everything manually after fork.

A further complication is the proliferation of clone flags, programs
bypassing glibc's functions to call clone directly, and programs calling
unshare, causing the glibc pthread_atfork hook to not get called.

It would be better to have the kernel take care of this automatically.

The patchset also adds MADV_KEEPONFORK, to undo the effects of a prior
MADV_WIPEONFORK.

This is similar to the OpenBSD minherit syscall with MAP_INHERIT_ZERO:

    https://man.openbsd.org/minherit.2

This patch (of 2):

MPX only seems to be available on 64 bit CPUs, starting with Skylake and
Goldmont.  Move VM_MPX into the 64 bit only portion of vma->vm_flags, in
order to free up a VMA flag.

Link: http://lkml.kernel.org/r/20170811212829.29186-2-riel@redhat.comSigned-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Colm MacCártaigh <colm@allcosts.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

/proc/pid/smaps_rollup is a new proc file that improves the performance
of user programs that determine aggregate memory statistics (e.g., total
PSS) of a process.

Android regularly "samples" the memory usage of various processes in
order to balance its memory pool sizes.  This sampling process involves
opening /proc/pid/smaps and summing certain fields.  For very large
processes, sampling memory use this way can take several hundred
milliseconds, due mostly to the overhead of the seq_printf calls in
task_mmu.c.

smaps_rollup improves the situation.  It contains most of the fields of
/proc/pid/smaps, but instead of a set of fields for each VMA,
smaps_rollup instead contains one synthetic smaps-format entry
representing the whole process.  In the single smaps_rollup synthetic
entry, each field is the summation of the corresponding field in all of
the real-smaps VMAs.  Using a common format for smaps_rollup and smaps
allows userspace parsers to repurpose parsers meant for use with
non-rollup smaps for smaps_rollup, and it allows userspace to switch
between smaps_rollup and smaps at runtime (say, based on the
availability of smaps_rollup in a given kernel) with minimal fuss.

By using smaps_rollup instead of smaps, a caller can avoid the
significant overhead of formatting, reading, and parsing each of a large
process's potentially very numerous memory mappings.  For sampling
system_server's PSS in Android, we measured a 12x speedup, representing
a savings of several hundred milliseconds.

One alternative to a new per-process proc file would have been including
PSS information in /proc/pid/status.  We considered this option but
thought that PSS would be too expensive (by a few orders of magnitude)
to collect relative to what's already emitted as part of
/proc/pid/status, and slowing every user of /proc/pid/status for the
sake of readers that happen to want PSS feels wrong.

The code itself works by reusing the existing VMA-walking framework we
use for regular smaps generation and keeping the mem_size_stats
structure around between VMA walks instead of using a fresh one for each
VMA.  In this way, summation happens automatically.  We let seq_file
walk over the VMAs just as it does for regular smaps and just emit
nothing to the seq_file until we hit the last VMA.

Benchmarks:

    using smaps:
    iterations:1000 pid:1163 pss:220023808
    0m29.46s real 0m08.28s user 0m20.98s system

    using smaps_rollup:
    iterations:1000 pid:1163 pss:220702720
    0m04.39s real 0m00.03s user 0m04.31s system

We're using the PSS samples we collect asynchronously for
system-management tasks like fine-tuning oom_adj_score, memory use
tracking for debugging, application-level memory-use attribution, and
deciding whether we want to kill large processes during system idle
maintenance windows.  Android has been using PSS for these purposes for
a long time; as the average process VMA count has increased and and
devices become more efficiency-conscious, PSS-collection inefficiency
has started to matter more.  IMHO, it'd be a lot safer to optimize the
existing PSS-collection model, which has been fine-tuned over the years,
instead of changing the memory tracking approach entirely to work around
smaps-generation inefficiency.

Tim said:

: There are two main reasons why Android gathers PSS information:
:
: 1. Android devices can show the user the amount of memory used per
:    application via the settings app.  This is a less important use case.
:
: 2. We log PSS to help identify leaks in applications.  We have found
:    an enormous number of bugs (in the Android platform, in Google's own
:    apps, and in third-party applications) using this data.
:
: To do this, system_server (the main process in Android userspace) will
: sample the PSS of a process three seconds after it changes state (for
: example, app is launched and becomes the foreground application) and about
: every ten minutes after that.  The net result is that PSS collection is
: regularly running on at least one process in the system (usually a few
: times a minute while the screen is on, less when screen is off due to
: suspend).  PSS of a process is an incredibly useful stat to track, and we
: aren't going to get rid of it.  We've looked at some very hacky approaches
: using RSS ("take the RSS of the target process, subtract the RSS of the
: zygote process that is the parent of all Android apps") to reduce the
: accounting time, but it regularly overestimated the memory used by 20+
: percent.  Accordingly, I don't think that there's a good alternative to
: using PSS.
:
: We started looking into PSS collection performance after we noticed random
: frequency spikes while a phone's screen was off; occasionally, one of the
: CPU clusters would ramp to a high frequency because there was 200-300ms of
: constant CPU work from a single thread in the main Android userspace
: process.  The work causing the spike (which is reasonable governor
: behavior given the amount of CPU time needed) was always PSS collection.
: As a result, Android is burning more power than we should be on PSS
: collection.
:
: The other issue (and why I'm less sure about improving smaps as a
: long-term solution) is that the number of VMAs per process has increased
: significantly from release to release.  After trying to figure out why we
: were seeing these 200-300ms PSS collection times on Android O but had not
: noticed it in previous versions, we found that the number of VMAs in the
: main system process increased by 50% from Android N to Android O (from
: ~1800 to ~2700) and varying increases in every userspace process.  Android
: M to N also had an increase in the number of VMAs, although not as much.
: I'm not sure why this is increasing so much over time, but thinking about
: ASLR and ways to make ASLR better, I expect that this will continue to
: increase going forward.  I would not be surprised if we hit 5000 VMAs on
: the main Android process (system_server) by 2020.
:
: If we assume that the number of VMAs is going to increase over time, then
: doing anything we can do to reduce the overhead of each VMA during PSS
: collection seems like the right way to go, and that means outputting an
: aggregate statistic (to avoid whatever overhead there is per line in
: writing smaps and in reading each line from userspace).

Link: http://lkml.kernel.org/r/20170812022148.178293-1-dancol@google.comSigned-off-by: Daniel Colascione <dancol@google.com>
Cc: Tim Murray <timmurray@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sonny Rao <sonnyrao@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Huge page helps to reduce TLB miss rate, but it has higher cache
footprint, sometimes this may cause some issue.  For example, when
clearing huge page on x86_64 platform, the cache footprint is 2M.  But
on a Xeon E5 v3 2699 CPU, there are 18 cores, 36 threads, and only 45M
LLC (last level cache).  That is, in average, there are 2.5M LLC for
each core and 1.25M LLC for each thread.

If the cache pressure is heavy when clearing the huge page, and we clear
the huge page from the begin to the end, it is possible that the begin
of huge page is evicted from the cache after we finishing clearing the
end of the huge page.  And it is possible for the application to access
the begin of the huge page after clearing the huge page.

To help the above situation, in this patch, when we clear a huge page,
the order to clear sub-pages is changed.  In quite some situation, we
can get the address that the application will access after we clear the
huge page, for example, in a page fault handler.  Instead of clearing
the huge page from begin to end, we will clear the sub-pages farthest
from the the sub-page to access firstly, and clear the sub-page to
access last.  This will make the sub-page to access most cache-hot and
sub-pages around it more cache-hot too.  If we cannot know the address
the application will access, the begin of the huge page is assumed to be
the the address the application will access.

With this patch, the throughput increases ~28.3% in vm-scalability
anon-w-seq test case with 72 processes on a 2 socket Xeon E5 v3 2699
system (36 cores, 72 threads).  The test case creates 72 processes, each
process mmap a big anonymous memory area and writes to it from the begin
to the end.  For each process, other processes could be seen as other
workload which generates heavy cache pressure.  At the same time, the
cache miss rate reduced from ~33.4% to ~31.7%, the IPC (instruction per
cycle) increased from 0.56 to 0.74, and the time spent in user space is
reduced ~7.9%

Christopher Lameter suggests to clear bytes inside a sub-page from end
to begin too.  But tests show no visible performance difference in the
tests.  May because the size of page is small compared with the cache
size.

Thanks Andi Kleen to propose to use address to access to determine the
order of sub-pages to clear.

The hugetlbfs access address could be improved, will do that in another
patch.

[ying.huang@intel.com: improve readability of clear_huge_page()]
  Link: http://lkml.kernel.org/r/20170830051842.1397-1-ying.huang@intel.com
Link: http://lkml.kernel.org/r/20170815014618.15842-1-ying.huang@intel.comSuggested-by: Andi Kleen <andi.kleen@intel.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Jan Kara <jack@suse.cz>
Reviewed-by: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Nadia Yvette Chambers <nyc@holomorphy.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shaohua Li <shli@fb.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>