Pull gfs2 updates from Steven Whitehouse:
 "This time we have a couple of bug fixes, one relating to bad i_goal
  values which are now ignored (i_goal is basically a hint so it is safe
  to so this) and another relating to the saving of the dirent location
  during rename.

  There is one performance improvement, which is an optimisation in
  rgblk_free so that multiple block deallocations will now be more
  efficient, and one clean up patch to use _RET_IP_ rather than writing
  it out longhand"

* tag 'gfs2-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
  GFS2: use _RET_IP_ instead of (unsigned long)__builtin_return_address(0)
  GFS2: Use gfs2_rbm_incr in rgblk_free
  GFS2: Make rename not save dirent location
  GFS2: fix bad inode i_goal values during block allocation

Pull VFIO updates from Alex Williamson:
 - Nested IOMMU extension to type1 (Will Deacon)
 - Restore MSIx message before enabling (Gavin Shan)
 - Fix remove path locking (Alex Williamson)

* tag 'vfio-v3.18-rc1' of git://github.com/awilliam/linux-vfio:
  vfio-pci: Fix remove path locking
  drivers/vfio: Export vfio_spapr_iommu_eeh_ioctl() with GPL
  vfio/pci: Restore MSIx message prior to enabling
  PCI: Export MSI message relevant functions
  vfio/iommu_type1: add new VFIO_TYPE1_NESTING_IOMMU IOMMU type
  iommu: introduce domain attribute for nesting IOMMUs

Pull devicetree changes from Grant Likely:
 "This branch contains bug fixes and new features for the devicetree
  code.

  Most of the changes are either new testcases for the selftest code or
  documentation changes.  The most notable change is the addition of a
  phandle resolver for use when grafting in a second device tree blob
  into the core tree.  The resolver isn't currently used by anything
  other than the selftest module, but it will be used to support device
  tree overlays; probably in the v3.19 timeframe.

  Also note that I've moved my normal tree from git.secretlab.ca to
  git.kernel.org"

* tag 'devicetree-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/glikely/linux:
  of/selftest: Move hash table off stack to fix large frame size
  To remove non-ascii characters in of_selftest.txt
  of/selftest: Use the resolver to fixup phandles
  of: Introduce Device Tree resolve support.
  of/selftest: Add a test for duplicate phandles
  of: Don't try to search when phandle == 0
  of/selftest: Test structure of device tree
  of: Fix NULL dereference in selftest removal code
  of: add vendor prefix for Chipidea
  of: Add vendor prefix for Innolux Corporation
  of: Add vendor prefix for Sitronix
  devicetree: bindings: Document Gateworks vendor prefix
  of: Add vendor prefix for Energy Micro
  dt/documentation: add specification of dma bus information

Pull backlight driver updates from Lee Jones:
 "Changes to existing drivers:
   - Checkpatch fixes
   - Removal of unused code in generic_bl
   - Removal of superfluous .owner attribute

  No new or removed drivers/supported devices"

* tag 'backlight-for-linus-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: omap1: add blank line after declarations
  backlight: jornada720: Remove 'else' after a return
  backlight: jornada720: Remove 'else' after a return
  backlight: wm831x_bl: Add blank line after declarations
  backlight: tdo24m: Add blank line after declarations
  backlight: s6e63m0: Remove 'else' after a return
  backlight: pcf50633: Add blank line after declarations
  backlight: lp855x: Add blank line after declarations
  backlight: lms501kf03: Remove 'else' after a return
  backlight: lm3639: Remove unnecessary return statements
  backlight: ld9040: Remove 'else' after a return
  backlight: ili922x: Remove 'else' after a return
  backlight: cr_bllcd: Add blank line after declarations
  backlight: corgi_lcd: Add blank line after declarations
  backlight: ams369fg06: Remove 'else' after a return
  backlight: adp8870: Add blank line after declarations
  backlight: adp8860: Add blank line after declarations
  backlight: adp5520: Add blank line after declarations
  backlight: generic_bl: Remove unused function
  backlight: Remove .owner field for drivers using module_platform_driver

Pull MMC updates from Ulf Hansson:
 "MMC core:
   - Fix SDIO IRQ bug
   - MMC regulator improvements
   - Fix slot-gpio card detect bug
   - Add support for Driver Stage Register
   - Convert the common MMC OF parser to use GPIO descriptors
   - Convert MMC_CAP2_NO_MULTI_READ into a callback, ->multi_io_quirk()
   - Some additional minor fixes

  MMC host:
   - mmci: Support Qualcomm specific DML layer for DMA
   - dw_mmc: Use common MMC regulators
   - dw_mmc: Add support for Rock-chips RK3288
   - tmio: Enable runtime PM support
   - tmio: Add support for R-Car Gen2 SoCs
   - tmio: Several fixes and improvements
   - omap_hsmmc: Removed Balaji from MAINTAINERS
   - jz4740: add DMA and pre/post support
   - sdhci: Add support for Intel Braswell
   - sdhci: Several fixes and improvements"

* tag 'mmc-v3.18-1' of git://git.linaro.org/people/ulf.hansson/mmc: (119 commits)
  ARM: dts: fix MMC2 regulators for Exynos5420 Arndale Octa board
  mmc: sdhci-acpi: Fix Braswell eMMC timeout clock frequency
  mmc: sdhci-acpi: Pass HID and UID to probe_slot
  mmc: sdhci-acpi: Get UID directly from acpi_device
  mmc, sdhci, bcm-kona, LLVMLinux: Remove use of __initconst
  mmc: sdhci-pci: Fix Braswell eMMC timeout clock frequency
  mmc: sdhci: Let a driver override timeout clock frequency
  mmc: sdhci-pci: Add Bay Trail and Braswell SD card detect
  mmc: sdhci-pci: Set SDHCI_QUIRK2_STOP_WITH_TC for Intel BYT host controllers
  mmc: sdhci-acpi: Add a HID and UID for a SD Card host controller
  mmc: sdhci-acpi: Set SDHCI_QUIRK2_STOP_WITH_TC for Intel host controllers
  mmc: sdhci: Add quirk for always getting TC with stop cmd
  mmc: core: restore detect line inversion semantics
  mmc: Fix incorrect warning when setting 0 Hz via debugfs
  mmc: Fix use of wrong device in mmc_gpiod_free_cd()
  mmc: atmel-mci: fix mismatched section on atmci_cleanup_slot
  mmc: rtsx_pci: Set power related cap2 macros
  mmc: core: Add new power_mode MMC_POWER_UNDEFINED
  mmc: sdhci: execute tuning when device is not busy
  mmc: atmel-mci: Release mmc resources on failure in probe
  ..

Pull sound updates from Takashi Iwai:
 "This time it's a relatively calm update batch, but the amount isn't
  too small in the end.  Here we go over some highlights:

  ALSA core:
   - One major change is the support of nonatomic PCM operations.  This
     allows the trigger and other callbacks to call schedule(), which
     would be useful for mailbox type communications.  Already some
     drivers (Digigram ones) have been converted to use together with
     threaded irqs as an example.
   - Improvement / fixes of DSD PCM format support

  HD-audio:
   - Large volume of rewrites are found in Realtek codec driver for
     converting Dell and HP quirks to generic forms.
   - Inverted dmic code cleanup from David.
   - Realtek COEF access has been optimized.
   - Now HD-audio jack infrastructure allows multiple callbacks, which
     fixes / simplifies the jack-dependent power controls on STAC/IDT
     and VIA codecs.
   - Many additional device-specific fixups as usual
   - A few deadcode cleanups, CA0132 code cleanup, etc.

  ASoC:
   - More componentization work from Lars-Peter, this time mainly
     cleaning up the suspend and bias level transition callbacks.
   - Real system support for the Intel drivers and a bunch of fixes and
     enhancements for the associated CODEC drivers, this is going to
     need a lot quirks over time due to the lack of any firmware
     description of the boards.
   - Jack detect support for simple card from Dylan Reid.
   - A bunch of small fixes and enhancements for the Freescale drivers.
   - New drivers for Analog Devices SSM4567, Cirrus Logic CS35L32,
     Everest Semiconductor ES8328 and Freescale cards using the ASRC in
     newer i.MX processors.
   - A few simple-card fixes, mostly cleanups but also a fix for
     interaction between GPIO 0 and simple-card.

  Misc:
   - Virtuoso / Oxygen updates by Clemens
   - USB-audio: Yamaha MOTIF XF MIDI port name fixes
   - Conversion of kernel messages to standard dev_*() in ctxfi driver"

* tag 'sound-3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (251 commits)
  ASoC: mc13783: Ensure we only try to dereference valid of_nodes
  ASoC: rockchip-i2s: fix infinite loop in rockchip_snd_txctrl
  ALSA: hda - Add dock port support to Thinkpad L440 (71aa:501e)
  ALSA: Allow pass NULL dev for snd_pci_quirk_lookup()
  ASoC: imx-es8328: Fix of_node_put() call with uninitialized object
  ASoC: soc-pcm: fix sig_bits determination in soc_pcm_apply_msb()
  ASoC: simple-card: Initialize headphone and mic GPIO numbers
  ASoC: imx-es8328: Fix missing return code in imx_es8328_probe()
  ALSA: hda - Add dock support for Thinkpad T440 (17aa:2212)
  ALSA: usb: caiaq: check for cdev->n_streams > 1
  ASoC: 88pm860x-codec: Fix possibly missing string termination
  ASoC: core: fix use after free in snd_soc_remove_platform()
  ASoC: soc-dapm: fix use after free
  ALSA: hda - Make the inv dmic handling for Realtek use generic parser
  ALSA: hda - Add Inverted Internal mic for Samsung Ativ book 9 (NP900X3G)
  ALSA: hda - Add inverted internal mic for Asus Aspire 4830T
  ASoC: Intel: byt-rt5640: fix coccinelle warnings
  ASoC: fsl_esai doc: Add "fsl,vf610-esai" as compatible string
  ASoC: da732x: Remove unnecessary KERN_ERR in pr_err()
  ASoC: simple-card: Fix detect gpio documentation.
  ...

Pull edac updates from Mauro Carvalho Chehab:
 "Nothing really exiting here: just one bug fix at sb_edac, and some
  changes to allow other drivers to use some shared PCI addresses"

* tag 'edac/v3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-edac:
  sb_edac: Claim a different PCI device
  Move Intel SNB device ids from sb_edac to pci_ids.h
  sb_edac: avoid INTERNAL ERROR message in EDAC with unspecified channel

Pull media updates from Mauro Carvalho Chehab:

 - new IR driver: hix5hd2-ir

 - the virtual test driver (vivi) was replaced by vivid, with has an
   almost complete set of features to emulate most v4l2 devices and
   properly test all sorts of userspace apps

 - the as102 driver had several bugs fixed and was properly split into a
   frontend and a core driver.  With that, it got promoted from staging
   into mainstream

 - one new CI driver got added for CIMaX SP2/SP2HF (sp2 driver)

 - one new frontend driver for Toshiba ISDB-T/ISDB-S demod (tc90522)

 - one new PCI driver for ISDB-T/ISDB-S (pt3 driver)

 - saa7134 driver got support for go7007-based devices

 - added a new PCI driver for Techwell 68xx chipsets (tw68)

 - a new platform driver was added (coda)

 - new tuner drivers: mxl301rf and qm1d1c0042

 - a new DVB USB driver was added for DVBSky S860 & similar devices

 - added a new SDR driver (hackrf)

 - usbtv got audio support

 - several platform drivers are now compiled with COMPILE_TEST

 - a series of compiler fixup patches, making sparse/spatch happier with
   the media stuff and removing several warnings, especially on those
   platform drivers that didn't use to compile on x86

 - Support for several new modern devices got added

 - lots of other fixes, improvements and cleanups

* tag 'media/v3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (544 commits)
  [media] ir-hix5hd2: fix build on c6x arch
  [media] pt3: fix DTV FE I2C driver load error paths
  Revert "[media] media: em28xx - remove reset_resume interface"
  [media] exynos4-is: fix some warnings when compiling on arm64
  [media] usb drivers: use %zu instead of %zd
  [media] pci drivers: use %zu instead of %zd
  [media] dvb-frontends: use %zu instead of %zd
  [media] s5p-mfc: Fix several printk warnings
  [media] s5p_mfc_opr: Fix warnings
  [media] ti-vpe: Fix typecast
  [media] s3c-camif: fix dma_addr_t printks
  [media] s5p_mfc_opr_v6: get rid of warnings when compiled with 64 bits
  [media] s5p_mfc_opr_v5: Fix lots of warnings on x86_64
  [media] em28xx: Fix identation
  [media] drxd: remove a dead code
  [media] saa7146: remove return after BUG()
  [media] cx88: remove return after BUG()
  [media] cx88: fix cards table CodingStyle
  [media] radio-sf16fmr2: declare some structs as static
  [media] radio-sf16fmi: declare pnp_attached as static
  ...

Pull dma-mapping update from Marek Szyprowski:
 "Provide the dma write coherent api (available previously on ARM
  architecture) for all other architectures, which use dma_ops-based dma
  mapping implementation.

  This lets one to use the same code in the device drivers regardless of
  the selected architecture"

* 'for-v3.18' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  dma-mapping: Provide write-combine allocations
  s390: Implement dma_{alloc,free}_attrs()

Merge tag 'hwmon-for-linus-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon updates from Guenter Roeck:
 - new driver for menf21bmc.
 - convert k10temp, smsc47b397, da9052, da9055 to new hwmon API.
 - register ntc_thermistor driver with thermal subsystem.
 - add support for F15h M60h to k10temp driver.
 - add driver for MEN14F021P00 BMC HWMON driver; this required a merge
   with tag mfd-hwmon-leds-watchdog-v3.18

* tag 'hwmon-for-linus-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (ab8500) Call kernel_power_off instead of pm_power_off
  hwmon: (menf21bmc) Introduce MEN14F021P00 BMC HWMON driver
  leds: leds-menf21bmc: Introduce MEN 14F021P00 BMC LED driver
  watchdog: menf21bmc_wdt: Introduce MEN 14F021P00 BMC Watchdog driver
  mfd: menf21bmc: Introduce MEN 14F021P00 BMC MFD Core driver
  hwmon: (ntc_thermistor) Add ntc thermistor to thermal subsystem as a sensor.
  hwmon: (smsc47b397) Convert to devm_hwmon_device_register_with_groups
  MAINTAINERS: add entry for the PWM fan driver
  hwmon: (k10temp) Convert to devm_hwmon_device_register_with_groups
  hwmon: (k10temp) Add support for F15h M60h
  hwmon: (da9052) Convert to devm_hwmon_device_register_with_groups
  hwmon: (da9055) Convert to devm_hwmon_device_register_with_groups
  hwmon: (ads1015) Use of_property_read_u32 at appropriate places

Merge tag 'restart-handler-for-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull restart handler infrastructure from Guenter Roeck:
 "This series was supposed to be pulled through various trees using it,
  and I did not plan to send a separate pull request.  As it turns out,
  the pinctrl tree did not merge with it, is now upstream, and uses it,
  meaning there are now build failures.

  Please pull this series directly to fix those build failures"

* tag 'restart-handler-for-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  arm/arm64: unexport restart handlers
  watchdog: sunxi: register restart handler with kernel restart handler
  watchdog: alim7101: register restart handler with kernel restart handler
  watchdog: moxart: register restart handler with kernel restart handler
  arm: support restart through restart handler call chain
  arm64: support restart through restart handler call chain
  power/restart: call machine_restart instead of arm_pm_restart
  kernel: add support for kernel restart handler call chain

Pull percpu updates from Tejun Heo:
 "A lot of activities on percpu front.  Notable changes are...

   - percpu allocator now can take @gfp.  If @gfp doesn't contain
     GFP_KERNEL, it tries to allocate from what's already available to
     the allocator and a work item tries to keep the reserve around
     certain level so that these atomic allocations usually succeed.

     This will replace the ad-hoc percpu memory pool used by
     blk-throttle and also be used by the planned blkcg support for
     writeback IOs.

     Please note that I noticed a bug in how @gfp is interpreted while
     preparing this pull request and applied the fix 6ae833c7
     ("percpu: fix how @gfp is interpreted by the percpu allocator")
     just now.

   - percpu_ref now uses longs for percpu and global counters instead of
     ints.  It leads to more sparse packing of the percpu counters on
     64bit machines but the overhead should be negligible and this
     allows using percpu_ref for refcnting pages and in-memory objects
     directly.

   - The switching between percpu and single counter modes of a
     percpu_ref is made independent of putting the base ref and a
     percpu_ref can now optionally be initialized in single or killed
     mode.  This allows avoiding percpu shutdown latency for cases where
     the refcounted objects may be synchronously created and destroyed
     in rapid succession with only a fraction of them reaching fully
     operational status (SCSI probing does this when combined with
     blk-mq support).  It's also planned to be used to implement forced
     single mode to detect underflow more timely for debugging.

  There's a separate branch percpu/for-3.18-consistent-ops which cleans
  up the duplicate percpu accessors.  That branch causes a number of
  conflicts with s390 and other trees.  I'll send a separate pull
  request w/ resolutions once other branches are merged"

* 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (33 commits)
  percpu: fix how @gfp is interpreted by the percpu allocator
  blk-mq, percpu_ref: start q->mq_usage_counter in atomic mode
  percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky
  percpu_ref: add PERCPU_REF_INIT_* flags
  percpu_ref: decouple switching to percpu mode and reinit
  percpu_ref: decouple switching to atomic mode and killing
  percpu_ref: add PCPU_REF_DEAD
  percpu_ref: rename things to prepare for decoupling percpu/atomic mode switch
  percpu_ref: replace pcpu_ prefix with percpu_
  percpu_ref: minor code and comment updates
  percpu_ref: relocate percpu_ref_reinit()
  Revert "blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe"
  Revert "percpu: free percpu allocation info for uniprocessor system"
  percpu-refcount: make percpu_ref based on longs instead of ints
  percpu-refcount: improve WARN messages
  percpu: fix locking regression in the failure path of pcpu_alloc()
  percpu-refcount: add @gfp to percpu_ref_init()
  proportions: add @gfp to init functions
  percpu_counter: add @gfp to percpu_counter_init()
  percpu_counter: make percpu_counters_lock irq-safe
  ...

Pull cgroup updates from Tejun Heo:
 "Nothing too interesting.  Just a handful of cleanup patches"

* 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  Revert "cgroup: remove redundant variable in cgroup_mount()"
  cgroup: remove redundant variable in cgroup_mount()
  cgroup: fix missing unlock in cgroup_release_agent()
  cgroup: remove CGRP_RELEASABLE flag
  perf/cgroup: Remove perf_put_cgroup()
  cgroup: remove redundant check in cgroup_ino()
  cpuset: simplify proc_cpuset_show()
  cgroup: simplify proc_cgroup_show()
  cgroup: use a per-cgroup work for release agent
  cgroup: remove bogus comments
  cgroup: remove redundant code in cgroup_rmdir()
  cgroup: remove some useless forward declarations
  cgroup: fix a typo in comment.

Pull libata update from Tejun Heo:
 "AHCI is getting per-port irq handling and locks for better
  scalability.  The gain is not huge but measureable with multiple high
  iops devices connected to the same host; however, the value of
  threaded IRQ handling seems negligible for AHCI and it likely will
  revert to non-threaded handling soon.

  Another noteworthy change is George Spelvin's "libata: Un-break ATA
  blacklist".  During 3.17 devel cycle, the libata blacklist glob
  matching got generalized and rewritten; unfortunately, the patch
  forgot to swap arguments to match the new match function and ended up
  breaking blacklist matching completely.  It got noticed only a couple
  days ago so it couldn't make for-3.17-fixes either.  :(

  Other than the above two, nothing too interesting - the usual cleanup
  churns and device-specific changes"

* 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata: (22 commits)
  pata_serverworks: disable 64-KB DMA transfers on Broadcom OSB4 IDE Controller
  libata: Un-break ATA blacklist
  AHCI: Do not acquire ata_host::lock from single IRQ handler
  AHCI: Optimize single IRQ interrupt processing
  AHCI: Do not read HOST_IRQ_STAT reg in multi-MSI mode
  AHCI: Make few function names more descriptive
  AHCI: Move host activation code into ahci_host_activate()
  AHCI: Move ahci_host_activate() function to libahci.c
  AHCI: Pass SCSI host template as arg to ahci_host_activate()
  ata: pata_imx: Use the SIMPLE_DEV_PM_OPS() macro
  AHCI: Cleanup checking of multiple MSIs/SLM modes
  libata-sff: Fix controllers with no ctl port
  ahci_xgene: Fix the error print invalid resource for APM X-Gene SoC AHCI SATA Host Controller driver.
  libata: change ata_<foo>_printk routines to return void
  ata: qcom: Add device tree bindings information
  ahci-platform: Bump max number of clocks to 5
  ahci: ahci_p5wdh_workaround - constify DMI table
  libahci_platform: Staticize ahci_platform_<en/dis>able_phys()
  pata_platform: Remove useless irq_flags field
  pata_of_platform: Remove "electra-ide" quirk
  ...

Merge patch-bomb from Andrew Morton:
 - part of OCFS2 (review is laggy again)
 - procfs
 - slab
 - all of MM
 - zram, zbud
 - various other random things: arch, filesystems.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (164 commits)
  nosave: consolidate __nosave_{begin,end} in <asm/sections.h>
  include/linux/screen_info.h: remove unused ORIG_* macros
  kernel/sys.c: compat sysinfo syscall: fix undefined behavior
  kernel/sys.c: whitespace fixes
  acct: eliminate compile warning
  kernel/async.c: switch to pr_foo()
  include/linux/blkdev.h: use NULL instead of zero
  include/linux/kernel.h: deduplicate code implementing clamp* macros
  include/linux/kernel.h: rewrite min3, max3 and clamp using min and max
  alpha: use Kbuild logic to include <asm-generic/sections.h>
  frv: remove deprecated IRQF_DISABLED
  frv: remove unused cpuinfo_frv and friends to fix future build error
  zbud: avoid accessing last unused freelist
  zsmalloc: simplify init_zspage free obj linking
  mm/zsmalloc.c: correct comment for fullness group computation
  zram: use notify_free to account all free notifications
  zram: report maximum used memory
  zram: zram memory size limitation
  zsmalloc: change return value unit of zs_get_total_size_bytes
  zsmalloc: move pages_allocated to zs_pool
  ...

The different architectures used their own (and different) declarations:

    extern __visible const void __nosave_begin, __nosave_end;
    extern const void __nosave_begin, __nosave_end;
    extern long __nosave_begin, __nosave_end;

Consolidate them using the first variant in <asm/sections.h>.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The ORIG_* macros definitions to access struct screen_info members and all
of their users were removed 7 years ago by commit 3ea33510
("Remove magic macros for screen_info structure members"), but (only) the
definitions reappeared a few days later in commit ee8e7cfe ("Make
asm-x86/bootparam.h includable from userspace.").

Remove them for good. Amen.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix undefined behavior and compiler warning by replacing right shift 32
with upper_32_bits macro
Signed-off-by: Scotty Bauer <sbauer@eng.utah.edu>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix minor errors and warning messages in kernel/sys.c.  These errors were
reported by checkpatch while working with some modifications in sys.c
file.  Fixing this first will help me to improve my further patches.

ERROR: trailing whitespace - 9
ERROR: do not use assignment in if condition - 4
ERROR: spaces required around that '?' (ctx:VxO) - 10
ERROR: switch and case should be at the same indent - 3

total 26 errors & 3 warnings fixed.
Signed-off-by: vishnu.ps <vishnu.ps@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If ACCT_VERSION is not defined to 3, below warning appears:
  CC      kernel/acct.o
  kernel/acct.c: In function `do_acct_process':
  kernel/acct.c:475:24: warning: unused variable `ns' [-Wunused-variable]

[akpm@linux-foundation.org: retain the local for code size improvements
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Ionut Alexa <ionut.m.alexa@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Quite useless but it shuts up some warnings.
Signed-off-by: Michele Curti <michele.curti@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Instead of open-coding clamp_t macro min_t and max_t the way clamp macro
does and instead of open-coding clamp_val simply use clamp_t.
Furthermore, normalise argument naming in the macros to be lo and hi.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Mark Rustad <mark.d.rustad@intel.com>
Cc: "Kirsher, Jeffrey T" <jeffrey.t.kirsher@intel.com>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It appears that gcc is better at optimising a double call to min and max
rather than open coded min3 and max3.  This can be observed here:

    $ cat min-max.c
    #define min(x, y) ({				\
    	typeof(x) _min1 = (x);			\
    	typeof(y) _min2 = (y);			\
    	(void) (&_min1 == &_min2);		\
    	_min1 < _min2 ? _min1 : _min2; })
    #define min3(x, y, z) ({			\
    	typeof(x) _min1 = (x);			\
    	typeof(y) _min2 = (y);			\
    	typeof(z) _min3 = (z);			\
    	(void) (&_min1 == &_min2);		\
    	(void) (&_min1 == &_min3);		\
    	_min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
    		(_min2 < _min3 ? _min2 : _min3); })

    int fmin3(int x, int y, int z) { return min3(x, y, z); }
    int fmin2(int x, int y, int z) { return min(min(x, y), z); }

    $ gcc -O2 -o min-max.s -S min-max.c; cat min-max.s
    	.file	"min-max.c"
    	.text
    	.p2align 4,,15
    	.globl	fmin3
    	.type	fmin3, @function
    fmin3:
    .LFB0:
    	.cfi_startproc
    	cmpl	%esi, %edi
    	jl	.L5
    	cmpl	%esi, %edx
    	movl	%esi, %eax
    	cmovle	%edx, %eax
    	ret
    	.p2align 4,,10
    	.p2align 3
    .L5:
    	cmpl	%edi, %edx
    	movl	%edi, %eax
    	cmovle	%edx, %eax
    	ret
    	.cfi_endproc
    .LFE0:
    	.size	fmin3, .-fmin3
    	.p2align 4,,15
    	.globl	fmin2
    	.type	fmin2, @function
    fmin2:
    .LFB1:
    	.cfi_startproc
    	cmpl	%edi, %esi
    	movl	%edx, %eax
    	cmovle	%esi, %edi
    	cmpl	%edx, %edi
    	cmovle	%edi, %eax
    	ret
    	.cfi_endproc
    .LFE1:
    	.size	fmin2, .-fmin2
    	.ident	"GCC: (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3"
    	.section	.note.GNU-stack,"",@progbits

fmin3 function, which uses open-coded min3 macro, is compiled into total
of ten instructions including a conditional branch, whereas fmin2
function, which uses two calls to min2 macro, is compiled into six
instructions with no branches.

Similarly, open-coded clamp produces the same code as clamp using min and
max macros, but the latter is much shorter:

    $ cat clamp.c
    #define clamp(val, min, max) ({			\
    	typeof(val) __val = (val);		\
    	typeof(min) __min = (min);		\
    	typeof(max) __max = (max);		\
    	(void) (&__val == &__min);		\
    	(void) (&__val == &__max);		\
    	__val = __val < __min ? __min: __val;	\
    	__val > __max ? __max: __val; })
    #define min(x, y) ({				\
    	typeof(x) _min1 = (x);			\
    	typeof(y) _min2 = (y);			\
    	(void) (&_min1 == &_min2);		\
    	_min1 < _min2 ? _min1 : _min2; })
    #define max(x, y) ({				\
    	typeof(x) _max1 = (x);			\
    	typeof(y) _max2 = (y);			\
    	(void) (&_max1 == &_max2);		\
    	_max1 > _max2 ? _max1 : _max2; })

    int fclamp(int v, int min, int max) { return clamp(v, min, max); }
    int fclampmm(int v, int min, int max) { return min(max(v, min), max); }

    $ gcc -O2 -o clamp.s -S clamp.c; cat clamp.s
    	.file	"clamp.c"
    	.text
    	.p2align 4,,15
    	.globl	fclamp
    	.type	fclamp, @function
    fclamp:
    .LFB0:
    	.cfi_startproc
    	cmpl	%edi, %esi
    	movl	%edx, %eax
    	cmovge	%esi, %edi
    	cmpl	%edx, %edi
    	cmovle	%edi, %eax
    	ret
    	.cfi_endproc
    .LFE0:
    	.size	fclamp, .-fclamp
    	.p2align 4,,15
    	.globl	fclampmm
    	.type	fclampmm, @function
    fclampmm:
    .LFB1:
    	.cfi_startproc
    	cmpl	%edi, %esi
    	cmovge	%esi, %edi
    	cmpl	%edi, %edx
    	movl	%edi, %eax
    	cmovle	%edx, %eax
    	ret
    	.cfi_endproc
    .LFE1:
    	.size	fclampmm, .-fclampmm
    	.ident	"GCC: (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3"
    	.section	.note.GNU-stack,"",@progbits

    Linux mpn-glaptop 3.13.0-29-generic #53~precise1-Ubuntu SMP Wed Jun 4 22:06:25 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
    gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
    Copyright (C) 2011 Free Software Foundation, Inc.
    This is free software; see the source for copying conditions.  There is NO
    warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

    -rwx------ 1 mpn eng 51224656 Jun 17 14:15 vmlinux.before
    -rwx------ 1 mpn eng 51224608 Jun 17 13:57 vmlinux.after

48 bytes reduction.  The do_fault_around was a few instruction shorter
and as far as I can tell saved 12 bytes on the stack, i.e.:

    $ grep -e rsp -e pop -e push do_fault_around.*
    do_fault_around.before.s:push   %rbp
    do_fault_around.before.s:mov    %rsp,%rbp
    do_fault_around.before.s:push   %r13
    do_fault_around.before.s:push   %r12
    do_fault_around.before.s:push   %rbx
    do_fault_around.before.s:sub    $0x38,%rsp
    do_fault_around.before.s:add    $0x38,%rsp
    do_fault_around.before.s:pop    %rbx
    do_fault_around.before.s:pop    %r12
    do_fault_around.before.s:pop    %r13
    do_fault_around.before.s:pop    %rbp

    do_fault_around.after.s:push   %rbp
    do_fault_around.after.s:mov    %rsp,%rbp
    do_fault_around.after.s:push   %r12
    do_fault_around.after.s:push   %rbx
    do_fault_around.after.s:sub    $0x30,%rsp
    do_fault_around.after.s:add    $0x30,%rsp
    do_fault_around.after.s:pop    %rbx
    do_fault_around.after.s:pop    %r12
    do_fault_around.after.s:pop    %rbp

or here side-by-side:

    Before                    After
    push   %rbp               push   %rbp
    mov    %rsp,%rbp          mov    %rsp,%rbp
    push   %r13
    push   %r12               push   %r12
    push   %rbx               push   %rbx
    sub    $0x38,%rsp         sub    $0x30,%rsp
    add    $0x38,%rsp         add    $0x30,%rsp
    pop    %rbx               pop    %rbx
    pop    %r12               pop    %r12
    pop    %r13
    pop    %rbp               pop    %rbp

There are also fewer branches:

    $ grep ^j do_fault_around.*
    do_fault_around.before.s:jae    ffffffff812079b7
    do_fault_around.before.s:jmp    ffffffff812079c5
    do_fault_around.before.s:jmp    ffffffff81207a14
    do_fault_around.before.s:ja     ffffffff812079f9
    do_fault_around.before.s:jb     ffffffff81207a10
    do_fault_around.before.s:jmp    ffffffff81207a63
    do_fault_around.before.s:jne    ffffffff812079df

    do_fault_around.after.s:jmp    ffffffff812079fd
    do_fault_around.after.s:ja     ffffffff812079e2
    do_fault_around.after.s:jb     ffffffff812079f9
    do_fault_around.after.s:jmp    ffffffff81207a4c
    do_fault_around.after.s:jne    ffffffff812079c8

And here's with allyesconfig on a different machine:

    $ uname -a; gcc --version; ls -l vmlinux.*
    Linux erwin 3.14.7-mn #54 SMP Sun Jun 15 11:25:08 CEST 2014 x86_64 AMD Phenom(tm) II X3 710 Processor AuthenticAMD GNU/Linux
    gcc (GCC) 4.8.3
    Copyright (C) 2013 Free Software Foundation, Inc.
    This is free software; see the source for copying conditions.  There is NO
    warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

    -rwx------ 1 mpn eng 437027411 Jun 20 16:04 vmlinux.before
    -rwx------ 1 mpn eng 437026881 Jun 20 15:30 vmlinux.after

530 bytes reduction.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: David Rientjes <rientjes@google.com>
Cc: "Rustad, Mark D" <mark.d.rustad@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Remove the IRQF_DISABLED flag from FRV architecture code.  It's a NOOP
since 2.6.35 and it will be removed one day.
Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Frv has a macro named cpu_data, interfering with variables and struct
members with the same name:

include/linux/pm_domain.h:75:24: error: expected identifier or '('
before '&' token
  struct gpd_cpu_data *cpu_data;

As struct cpuinfo_frv, boot_cpu_data, cpu_data, and current_cpu_data are
not used, removed them to fix this.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

For now, there are NCHUNKS of 64 freelists in zbud_pool, the last
unbuddied[63] freelist linked with all zbud pages which have free chunks
of 63.  Calculating according to context of num_free_chunks(), our max
chunk number of unbuddied zbud page is 62, so none of zbud pages will be
added/removed in last freelist, but still we will try to find an unbuddied
zbud page in the last unused freelist, it is unneeded.

This patch redefines NCHUNKS to 63 as free chunk number in one zbud page,
hence we can decrease size of zpool and avoid accessing the last unused
freelist whenever failing to allocate zbud from freelist in zbud_alloc.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Cc: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change zsmalloc init_zspage() logic to iterate through each object on each
of its pages, checking the offset to verify the object is on the current
page before linking it into the zspage.

The current zsmalloc init_zspage free object linking code has logic that
relies on there only being one page per zspage when PAGE_SIZE is a
multiple of class->size.  It calculates the number of objects for the
current page, and iterates through all of them plus one, to account for
the assumed partial object at the end of the page.  While this currently
works, the logic can be simplified to just link the object at each
successive offset until the offset is larger than PAGE_SIZE, which does
not rely on PAGE_SIZE being a multiple of class->size.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The letter 'f' in "n <= N/f" stands for fullness_threshold_frac, not
1/fullness_threshold_frac.
Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

`notify_free' device attribute accounts the number of slot free
notifications and internally represents the number of zram_free_page()
calls.  Slot free notifications are sent only when device is used as a
swap device, hence `notify_free' is used only for swap devices.  Since
f4659d8e (zram: support REQ_DISCARD) ZRAM handles yet another one
free notification (also via zram_free_page() call) -- REQ_DISCARD
requests, which are sent by a filesystem, whenever some data blocks are
discarded.  However, there is no way to know the number of notifications
in the latter case.

Use `notify_free' to account the number of pages freed by
zram_bio_discard() and zram_slot_free_notify().  Depending on usage
scenario `notify_free' represents:

 a) the number of pages freed because of slot free notifications, which is
   equal to the number of swap_slot_free_notify() calls, so there is no
   behaviour change

 b) the number of pages freed because of REQ_DISCARD notifications
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Normally, zram user could get maximum memory usage zram consumed via
polling mem_used_total with sysfs in userspace.

But it has a critical problem because user can miss peak memory usage
during update inverval of polling.  For avoiding that, user should poll it
with shorter interval(ie, 0.0000000001s) with mlocking to avoid page fault
delay when memory pressure is heavy.  It would be troublesome.

This patch adds new knob "mem_used_max" so user could see the maximum
memory usage easily via reading the knob and reset it via "echo 0 >
/sys/block/zram0/mem_used_max".
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Reviewed-by: David Horner <ds2horner@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Since zram has no control feature to limit memory usage, it makes hard to
manage system memrory.

This patch adds new knob "mem_limit" via sysfs to set up the a limit so
that zram could fail allocation once it reaches the limit.

In addition, user could change the limit in runtime so that he could
manage the memory more dynamically.

Initial state is no limit so it doesn't break old behavior.

[akpm@linux-foundation.org: fix typo, per Sergey]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: David Horner <ds2horner@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zs_get_total_size_bytes returns a amount of memory zsmalloc consumed with
*byte unit* but zsmalloc operates *page unit* rather than byte unit so
let's change the API so benefit we could get is that reduce unnecessary
overhead (ie, change page unit with byte unit) in zsmalloc.

Since return type is pages, "zs_get_total_pages" is better than
"zs_get_total_size_bytes".
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: David Horner <ds2horner@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently, zram has no feature to limit memory so theoretically zram can
deplete system memory.  Users have asked for a limit several times as even
without exhaustion zram makes it hard to control memory usage of the
platform.  This patchset adds the feature.

Patch 1 makes zs_get_total_size_bytes faster because it would be used
frequently in later patches for the new feature.

Patch 2 changes zs_get_total_size_bytes's return unit from bytes to page
so that zsmalloc doesn't need unnecessary operation(ie, << PAGE_SHIFT).

Patch 3 adds new feature.  I added the feature into zram layer, not
zsmalloc because limiation is zram's requirement, not zsmalloc so any
other user using zsmalloc(ie, zpool) shouldn't affected by unnecessary
branch of zsmalloc.  In future, if every users of zsmalloc want the
feature, then, we could move the feature from client side to zsmalloc
easily but vice versa would be painful.

Patch 4 adds news facility to report maximum memory usage of zram so that
this avoids user polling frequently via /sys/block/zram0/ mem_used_total
and ensures transient max are not missed.

This patch (of 4):

pages_allocated has counted in size_class structure and when user of
zsmalloc want to see total_size_bytes, it should gather all of count from
each size_class to report the sum.

It's not bad if user don't see the value often but if user start to see
the value frequently, it would be not a good deal for performance pov.

This patch moves the count from size_class to zs_pool so it could reduce
memory footprint (from [255 * 8byte] to [sizeof(atomic_long_t)]).
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Reviewed-by: David Horner <ds2horner@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Performing vma lookups without taking the mm->mmap_sem is asking for
trouble.  While doing the search, the vma in question can be modified or
even removed before returning to the caller.  Take the lock (shared) in
order to avoid races while iterating through the vmacache and/or rbtree.
In addition, this guarantees that the address space will remain intact
during the CPU flushing.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

vmstat workers are used for folding counter differentials into the zone,
per node and global counters at certain time intervals.  They currently
run at defined intervals on all processors which will cause some holdoff
for processors that need minimal intrusion by the OS.

The current vmstat_update mechanism depends on a deferrable timer firing
every other second by default which registers a work queue item that runs
on the local CPU, with the result that we have 1 interrupt and one
additional schedulable task on each CPU every 2 seconds If a workload
indeed causes VM activity or multiple tasks are running on a CPU, then
there are probably bigger issues to deal with.

However, some workloads dedicate a CPU for a single CPU bound task.  This
is done in high performance computing, in high frequency financial
applications, in networking (Intel DPDK, EZchip NPS) and with the advent
of systems with more and more CPUs over time, this may become more and
more common to do since when one has enough CPUs one cares less about
efficiently sharing a CPU with other tasks and more about efficiently
monopolizing a CPU per task.

The difference of having this timer firing and workqueue kernel thread
scheduled per second can be enormous.  An artificial test measuring the
worst case time to do a simple "i++" in an endless loop on a bare metal
system and under Linux on an isolated CPU with dynticks and with and
without this patch, have Linux match the bare metal performance (~700
cycles) with this patch and loose by couple of orders of magnitude (~200k
cycles) without it[*].  The loss occurs for something that just calculates
statistics.  For networking applications, for example, this could be the
difference between dropping packets or sustaining line rate.

Statistics are important and useful, but it would be great if there would
be a way to not cause statistics gathering produce a huge performance
difference.  This patche does just that.

This patch creates a vmstat shepherd worker that monitors the per cpu
differentials on all processors.  If there are differentials on a
processor then a vmstat worker local to the processors with the
differentials is created.  That worker will then start folding the diffs
in regular intervals.  Should the worker find that there is no work to be
done then it will make the shepherd worker monitor the differentials
again.

With this patch it is possible then to have periods longer than
2 seconds without any OS event on a "cpu" (hardware thread).

The patch shows a very minor increased in system performance.

hackbench -s 512 -l 2000 -g 15 -f 25 -P

Results before the patch:

Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.992
Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.971
Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 5.063

Hackbench after the patch:

Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.973
Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.990
Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks)
Each sender will pass 2000 messages of 512 bytes
Time: 4.993

[fengguang.wu@intel.com: cpu_stat_off can be static]
Signed-off-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Max Krasnyansky <maxk@qti.qualcomm.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It isn't obvious that CMA can be disabled on the kernel's command line, so
document it.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Chuck Ebbert <cebbert.lkml@gmail.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Increase the buffer-head per-CPU LRU size to allow efficient filesystem
operations that access many blocks for each transaction.  For example,
creating a file in a large ext4 directory with quota enabled will access
multiple buffer heads and will overflow the LRU at the default 8-block LRU
size:

* parent directory inode table block (ctime, nlinks for subdirs)
* new inode bitmap
* inode table block
* 2 quota blocks
* directory leaf block (not reused, but pollutes one cache entry)
* 2 levels htree blocks (only one is reused, other pollutes cache)
* 2 levels indirect/index blocks (only one is reused)

The buffer-head per-CPU LRU size is raised to 16, as it shows in metadata
performance benchmarks up to 10% gain for create, 4% for lookup and 7% for
destroy.
Signed-off-by: Liang Zhen <liang.zhen@intel.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Sebastien Buisson <sebastien.buisson@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PROT_NUMA VMAs are skipped to avoid problems distinguishing between
present, prot_none and special entries.  MPOL_MF_LAZY is not visible from
userspace since commit a720094d ("mm: mempolicy: Hide MPOL_NOOP and
MPOL_MF_LAZY from userspace for now") but it should still skip VMAs the
same way task_numa_work does.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>