profile/common/platform/kernel/linux-artik7.git
9 years agozram: add `compact` sysfs entry to documentation
Sergey Senozhatsky [Thu, 25 Jun 2015 22:00:00 +0000 (15:00 -0700)]
zram: add `compact` sysfs entry to documentation

We currently don't support zram on-demand device creation.  The only way
to have N zram devices is to specify num_devices module parameter (default
value 1).  That means that if, for some reason, at some point, user wants
to have N + 1 devies he/she must umount all the existing devices, unload
the module, load the module passing num_devices equals to N + 1.

This patchset introduces zram-control sysfs class, which has two sysfs
attrs:

 - hot_add     -- add a new zram device
 - hot_remove  -- remove a specific (device_id) zram device

    Usage example:
        # add a new specific zram device
        cat /sys/class/zram-control/hot_add
        1

        # remove a specific zram device
        echo 4 > /sys/class/zram-control/hot_remove

This patch (of 10):

Briefly describe missing `compact` sysfs entry.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@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>
9 years agozsmalloc: remove obsolete ZSMALLOC_DEBUG
Marcin Jabrzyk [Thu, 25 Jun 2015 21:59:58 +0000 (14:59 -0700)]
zsmalloc: remove obsolete ZSMALLOC_DEBUG

The DEBUG define in zsmalloc is useless, there is no usage of it at all.

Signed-off-by: Marcin Jabrzyk <m.jabrzyk@samsung.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agozram: remove obsolete ZRAM_DEBUG option
Marcin Jabrzyk [Thu, 25 Jun 2015 21:59:55 +0000 (14:59 -0700)]
zram: remove obsolete ZRAM_DEBUG option

This config option doesn't provide any usage for zram.

Signed-off-by: Marcin Jabrzyk <m.jabrzyk@samsung.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agos390/mm: change HPAGE_SHIFT type to int
Dominik Dingel [Thu, 25 Jun 2015 21:59:52 +0000 (14:59 -0700)]
s390/mm: change HPAGE_SHIFT type to int

With making HPAGE_SHIFT an unsigned integer we also accidentally changed
pageblock_order.  In order to avoid compiler warnings we make
HPAGE_SHFIT an int again.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agos390/mm: forward check for huge pmds to pmd_large()
Dominik Dingel [Thu, 25 Jun 2015 21:59:49 +0000 (14:59 -0700)]
s390/mm: forward check for huge pmds to pmd_large()

We already do the check in pmd_large, so we can just forward the call.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agos390/hugetlb: remove dead code for sw emulated huge pages
Dominik Dingel [Thu, 25 Jun 2015 21:59:47 +0000 (14:59 -0700)]
s390/hugetlb: remove dead code for sw emulated huge pages

We now support only hugepages on hardware with EDAT1 support.  So we
remove the prepare/release_hugepage hooks and simplify set_huge_pte_at
and huge_ptep_get.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/hugetlb: remove arch_prepare/release_hugepage from arch headers
Dominik Dingel [Thu, 25 Jun 2015 21:59:44 +0000 (14:59 -0700)]
mm/hugetlb: remove arch_prepare/release_hugepage from arch headers

Nobody used these hooks so they were removed from common code, and can now
be removed from the architectures.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/hugetlb: remove unused arch hook prepare/release_hugepage
Dominik Dingel [Thu, 25 Jun 2015 21:59:42 +0000 (14:59 -0700)]
mm/hugetlb: remove unused arch hook prepare/release_hugepage

With s390 dropping support for emulated hugepages, the last user of
arch_prepare_hugepage and arch_release_hugepage is gone.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agos390/mm: make hugepages_supported a boot time decision
Dominik Dingel [Thu, 25 Jun 2015 21:59:39 +0000 (14:59 -0700)]
s390/mm: make hugepages_supported a boot time decision

There is a potential bug with KVM and hugetlbfs if the hardware does not
support hugepages (EDAT1).  We fix this by making EDAT1 a hard requirement
for hugepages and therefore removing and simplifying code.

As s390, with the sw-emulated hugepages, was the only user of
arch_prepare/release_hugepage I also removed theses calls from common and
other architecture code.

This patch (of 5):

By dropping support for hugepages on machines which do not have the
hardware feature EDAT1, we fix a potential s390 KVM bug.

The bug would happen if a guest is backed by hugetlbfs (not supported
currently), but does not get pagetables with PGSTE.  This would lead to
random memory overwrites.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoMerge branch 'akpm' (patches from Andrew)
Linus Torvalds [Thu, 25 Jun 2015 03:47:21 +0000 (20:47 -0700)]
Merge branch 'akpm' (patches from Andrew)

Merge first patchbomb from Andrew Morton:

 - a few misc things

 - ocfs2 udpates

 - kernel/watchdog.c feature work (took ages to get right)

 - most of MM.  A few tricky bits are held up and probably won't make 4.2.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (91 commits)
  mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
  mm, thp: respect MPOL_PREFERRED policy with non-local node
  tmpfs: truncate prealloc blocks past i_size
  mm/memory hotplug: print the last vmemmap region at the end of hot add memory
  mm/mmap.c: optimization of do_mmap_pgoff function
  mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
  mm: kmemleak: avoid deadlock on the kmemleak object insertion error path
  mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
  mm: kmemleak: fix delete_object_*() race when called on the same memory block
  mm: kmemleak: allow safe memory scanning during kmemleak disabling
  memcg: convert mem_cgroup->under_oom from atomic_t to int
  memcg: remove unused mem_cgroup->oom_wakeups
  frontswap: allow multiple backends
  x86, mirror: x86 enabling - find mirrored memory ranges
  mm/memblock: allocate boot time data structures from mirrored memory
  mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute
  mm: do not ignore mapping_gfp_mask in page cache allocation paths
  mm/cma.c: fix typos in comments
  mm/oom_kill.c: print points as unsigned int
  mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages
  ...

9 years agoMerge tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl...
Linus Torvalds [Thu, 25 Jun 2015 03:42:21 +0000 (20:42 -0700)]
Merge tag 'please-pull-pstore' of git://git./linux/kernel/git/aegl/linux

Pull pstore updates from Tony Luck:
 "Miscellaneous pstore improvements"

* tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  ramoops: make it possible to change mem_type param.
  pstore/ram: verify ramoops header before saving record
  fs/pstore: Optimization function ramoops_init_przs
  fs/pstore: update the backend parameter in pstore module
  pstore: do not use message compression without lock

9 years agoMerge tag 'for-f2fs-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk...
Linus Torvalds [Thu, 25 Jun 2015 03:38:29 +0000 (20:38 -0700)]
Merge tag 'for-f2fs-4.2' of git://git./linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "New features:
   - per-file encryption (e.g., ext4)
   - FALLOC_FL_ZERO_RANGE
   - FALLOC_FL_COLLAPSE_RANGE
   - RENAME_WHITEOUT

  Major enhancement/fixes:
   - recovery broken superblocks
   - enhance f2fs_trim_fs with a discard_map
   - fix a race condition on dentry block allocation
   - fix a deadlock during summary operation
   - fix a missing fiemap result

  .. and many minor bug fixes and clean-ups were done"

* tag 'for-f2fs-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (83 commits)
  f2fs: do not trim preallocated blocks when truncating after i_size
  f2fs crypto: add alloc_bounce_page
  f2fs crypto: fix to handle errors likewise ext4
  f2fs: drop the volatile_write flag only
  f2fs: skip committing valid superblock
  f2fs: setting discard option in parse_options()
  f2fs: fix to return exact trimmed size
  f2fs: support FALLOC_FL_INSERT_RANGE
  f2fs: hide common code in f2fs_replace_block
  f2fs: disable the discard option when device doesn't support
  f2fs crypto: remove alloc_page for bounce_page
  f2fs: fix a deadlock for summary page lock vs. sentry_lock
  f2fs crypto: clean up error handling in f2fs_fname_setup_filename
  f2fs crypto: avoid f2fs_inherit_context for symlink
  f2fs crypto: do not set encryption policy for non-directory by ioctl
  f2fs crypto: allow setting encryption policy once
  f2fs crypto: check context consistent for rename2
  f2fs: avoid duplicated code by reusing f2fs_read_end_io
  f2fs crypto: use per-inode tfm structure
  f2fs: recovering broken superblock during mount
  ...

9 years agoMerge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Linus Torvalds [Thu, 25 Jun 2015 03:07:10 +0000 (20:07 -0700)]
Merge branch 'for_linus' of git://git./linux/kernel/git/jack/linux-fs

Pull UDF fixes and cleanups from Jan Kara:
 "The contains some small fixes and improvements in error handling for
  UDF.

  Bundled is also one ext3 coding style fix and a fix in quota
  documentation"

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  udf: fix udf_load_pvoldesc()
  udf: remove double err declaration in udf_file_write_iter()
  UDF: support NFSv2 export
  fs: ext3: super: fixed a space coding style issue
  quota: Update documentation
  udf: Return error from udf_find_entry()
  udf: Make udf_get_filename() return error instead of 0 length file name
  udf: bug on exotic flag in udf_get_filename()
  udf: improve error management in udf_CS0toNLS()
  udf: improve error management in udf_CS0toUTF8()
  udf: unicode: update function name in comments
  udf: remove unnecessary test in udf_build_ustr_exact()
  udf: Return -ENOMEM when allocation fails in udf_get_filename()

9 years agoMerge tag 'docs-for-linus' of git://git.lwn.net/linux-2.6
Linus Torvalds [Thu, 25 Jun 2015 03:01:36 +0000 (20:01 -0700)]
Merge tag 'docs-for-linus' of git://git.lwn.net/linux-2.6

Pull documentation updates from Jonathan Corbet:
 "The main thing here is Ingo's big subdirectory documenting feature
  support for each architecture.  Beyond that, it's the usual pile of
  fixes, tweaks, and small additions"

* tag 'docs-for-linus' of git://git.lwn.net/linux-2.6: (79 commits)
  doc:md: fix typo in md.txt.
  Documentation/mic/mpssd: don't build x86 userspace when cross compiling
  Documentation/prctl: don't build tsc tests when cross compiling
  Documentation/vDSO: don't build tests when cross compiling
  Doc:ABI/testing: Fix typo in sysfs-bus-fcoe
  Doc: Docbook: Change wikipedia's URL from http to https in scsi.tmpl
  Doc: Change wikipedia's URL from http to https
  Documentation/kernel-parameters: add missing pciserial to the earlyprintk
  Doc:pps: Fix typo in pps.txt
  kbuild : Fix documentation of INSTALL_HDR_PATH
  Documentation: filesystems: updated struct file_operations documentation in vfs.txt
  kbuild: edit explanation of clean-files variable
  Doc: ja_JP: Fix typo in HOWTO
  Move freefall program from Documentation/ to tools/
  Documentation: ARM: EXYNOS: Describe boot loaders interface
  Doc:nfc: Fix typo in nfc-hci.txt
  vfs: Minor documentation fix
  Doc: networking: txtimestamp: fix printf format warning
  Documentation, intel_pstate: Improve legacy mode internal governors description
  Documentation: extend use case for EXPORT_SYMBOL_GPL()
  ...

9 years agoMerge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Linus Torvalds [Thu, 25 Jun 2015 02:56:58 +0000 (19:56 -0700)]
Merge branch 'for-linus' of git://git./linux/kernel/git/dtor/input

Pull input subsystem updates from Dmitry Torokhov:
 "Thanks to Samuel Thibault input device (keyboard) LEDs are no longer
  hardwired within the input core but use LED subsystem and so allow use
  of different triggers; Hans de Goede did a large update for the ALPS
  touchpad driver; we have new TI drv2665 haptics driver and DA9063
  OnKey driver, and host of other drivers got various fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (55 commits)
  Input: pixcir_i2c_ts - fix receive error
  MAINTAINERS: remove non existent input mt git tree
  Input: improve usage of gpiod API
  tty/vt/keyboard: define LED triggers for VT keyboard lock states
  tty/vt/keyboard: define LED triggers for VT LED states
  Input: export LEDs as class devices in sysfs
  Input: cyttsp4 - use swap() in cyttsp4_get_touch()
  Input: goodix - do not explicitly set evbits in input device
  Input: goodix - export id and version read from device
  Input: goodix - fix variable length array warning
  Input: goodix - fix alignment issues
  Input: add OnKey driver for DA9063 MFD part
  Input: elan_i2c - add product IDs FW names
  Input: elan_i2c - add support for multi IC type and iap format
  Input: focaltech - report finger width to userspace
  tty: remove platform_sysrq_reset_seq
  Input: synaptics_i2c - use proper boolean values
  Input: psmouse - use true instead of 1 for boolean values
  Input: cyapa - fix a few typos in comments
  Input: stmpe-ts - enforce device tree only mode
  ...

9 years agoMerge tag 'edac_for_4.2_2' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp
Linus Torvalds [Thu, 25 Jun 2015 02:52:06 +0000 (19:52 -0700)]
Merge tag 'edac_for_4.2_2' of git://git./linux/kernel/git/bp/bp

Pull EDAC updates from Borislav Petkov:

 - New APM X-Gene SoC EDAC driver (Loc Ho)

 - AMD error injection module improvements (Aravind Gopalakrishnan)

 - Altera Arria 10 support (Thor Thayer)

 - misc fixes and cleanups all over the place

* tag 'edac_for_4.2_2' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp: (28 commits)
  EDAC: Update Documentation/edac.txt
  EDAC: Fix typos in Documentation/edac.txt
  EDAC, mce_amd_inj: Set MISCV on injection
  EDAC, mce_amd_inj: Move bit preparations before the injection
  EDAC, mce_amd_inj: Cleanup and simplify README
  EDAC, altera: Do not allow suspend when EDAC is enabled
  EDAC, mce_amd_inj: Make inj_type static
  arm: socfpga: dts: Add Arria10 SDRAM EDAC DTS support
  EDAC, altera: Add Arria10 EDAC support
  EDAC, altera: Refactor for Altera CycloneV SoC
  EDAC, altera: Generalize driver to use DT Memory size
  EDAC, mce_amd_inj: Add README file
  EDAC, mce_amd_inj: Add individual permissions field to dfs_node
  EDAC, mce_amd_inj: Modify flags attribute to use string arguments
  EDAC, mce_amd_inj: Read out number of MCE banks from the hardware
  EDAC, mce_amd_inj: Use MCE_INJECT_GET macro for bank node too
  EDAC, xgene: Fix cpuid abuse
  EDAC, mpc85xx: Extend error address to 64 bit
  EDAC, mpc8xxx: Adapt for FSL SoC
  EDAC, edac_stub: Drop arch-specific include
  ...

9 years agoMerge tag 'pinctrl-v4.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw...
Linus Torvalds [Thu, 25 Jun 2015 02:21:02 +0000 (19:21 -0700)]
Merge tag 'pinctrl-v4.2-1' of git://git./linux/kernel/git/linusw/linux-pinctrl

Pull pin control updates from Linus Walleij:
 "Here is the bulk of pin control changes for the v4.2 series: Quite a
  lot of new SoC subdrivers and two new main drivers this time, apart
  from that business as usual.

  Details:

  Core functionality:
   - Enable exclusive pin ownership: it is possible to flag a pin
     controller so that GPIO and other functions cannot use a single pin
     simultaneously.

  New drivers:
   - NXP LPC18xx System Control Unit pin controller
   - Imagination Pistachio SoC pin controller

  New subdrivers:
   - Freescale i.MX7d SoC
   - Intel Sunrisepoint-H PCH
   - Renesas PFC R8A7793
   - Renesas PFC R8A7794
   - Mediatek MT6397, MT8127
   - SiRF Atlas 7
   - Allwinner A33
   - Qualcomm MSM8660
   - Marvell Armada 395
   - Rockchip RK3368

  Cleanups:
   - A big cleanup of the Marvell MVEBU driver rectifying it to
     correspond to reality
   - Drop platform device probing from the SH PFC driver, we are now a
     DT only shop for SuperH
   - Drop obsolte multi-platform check for SH PFC
   - Various janitorial: constification, grammar etc

  Improvements:
   - The AT91 GPIO portions now supports the set_multiple() feature
   - Split out SPI pins on the Xilinx Zynq
   - Support DTs without specific function nodes in the i.MX driver"

* tag 'pinctrl-v4.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (99 commits)
  pinctrl: rockchip: add support for the rk3368
  pinctrl: rockchip: generalize perpin driver-strength setting
  pinctrl: sh-pfc: r8a7794: add SDHI pin groups
  pinctrl: sh-pfc: r8a7794: add MMCIF pin groups
  pinctrl: sh-pfc: add R8A7794 PFC support
  pinctrl: make pinctrl_register() return proper error code
  pinctrl: mvebu: armada-39x: add support for Armada 395 variant
  pinctrl: mvebu: armada-39x: add missing SATA functions
  pinctrl: mvebu: armada-39x: add missing PCIe functions
  pinctrl: mvebu: armada-38x: add ptp functions
  pinctrl: mvebu: armada-38x: add ua1 functions
  pinctrl: mvebu: armada-38x: add nand functions
  pinctrl: mvebu: armada-38x: add sata functions
  pinctrl: mvebu: armada-xp: add dram functions
  pinctrl: mvebu: armada-xp: add nand rb function
  pinctrl: mvebu: armada-xp: add spi1 function
  pinctrl: mvebu: armada-39x: normalize ref clock naming
  pinctrl: mvebu: armada-xp: rename spi to spi0
  pinctrl: mvebu: armada-370: align spi1 clock pin naming
  pinctrl: mvebu: armada-370: align VDD cpu-pd pin naming with datasheet
  ...

9 years agoMerge tag 'backlight-for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Thu, 25 Jun 2015 01:57:00 +0000 (18:57 -0700)]
Merge tag 'backlight-for-linus-4.2' of git://git./linux/kernel/git/lee/backlight

Pull backlight updates from Lee Jones:
 "Changes to existing drivers:

   - supply MODULE_DEVICE_TABLE() to ensure probing
   - constify struct; da9052_bl
   - enable compile test; lcd_l4f00242t03, lcd_lms283fg05, backlight_gpio
   - suspend/resume bugfix; lp855x_bl
   - devm_gpiod_get_optional() API fixup; pwm_bl
   - error handling fixup; backlight"

* tag 'backlight-for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: Change the return type of backlight_update_status() to int
  backlight: pwm_bl: Simplify usage of devm_gpiod_get_optional
  backlight: lp855x: Don't clear level on suspend/blank
  backlight: Allow compile test of GPIO consumers if !GPIOLIB
  video: backlight: da9052: Constify platform_device_id
  gpio-backlight: Discover driver during boot time

9 years agomm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
Larry Finger [Wed, 24 Jun 2015 23:58:51 +0000 (16:58 -0700)]
mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()

Beginning at commit d52d3997f843 ("ipv6: Create percpu rt6_info"), the
following INFO splat is logged:

  ===============================
  [ INFO: suspicious RCU usage. ]
  4.1.0-rc7-next-20150612 #1 Not tainted
  -------------------------------
  kernel/sched/core.c:7318 Illegal context switch in RCU-bh read-side critical section!
  other info that might help us debug this:
  rcu_scheduler_active = 1, debug_locks = 0
   3 locks held by systemd/1:
   #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff815f0c8f>] rtnetlink_rcv+0x1f/0x40
   #1:  (rcu_read_lock_bh){......}, at: [<ffffffff816a34e2>] ipv6_add_addr+0x62/0x540
   #2:  (addrconf_hash_lock){+...+.}, at: [<ffffffff816a3604>] ipv6_add_addr+0x184/0x540
  stack backtrace:
  CPU: 0 PID: 1 Comm: systemd Not tainted 4.1.0-rc7-next-20150612 #1
  Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.20   04/17/2014
  Call Trace:
    dump_stack+0x4c/0x6e
    lockdep_rcu_suspicious+0xe7/0x120
    ___might_sleep+0x1d5/0x1f0
    __might_sleep+0x4d/0x90
    kmem_cache_alloc+0x47/0x250
    create_object+0x39/0x2e0
    kmemleak_alloc_percpu+0x61/0xe0
    pcpu_alloc+0x370/0x630

Additional backtrace lines are truncated.  In addition, the above splat
is followed by several "BUG: sleeping function called from invalid
context at mm/slub.c:1268" outputs.  As suggested by Martin KaFai Lau,
these are the clue to the fix.  Routine kmemleak_alloc_percpu() always
uses GFP_KERNEL for its allocations, whereas it should follow the gfp
from its callers.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@vger.kernel.org> [3.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm, thp: respect MPOL_PREFERRED policy with non-local node
Vlastimil Babka [Wed, 24 Jun 2015 23:58:48 +0000 (16:58 -0700)]
mm, thp: respect MPOL_PREFERRED policy with non-local node

Since commit 077fcf116c8c ("mm/thp: allocate transparent hugepages on
local node"), we handle THP allocations on page fault in a special way -
for non-interleave memory policies, the allocation is only attempted on
the node local to the current CPU, if the policy's nodemask allows the
node.

This is motivated by the assumption that THP benefits cannot offset the
cost of remote accesses, so it's better to fallback to base pages on the
local node (which might still be available, while huge pages are not due
to fragmentation) than to allocate huge pages on a remote node.

The nodemask check prevents us from violating e.g.  MPOL_BIND policies
where the local node is not among the allowed nodes.  However, the
current implementation can still give surprising results for the
MPOL_PREFERRED policy when the preferred node is different than the
current CPU's local node.

In such case we should honor the preferred node and not use the local
node, which is what this patch does.  If hugepage allocation on the
preferred node fails, we fall back to base pages and don't try other
nodes, with the same motivation as is done for the local node hugepage
allocations.  The patch also moves the MPOL_INTERLEAVE check around to
simplify the hugepage specific test.

The difference can be demonstrated using in-tree transhuge-stress test
on the following 2-node machine where half memory on one node was
occupied to show the difference.

> numactl --hardware
available: 2 nodes (0-1)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 24 25 26 27 28 29 30 31 32 33 34 35
node 0 size: 7878 MB
node 0 free: 3623 MB
node 1 cpus: 12 13 14 15 16 17 18 19 20 21 22 23 36 37 38 39 40 41 42 43 44 45 46 47
node 1 size: 8045 MB
node 1 free: 7818 MB
node distances:
node   0   1
  0:  10  21
  1:  21  10

Before the patch:
> numactl -p0 -C0 ./transhuge-stress
transhuge-stress: 2.197 s/loop, 0.276 ms/page,   7249.168 MiB/s 7962 succeed,    0 failed, 1786 different pages

> numactl -p0 -C12 ./transhuge-stress
transhuge-stress: 2.962 s/loop, 0.372 ms/page,   5376.172 MiB/s 7962 succeed,    0 failed, 3873 different pages

Number of successful THP allocations corresponds to free memory on node 0 in
the first case and node 1 in the second case, i.e. -p parameter is ignored and
cpu binding "wins".

After the patch:
> numactl -p0 -C0 ./transhuge-stress
transhuge-stress: 2.183 s/loop, 0.274 ms/page,   7295.516 MiB/s 7962 succeed,    0 failed, 1760 different pages

> numactl -p0 -C12 ./transhuge-stress
transhuge-stress: 2.878 s/loop, 0.361 ms/page,   5533.638 MiB/s 7962 succeed,    0 failed, 1750 different pages

> numactl -p1 -C0 ./transhuge-stress
transhuge-stress: 4.628 s/loop, 0.581 ms/page,   3440.893 MiB/s 7962 succeed,    0 failed, 3918 different pages

The -p parameter is respected regardless of cpu binding.

> numactl -C0 ./transhuge-stress
transhuge-stress: 2.202 s/loop, 0.277 ms/page,   7230.003 MiB/s 7962 succeed,    0 failed, 1750 different pages

> numactl -C12 ./transhuge-stress
transhuge-stress: 3.020 s/loop, 0.379 ms/page,   5273.324 MiB/s 7962 succeed,    0 failed, 3916 different pages

Without -p parameter, hugepage restriction to CPU-local node works as before.

Fixes: 077fcf116c8c ("mm/thp: allocate transparent hugepages on local node")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org> [4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agotmpfs: truncate prealloc blocks past i_size
Josef Bacik [Wed, 24 Jun 2015 23:58:45 +0000 (16:58 -0700)]
tmpfs: truncate prealloc blocks past i_size

One of the rocksdb people noticed that when you do something like this

    fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, 10M)
    pwrite(fd, buf, 5M, 0)
    ftruncate(5M)

on tmpfs, the file would still take up 10M: which led to super fun
issues because we were getting ENOSPC before we thought we should be
getting ENOSPC.  This patch fixes the problem, and mirrors what all the
other fs'es do (and was agreed to be the correct behaviour at LSF).

I tested it locally to make sure it worked properly with the following

    xfs_io -f -c "falloc -k 0 10M" -c "pwrite 0 5M" -c "truncate 5M" file

Without the patch we have "Blocks: 20480", with the patch we have the
correct value of "Blocks: 10240".

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/memory hotplug: print the last vmemmap region at the end of hot add memory
Zhu Guihua [Wed, 24 Jun 2015 23:58:42 +0000 (16:58 -0700)]
mm/memory hotplug: print the last vmemmap region at the end of hot add memory

When hot add two nodes continuously, we found the vmemmap region info is
a bit messed.  The last region of node 2 is printed when node 3 hot
added, like the following:

  Initmem setup node 2 [mem 0x0000000000000000-0xffffffffffffffff]
   On node 2 totalpages: 0
   Built 2 zonelists in Node order, mobility grouping on.  Total pages: 16090539
   Policy zone: Normal
   init_memory_mapping: [mem 0x40000000000-0x407ffffffff]
    [mem 0x40000000000-0x407ffffffff] page 1G
    [ffffea1000000000-ffffea10001fffff] PMD -> [ffff8a077d800000-ffff8a077d9fffff] on node 2
    [ffffea1000200000-ffffea10003fffff] PMD -> [ffff8a077de00000-ffff8a077dffffff] on node 2
  ...
    [ffffea101f600000-ffffea101f9fffff] PMD -> [ffff8a074ac00000-ffff8a074affffff] on node 2
    [ffffea101fa00000-ffffea101fdfffff] PMD -> [ffff8a074a800000-ffff8a074abfffff] on node 2
  Initmem setup node 3 [mem 0x0000000000000000-0xffffffffffffffff]
   On node 3 totalpages: 0
   Built 3 zonelists in Node order, mobility grouping on.  Total pages: 16090539
   Policy zone: Normal
   init_memory_mapping: [mem 0x60000000000-0x607ffffffff]
    [mem 0x60000000000-0x607ffffffff] page 1G
    [ffffea101fe00000-ffffea101fffffff] PMD -> [ffff8a074a400000-ffff8a074a5fffff] on node 2 <=== node 2 ???
    [ffffea1800000000-ffffea18001fffff] PMD -> [ffff8a074a600000-ffff8a074a7fffff] on node 3
    [ffffea1800200000-ffffea18005fffff] PMD -> [ffff8a074a000000-ffff8a074a3fffff] on node 3
    [ffffea1800600000-ffffea18009fffff] PMD -> [ffff8a0749c00000-ffff8a0749ffffff] on node 3
  ...

The cause is the last region was missed at the and of hot add memory,
and p_start, p_end, node_start were not reset, so when hot add memory to
a new node, it will consider they are not contiguous blocks and print
the previous one.  So we print the last vmemmap region at the end of hot
add memory to avoid the confusion.

Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/mmap.c: optimization of do_mmap_pgoff function
Piotr Kwapulinski [Wed, 24 Jun 2015 23:58:39 +0000 (16:58 -0700)]
mm/mmap.c: optimization of do_mmap_pgoff function

The simple check for zero length memory mapping may be performed
earlier.  So that in case of zero length memory mapping some unnecessary
code is not executed at all.  It does not make the code less readable
and saves some CPU cycles.

Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
Catalin Marinas [Wed, 24 Jun 2015 23:58:37 +0000 (16:58 -0700)]
mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan

The kmemleak memory scanning uses finer grained object->lock spinlocks
primarily to avoid races with the memory block freeing.  However, the
pointer lookup in the rb tree requires the kmemleak_lock to be held.
This is currently done in the find_and_get_object() function for each
pointer-like location read during scanning.  While this allows a low
latency on kmemleak_*() callbacks on other CPUs, the memory scanning is
slower.

This patch moves the kmemleak_lock outside the scan_block() loop,
acquiring/releasing it only once per scanned memory block.  The
allow_resched logic is moved outside scan_block() and a new
scan_large_block() function is implemented which splits large blocks in
MAX_SCAN_SIZE chunks with cond_resched() calls in-between.  A redundant
(object->flags & OBJECT_NO_SCAN) check is also removed from
scan_object().

With this patch, the kmemleak scanning performance is significantly
improved: at least 50% with lock debugging disabled and over an order of
magnitude with lock proving enabled (on an arm64 system).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: kmemleak: avoid deadlock on the kmemleak object insertion error path
Catalin Marinas [Wed, 24 Jun 2015 23:58:34 +0000 (16:58 -0700)]
mm: kmemleak: avoid deadlock on the kmemleak object insertion error path

While very unlikely (usually kmemleak or sl*b bug), the create_object()
function in mm/kmemleak.c may fail to insert a newly allocated object into
the rb tree.  When this happens, kmemleak disables itself and prints
additional information about the object already found in the rb tree.
Such printing is done with the parent->lock acquired, however the
kmemleak_lock is already held.  This is a potential race with the scanning
thread which acquires object->lock and kmemleak_lock in a

This patch removes the locking around the 'parent' object information
printing.  Such object cannot be freed or removed from object_tree_root
and object_list since kmemleak_lock is already held.  There is a very
small risk that some of the object data is being modified on another CPU
but the only downside is inconsistent information printing.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
Catalin Marinas [Wed, 24 Jun 2015 23:58:31 +0000 (16:58 -0700)]
mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()

The kmemleak_do_cleanup() work thread already waits for the kmemleak_scan
thread to finish via kthread_stop().  Waiting in kthread_stop() while
scan_mutex is held may lead to deadlock if kmemleak_scan_thread() also
waits to acquire for scan_mutex.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: kmemleak: fix delete_object_*() race when called on the same memory block
Catalin Marinas [Wed, 24 Jun 2015 23:58:29 +0000 (16:58 -0700)]
mm: kmemleak: fix delete_object_*() race when called on the same memory block

Calling delete_object_*() on the same pointer is not a standard use case
(unless there is a bug in the code calling kmemleak_free()).  However,
during kmemleak disabling (error or user triggered via /sys), there is a
potential race between kmemleak_free() calls on a CPU and
__kmemleak_do_cleanup() on a different CPU.

The current delete_object_*() implementation first performs a look-up
holding kmemleak_lock, increments the object->use_count and then
re-acquires kmemleak_lock to remove the object from object_tree_root and
object_list.

This patch simplifies the delete_object_*() mechanism to both look up
and remove an object from the object_tree_root and object_list
atomically (guarded by kmemleak_lock).  This allows safe concurrent
calls to delete_object_*() on the same pointer without additional
locking for synchronising the kmemleak_free_enabled flag.

A side effect is a slight improvement in the delete_object_*() performance
by avoiding acquiring kmemleak_lock twice and incrementing/decrementing
object->use_count.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: kmemleak: allow safe memory scanning during kmemleak disabling
Catalin Marinas [Wed, 24 Jun 2015 23:58:26 +0000 (16:58 -0700)]
mm: kmemleak: allow safe memory scanning during kmemleak disabling

The kmemleak scanning thread can run for minutes.  Callbacks like
kmemleak_free() are allowed during this time, the race being taken care
of by the object->lock spinlock.  Such lock also prevents a memory block
from being freed or unmapped while it is being scanned by blocking the
kmemleak_free() -> ...  -> __delete_object() function until the lock is
released in scan_object().

When a kmemleak error occurs (e.g.  it fails to allocate its metadata),
kmemleak_enabled is set and __delete_object() is no longer called on
freed objects.  If kmemleak_scan is running at the same time,
kmemleak_free() no longer waits for the object scanning to complete,
allowing the corresponding memory block to be freed or unmapped (in the
case of vfree()).  This leads to kmemleak_scan potentially triggering a
page fault.

This patch separates the kmemleak_free() enabling/disabling from the
overall kmemleak_enabled nob so that we can defer the disabling of the
object freeing tracking until the scanning thread completed.  The
kmemleak_free_part() is deliberately ignored by this patch since this is
only called during boot before the scanning thread started.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org>
Tested-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomemcg: convert mem_cgroup->under_oom from atomic_t to int
Tejun Heo [Wed, 24 Jun 2015 23:58:23 +0000 (16:58 -0700)]
memcg: convert mem_cgroup->under_oom from atomic_t to int

memcg->under_oom tracks whether the memcg is under OOM conditions and is
an atomic_t counter managed with mem_cgroup_[un]mark_under_oom().  While
atomic_t appears to be simple synchronization-wise, when used as a
synchronization construct like here, it's trickier and more error-prone
due to weak memory ordering rules, especially around atomic_read(), and
false sense of security.

For example, both non-trivial read sites of memcg->under_oom are a bit
problematic although not being actually broken.

* mem_cgroup_oom_register_event()

  It isn't explicit what guarantees the memory ordering between event
  addition and memcg->under_oom check.  This isn't broken only because
  memcg_oom_lock is used for both event list and memcg->oom_lock.

* memcg_oom_recover()

  The lockless test doesn't have any explanation why this would be
  safe.

mem_cgroup_[un]mark_under_oom() are very cold paths and there's no point
in avoiding locking memcg_oom_lock there.  This patch converts
memcg->under_oom from atomic_t to int, puts their modifications under
memcg_oom_lock and documents why the lockless test in
memcg_oom_recover() is safe.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomemcg: remove unused mem_cgroup->oom_wakeups
Tejun Heo [Wed, 24 Jun 2015 23:58:21 +0000 (16:58 -0700)]
memcg: remove unused mem_cgroup->oom_wakeups

Since commit 4942642080ea ("mm: memcg: handle non-error OOM situations
more gracefully"), nobody uses mem_cgroup->oom_wakeups.  Remove it.

While at it, also fold memcg_wakeup_oom() into memcg_oom_recover() which
is its only user.  This cleanup was suggested by Michal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agofrontswap: allow multiple backends
Dan Streetman [Wed, 24 Jun 2015 23:58:18 +0000 (16:58 -0700)]
frontswap: allow multiple backends

Change frontswap single pointer to a singly linked list of frontswap
implementations.  Update Xen tmem implementation as register no longer
returns anything.

Frontswap only keeps track of a single implementation; any
implementation that registers second (or later) will replace the
previously registered implementation, and gets a pointer to the previous
implementation that the new implementation is expected to pass all
frontswap functions to if it can't handle the function itself.  However
that method doesn't really make much sense, as passing that work on to
every implementation adds unnecessary work to implementations; instead,
frontswap should simply keep a list of all registered implementations
and try each implementation for any function.  Most importantly, neither
of the two currently existing frontswap implementations in the kernel
actually do anything with any previous frontswap implementation that
they replace when registering.

This allows frontswap to successfully manage multiple implementations by
keeping a list of them all.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agox86, mirror: x86 enabling - find mirrored memory ranges
Tony Luck [Wed, 24 Jun 2015 23:58:15 +0000 (16:58 -0700)]
x86, mirror: x86 enabling - find mirrored memory ranges

UEFI GetMemoryMap() uses a new attribute bit to mark mirrored memory
address ranges.  See UEFI 2.5 spec pages 157-158:

  http://www.uefi.org/sites/default/files/resources/UEFI%202_5.pdf

On EFI enabled systems scan the memory map and tell memblock about any
mirrored ranges.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Xiexiuqi <xiexiuqi@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/memblock: allocate boot time data structures from mirrored memory
Tony Luck [Wed, 24 Jun 2015 23:58:12 +0000 (16:58 -0700)]
mm/memblock: allocate boot time data structures from mirrored memory

Try to allocate all boot time kernel data structures from mirrored
memory.

If we run out of mirrored memory print warnings, but fall back to using
non-mirrored memory to make sure that we still boot.

By number of bytes, most of what we allocate at boot time is the page
structures.  64 bytes per 4K page on x86_64 ...  or about 1.5% of total
system memory.  For workloads where the bulk of memory is allocated to
applications this may represent a useful improvement to system
availability since 1.5% of total memory might be a third of the memory
allocated to the kernel.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Xiexiuqi <xiexiuqi@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/memblock: add extra "flags" to memblock to allow selection of memory based on...
Tony Luck [Wed, 24 Jun 2015 23:58:09 +0000 (16:58 -0700)]
mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute

Some high end Intel Xeon systems report uncorrectable memory errors as a
recoverable machine check.  Linux has included code for some time to
process these and just signal the affected processes (or even recover
completely if the error was in a read only page that can be replaced by
reading from disk).

But we have no recovery path for errors encountered during kernel code
execution.  Except for some very specific cases were are unlikely to ever
be able to recover.

Enter memory mirroring. Actually 3rd generation of memory mirroing.

Gen1: All memory is mirrored
Pro: No s/w enabling - h/w just gets good data from other side of the
     mirror
Con: Halves effective memory capacity available to OS/applications

Gen2: Partial memory mirror - just mirror memory begind some memory controllers
Pro: Keep more of the capacity
Con: Nightmare to enable. Have to choose between allocating from
     mirrored memory for safety vs. NUMA local memory for performance

Gen3: Address range partial memory mirror - some mirror on each memory
      controller
Pro: Can tune the amount of mirror and keep NUMA performance
Con: I have to write memory management code to implement

The current plan is just to use mirrored memory for kernel allocations.
This has been broken into two phases:

1) This patch series - find the mirrored memory, use it for boot time
   allocations

2) Wade into mm/page_alloc.c and define a ZONE_MIRROR to pick up the
   unused mirrored memory from mm/memblock.c and only give it out to
   select kernel allocations (this is still being scoped because
   page_alloc.c is scary).

This patch (of 3):

Add extra "flags" to memblock to allow selection of memory based on
attribute.  No functional changes

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Xiexiuqi <xiexiuqi@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: do not ignore mapping_gfp_mask in page cache allocation paths
Michal Hocko [Wed, 24 Jun 2015 23:58:06 +0000 (16:58 -0700)]
mm: do not ignore mapping_gfp_mask in page cache allocation paths

page_cache_read, do_generic_file_read, __generic_file_splice_read and
__ntfs_grab_cache_pages currently ignore mapping_gfp_mask when calling
add_to_page_cache_lru which might cause recursion into fs down in the
direct reclaim path if the mapping really relies on GFP_NOFS semantic.

This doesn't seem to be the case now because page_cache_read (page fault
path) doesn't seem to suffer from the reclaim recursion issues and
do_generic_file_read and __generic_file_splice_read also shouldn't be
called under fs locks which would deadlock in the reclaim path.  Anyway it
is better to obey mapping gfp mask and prevent from later breakage.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/cma.c: fix typos in comments
Shailendra Verma [Wed, 24 Jun 2015 23:58:03 +0000 (16:58 -0700)]
mm/cma.c: fix typos in comments

Signed-off-by: Shailendra Verma <shailendra.capricorn@gmail.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/oom_kill.c: print points as unsigned int
Wang Long [Wed, 24 Jun 2015 23:58:01 +0000 (16:58 -0700)]
mm/oom_kill.c: print points as unsigned int

In oom_kill_process(), the variable 'points' is unsigned int.  Print it as
such.

Signed-off-by: Wang Long <long.wanglong@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages
Mike Kravetz [Wed, 24 Jun 2015 23:57:58 +0000 (16:57 -0700)]
mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages

alloc_huge_page and hugetlb_reserve_pages use region_chg to calculate the
number of pages which will be added to the reserve map.  Subpool and
global reserve counts are adjusted based on the output of region_chg.
Before the pages are actually added to the reserve map, these routines
could race and add fewer pages than expected.  If this happens, the
subpool and global reserve counts are not correct.

Compare the number of pages actually added (region_add) to those expected
to added (region_chg).  If fewer pages are actually added, this indicates
a race and adjust counters accordingly.

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/hugetlb: compute/return the number of regions added by region_add()
Mike Kravetz [Wed, 24 Jun 2015 23:57:55 +0000 (16:57 -0700)]
mm/hugetlb: compute/return the number of regions added by region_add()

Modify region_add() to keep track of regions(pages) added to the reserve
map and return this value.  The return value can be compared to the return
value of region_chg() to determine if the map was modified between calls.

Make vma_commit_reservation() also pass along the return value of
region_add().  In the normal case, we want vma_commit_reservation to
return the same value as the preceding call to vma_needs_reservation.
Create a common __vma_reservation_common routine to help keep the special
case return values in sync

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/hugetlb: document the reserve map/region tracking routines
Mike Kravetz [Wed, 24 Jun 2015 23:57:52 +0000 (16:57 -0700)]
mm/hugetlb: document the reserve map/region tracking routines

While working on hugetlbfs fallocate support, I noticed the following race
in the existing code.  It is unlikely that this race is hit very often in
the current code.  However, if more functionality to add and remove pages
to hugetlbfs mappings (such as fallocate) is added the likelihood of
hitting this race will increase.

alloc_huge_page and hugetlb_reserve_pages use information from the reserve
map to determine if there are enough available huge pages to complete the
operation, as well as adjust global reserve and subpool usage counts.  The
order of operations is as follows:

- call region_chg() to determine the expected change based on reserve map
- determine if enough resources are available for this operation
- adjust global counts based on the expected change
- call region_add() to update the reserve map

The issue is that reserve map could change between the call to region_chg
and region_add.  In this case, the counters which were adjusted based on
the output of region_chg will not be correct.

In order to hit this race today, there must be an existing shared hugetlb
mmap created with the MAP_NORESERVE flag.  A page fault to allocate a huge
page via this mapping must occur at the same another task is mapping the
same region without the MAP_NORESERVE flag.

The patch set does not prevent the race from happening.  Rather, it adds
simple functionality to detect when the race has occurred.  If a race is
detected, then the incorrect counts are adjusted.

Review comments pointed out the need for documentation of the existing
region/reserve map routines.  This patch set also adds documentation in
this area.

This patch (of 3):

This is a documentation only patch and does not modify any code.
Descriptions of the routines used for reserve map/region tracking are
added.

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoDocumentation/vm/unevictable-lru.txt: clarify MAP_LOCKED behavior
Michal Hocko [Wed, 24 Jun 2015 23:57:50 +0000 (16:57 -0700)]
Documentation/vm/unevictable-lru.txt: clarify MAP_LOCKED behavior

There is a very subtle difference between mmap()+mlock() vs
mmap(MAP_LOCKED) semantic.  The former one fails if the population of the
area fails while the later one doesn't.  This basically means that
mmap(MAPLOCKED) areas might see major fault after mmap syscall returns
which is not the case for mlock.  mmap man page has already been altered
but Documentation/vm/unevictable-lru.txt deserves a clarification as well.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Reported-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: nommu: refactor debug and warning prints
Leon Romanovsky [Wed, 24 Jun 2015 23:57:47 +0000 (16:57 -0700)]
mm: nommu: refactor debug and warning prints

kenter/kleave/kdebug are wrapper macros to print functions flow and debug
information.  This set was written before pr_devel() was introduced, so it
was controlled by "#if 0" construction.  It is questionable if anyone is
using them [1] now.

This patch removes these macros, converts numerous printk(KERN_WARNING,
...) to use general pr_warn(...) and removes debug print line from
validate_mmap_request() function.

Signed-off-by: Leon Romanovsky <leon@leon.nu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: clarify that the function operates on hugepage pte
Aneesh Kumar K.V [Wed, 24 Jun 2015 23:57:44 +0000 (16:57 -0700)]
mm: clarify that the function operates on hugepage pte

We have confusing functions to clear pmd, pmd_clear_* and pmd_clear.  Add
_huge_ to pmdp_clear functions so that we are clear that they operate on
hugepage pte.

We don't bother about other functions like pmdp_set_wrprotect,
pmdp_clear_flush_young, because they operate on PTE bits and hence
indicate they are operating on hugepage ptes

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agopowerpc/mm: use generic version of pmdp_clear_flush()
Aneesh Kumar K.V [Wed, 24 Jun 2015 23:57:42 +0000 (16:57 -0700)]
powerpc/mm: use generic version of pmdp_clear_flush()

Also move the pmd_trans_huge check to generic code.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/thp: split out pmd collapse flush into separate functions
Aneesh Kumar K.V [Wed, 24 Jun 2015 23:57:39 +0000 (16:57 -0700)]
mm/thp: split out pmd collapse flush into separate functions

Architectures like ppc64 [1] need to do special things while clearing pmd
before a collapse.  For them this operation is largely different from a
normal hugepage pte clear.  Hence add a separate function to clear pmd
before collapse.  After this patch pmdp_* functions operate only on
hugepage pte, and not on regular pmd_t values pointing to page table.

[1] ppc64 needs to invalidate all the normal page pte mappings we already
have inserted in the hardware hash page table.  But before doing that we
need to make sure there are no parallel hash page table insert going on.
So we need to do a kick_all_cpus_sync() before flushing the older hash
table entries.  By moving this to a separate function we capture these
details and mention how it is different from a hugepage pte clear.

This patch is a cleanup and only does code movement for clarity.  There
should not be any change in functionality.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agotracing: add trace event for memory-failure
Xie XiuQi [Wed, 24 Jun 2015 23:57:36 +0000 (16:57 -0700)]
tracing: add trace event for memory-failure

RAS user space tools like rasdaemon which base on trace event, could
receive mce error event, but no memory recovery result event.  So, I want
to add this event to make this scenario complete.

This patch add a event at ras group for memory-failure.

The output like below:
#  tracer: nop
#
#  entries-in-buffer/entries-written: 2/2   #P:24
#
#                               _-----=> irqs-off
#                              / _----=> need-resched
#                             | / _---=> hardirq/softirq
#                             || / _--=> preempt-depth
#                             ||| /     delay
#            TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
#               | |       |   ||||       |         |
       mce-inject-13150 [001] ....   277.019359: memory_failure_event: pfn 0x19869: recovery action for free buddy page: Delayed

[xiexiuqi@huawei.com: fix build error]
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomemory-failure: change type of action_result's param 3 to enum
Xie XiuQi [Wed, 24 Jun 2015 23:57:33 +0000 (16:57 -0700)]
memory-failure: change type of action_result's param 3 to enum

Change type of action_result's param 3 to enum for type consistency,
and rename mf_outcome to mf_result for clearly.

Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jim Davis <jim.epost@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomemory-failure: export page_type and action result
Xie XiuQi [Wed, 24 Jun 2015 23:57:30 +0000 (16:57 -0700)]
memory-failure: export page_type and action result

Export 'outcome' and 'action_page_type' to mm.h, so we could use
this emnus outside.

This patch is preparation for adding trace events for memory-failure
recovery action.

Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jim Davis <jim.epost@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm, memcg: Try charging a page before setting page up to date
Mel Gorman [Wed, 24 Jun 2015 23:57:27 +0000 (16:57 -0700)]
mm, memcg: Try charging a page before setting page up to date

Historically memcg overhead was high even if memcg was unused.  This has
improved a lot but it still showed up in a profile summary as being a
problem.

/usr/src/linux-4.0-vanilla/mm/memcontrol.c                           6.6441   395842
  mem_cgroup_try_charge                                                        2.950%   175781
  __mem_cgroup_count_vm_event                                                  1.431%    85239
  mem_cgroup_page_lruvec                                                       0.456%    27156
  mem_cgroup_commit_charge                                                     0.392%    23342
  uncharge_list                                                                0.323%    19256
  mem_cgroup_update_lru_size                                                   0.278%    16538
  memcg_check_events                                                           0.216%    12858
  mem_cgroup_charge_statistics.isra.22                                         0.188%    11172
  try_charge                                                                   0.150%     8928
  commit_charge                                                                0.141%     8388
  get_mem_cgroup_from_mm                                                       0.121%     7184

That is showing that 6.64% of system CPU cycles were in memcontrol.c and
dominated by mem_cgroup_try_charge.  The annotation shows that the bulk
of the cost was checking PageSwapCache which is expected to be cache hot
but is very expensive.  The problem appears to be that __SetPageUptodate
is called just before the check which is a write barrier.  It is
required to make sure struct page and page data is written before the
PTE is updated and the data visible to userspace.  memcg charging does
not require or need the barrier but gets unfairly hit with the cost so
this patch attempts the charging before the barrier.  Aside from the
accidental cost to memcg there is the added benefit that the barrier is
avoided if the page cannot be charged.  When applied the relevant
profile summary is as follows.

/usr/src/linux-4.0-chargefirst-v2r1/mm/memcontrol.c                  3.7907   223277
  __mem_cgroup_count_vm_event                                                  1.143%    67312
  mem_cgroup_page_lruvec                                                       0.465%    27403
  mem_cgroup_commit_charge                                                     0.381%    22452
  uncharge_list                                                                0.332%    19543
  mem_cgroup_update_lru_size                                                   0.284%    16704
  get_mem_cgroup_from_mm                                                       0.271%    15952
  mem_cgroup_try_charge                                                        0.237%    13982
  memcg_check_events                                                           0.222%    13058
  mem_cgroup_charge_statistics.isra.22                                         0.185%    10920
  commit_charge                                                                0.140%     8235
  try_charge                                                                   0.131%     7716

That brings the overhead down to 3.79% and leaves the memcg fault
accounting to the root cgroup but it's an improvement.  The difference
in headline performance of the page fault microbench is marginal as
memcg is such a small component of it.

pft faults
                                       4.0.0                  4.0.0
                                     vanilla            chargefirst
Hmean    faults/cpu-1 1443258.1051 (  0.00%) 1509075.7561 (  4.56%)
Hmean    faults/cpu-3 1340385.9270 (  0.00%) 1339160.7113 ( -0.09%)
Hmean    faults/cpu-5  875599.0222 (  0.00%)  874174.1255 ( -0.16%)
Hmean    faults/cpu-7  601146.6726 (  0.00%)  601370.9977 (  0.04%)
Hmean    faults/cpu-8  510728.2754 (  0.00%)  510598.8214 ( -0.03%)
Hmean    faults/sec-1 1432084.7845 (  0.00%) 1497935.5274 (  4.60%)
Hmean    faults/sec-3 3943818.1437 (  0.00%) 3941920.1520 ( -0.05%)
Hmean    faults/sec-5 3877573.5867 (  0.00%) 3869385.7553 ( -0.21%)
Hmean    faults/sec-7 3991832.0418 (  0.00%) 3992181.4189 (  0.01%)
Hmean    faults/sec-8 3987189.8167 (  0.00%) 3986452.2204 ( -0.02%)

It's only visible at single threaded. The overhead is there for higher
threads but other factors dominate.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agohugetlb: do not account hugetlb pages as NR_FILE_PAGES
Michal Hocko [Wed, 24 Jun 2015 23:57:24 +0000 (16:57 -0700)]
hugetlb: do not account hugetlb pages as NR_FILE_PAGES

hugetlb pages uses add_to_page_cache to track shared mappings.  This is
OK from the data structure point of view but it is less so from the
NR_FILE_PAGES accounting:

- huge pages are accounted as 4k which is clearly wrong
- this counter is used as the amount of the reclaimable page
  cache which is incorrect as well because hugetlb pages are
  special and not reclaimable
- the counter is then exported to userspace via /proc/meminfo
  (in Cached:), /proc/vmstat and /proc/zoneinfo as
  nr_file_pages which is confusing at least:
  Cached:          8883504 kB
  HugePages_Free:     8348
  ...
  Cached:          8916048 kB
  HugePages_Free:      156
  ...
  thats 8192 huge pages allocated which is ~16G accounted as 32M

There are usually not that many huge pages in the system for this to
make any visible difference e.g.  by fooling __vm_enough_memory or
zone_pagecache_reclaimable.

Fix this by special casing huge pages in both __delete_from_page_cache
and __add_to_page_cache_locked.  replace_page_cache_page is currently
only used by fuse and that shouldn't touch hugetlb pages AFAICS but it
is more robust to check for special casing there as well.

Hugetlb pages shouldn't get to any other paths where we do accounting:
- migration - we have a special handling via
  hugetlbfs_migrate_page
- shmem - doesn't handle hugetlb pages directly even for
  SHM_HUGETLB resp. MAP_HUGETLB
- swapcache - hugetlb is not swapable

This has a user visible effect but I believe it is reasonable because the
previously exported number is simply bogus.

An alternative would be to account hugetlb pages with their real size and
treat them similar to shmem.  But this has some drawbacks.

First we would have to special case in kernel users of NR_FILE_PAGES and
considering how hugetlb is special we would have to do it everywhere.  We
do not want Cached exported by /proc/meminfo to include it because the
value would be even more misleading.

__vm_enough_memory and zone_pagecache_reclaimable would have to do the
same thing because those pages are simply not reclaimable.  The correction
is even not trivial because we would have to consider all active hugetlb
page sizes properly.  Users of the counter outside of the kernel would
have to do the same.

So the question is why to account something that needs to be basically
excluded for each reasonable usage.  This doesn't make much sense to me.

It seems that this has been broken since hugetlb was introduced but I
haven't checked the whole history.

[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: page_alloc: inline should_alloc_retry()
Johannes Weiner [Wed, 24 Jun 2015 23:57:21 +0000 (16:57 -0700)]
mm: page_alloc: inline should_alloc_retry()

The should_alloc_retry() function was meant to encapsulate retry
conditions of the allocator slowpath, but there are still checks
remaining in the main function, and much of how the retrying is
performed also depends on the OOM killer progress.  The physical
separation of those conditions make the code hard to follow.

Inline the should_alloc_retry() checks.  Notes:

- The __GFP_NOFAIL check is already done in __alloc_pages_may_oom(),
  replace it with looping on OOM killer progress

- The pm_suspended_storage() check is meant to skip the OOM killer
  when reclaim has no IO available, move to __alloc_pages_may_oom()

- The order <= PAGE_ALLOC_COSTLY order is re-united with its original
  counterpart of checking whether reclaim actually made any progress

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: oom_kill: simplify OOM killer locking
Johannes Weiner [Wed, 24 Jun 2015 23:57:19 +0000 (16:57 -0700)]
mm: oom_kill: simplify OOM killer locking

The zonelist locking and the oom_sem are two overlapping locks that are
used to serialize global OOM killing against different things.

The historical zonelist locking serializes OOM kills from allocations with
overlapping zonelists against each other to prevent killing more tasks
than necessary in the same memory domain.  Only when neither tasklists nor
zonelists from two concurrent OOM kills overlap (tasks in separate memcgs
bound to separate nodes) are OOM kills allowed to execute in parallel.

The younger oom_sem is a read-write lock to serialize OOM killing against
the PM code trying to disable the OOM killer altogether.

However, the OOM killer is a fairly cold error path, there is really no
reason to optimize for highly performant and concurrent OOM kills.  And
the oom_sem is just flat-out redundant.

Replace both locking schemes with a single global mutex serializing OOM
kills regardless of context.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: oom_kill: remove unnecessary locking in exit_oom_victim()
Johannes Weiner [Wed, 24 Jun 2015 23:57:16 +0000 (16:57 -0700)]
mm: oom_kill: remove unnecessary locking in exit_oom_victim()

Disabling the OOM killer needs to exclude allocators from entering, not
existing victims from exiting.

Right now the only waiter is suspend code, which achieves quiescence by
disabling the OOM killer.  But later on we want to add waits that hold
the lock instead to stop new victims from showing up.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: oom_kill: generalize OOM progress waitqueue
Johannes Weiner [Wed, 24 Jun 2015 23:57:13 +0000 (16:57 -0700)]
mm: oom_kill: generalize OOM progress waitqueue

It turns out that the mechanism to wait for exiting OOM victims is less
generic than it looks: it won't issue wakeups unless the OOM killer is
disabled.

The reason this check was added was the thought that, since only the OOM
disabling code would wait on this queue, wakeup operations could be
saved when that specific consumer is known to be absent.

However, this is quite the handgrenade.  Later attempts to reuse the
waitqueue for other purposes will lead to completely unexpected bugs and
the failure mode will appear seemingly illogical.  Generally, providers
shouldn't make unnecessary assumptions about consumers.

This could have been replaced with waitqueue_active(), but it only saves
a few instructions in one of the coldest paths in the kernel.  Simply
remove it.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: oom_kill: switch test-and-clear of known TIF_MEMDIE to clear
Johannes Weiner [Wed, 24 Jun 2015 23:57:10 +0000 (16:57 -0700)]
mm: oom_kill: switch test-and-clear of known TIF_MEMDIE to clear

exit_oom_victim() already knows that TIF_MEMDIE is set, and nobody else
can clear it concurrently.  Use clear_thread_flag() directly.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: oom_kill: clean up victim marking and exiting interfaces
Johannes Weiner [Wed, 24 Jun 2015 23:57:07 +0000 (16:57 -0700)]
mm: oom_kill: clean up victim marking and exiting interfaces

Rename unmark_oom_victim() to exit_oom_victim().  Marking and unmarking
are related in functionality, but the interface is not symmetrical at
all: one is an internal OOM killer function used during the killing, the
other is for an OOM victim to signal its own death on exit later on.
This has locking implications, see follow-up changes.

While at it, rename mark_tsk_oom_victim() to mark_oom_victim(), which
is easier on the eye.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: oom_kill: remove unnecessary locking in oom_enable()
Johannes Weiner [Wed, 24 Jun 2015 23:57:04 +0000 (16:57 -0700)]
mm: oom_kill: remove unnecessary locking in oom_enable()

Setting oom_killer_disabled to false is atomic, there is no need for
further synchronization with ongoing allocations trying to OOM-kill.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/memory hotplug: init the zone's size when calculating node totalpages
Gu Zheng [Wed, 24 Jun 2015 23:57:02 +0000 (16:57 -0700)]
mm/memory hotplug: init the zone's size when calculating node totalpages

Init the zone's size when calculating node totalpages to avoid duplicated
operations in free_area_init_core().

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/hugetlb: introduce minimum hugepage order
Naoya Horiguchi [Wed, 24 Jun 2015 23:56:59 +0000 (16:56 -0700)]
mm/hugetlb: introduce minimum hugepage order

Currently the initial value of order in dissolve_free_huge_page is 64 or
32, which leads to the following warning in static checker:

  mm/hugetlb.c:1203 dissolve_free_huge_pages()
  warn: potential right shift more than type allows '9,18,64'

This is a potential risk of infinite loop, because 1 << order (== 0) is used
in for-loop like this:

  for (pfn =3D start_pfn; pfn < end_pfn; pfn +=3D 1 << order)
      ...

So this patch fixes it by using global minimum_order calculated at boot time.

    text    data     bss     dec     hex filename
   28313     469   84236  113018   1b97a mm/hugetlb.o
   28256     473   84236  112965   1b945 mm/hugetlb.o (patched)

Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agormap: fix theoretical race between do_wp_page and shrink_active_list
Vladimir Davydov [Wed, 24 Jun 2015 23:56:56 +0000 (16:56 -0700)]
rmap: fix theoretical race between do_wp_page and shrink_active_list

As noted by Paul the compiler is free to store a temporary result in a
variable on stack, heap or global unless it is explicitly marked as
volatile, see:

  http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4455.html#sample-optimizations

This can result in a race between do_wp_page() and shrink_active_list()
as follows.

In do_wp_page() we can call page_move_anon_rmap(), which sets
page->mapping as follows:

  anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
  page->mapping = (struct address_space *) anon_vma;

The page in question may be on an LRU list, because nowhere in
do_wp_page() we remove it from the list, neither do we take any LRU
related locks.  Although the page is locked, shrink_active_list() can
still call page_referenced() on it concurrently, because the latter does
not require an anonymous page to be locked:

  CPU0                          CPU1
  ----                          ----
  do_wp_page                    shrink_active_list
   lock_page                     page_referenced
                                  PageAnon->yes, so skip trylock_page
   page_move_anon_rmap
    page->mapping = anon_vma
                                  rmap_walk
                                   PageAnon->no
                                   rmap_walk_file
                                    BUG
    page->mapping += PAGE_MAPPING_ANON

This patch fixes this race by explicitly forbidding the compiler to split
page->mapping store in page_move_anon_rmap() with the aid of WRITE_ONCE.

[akpm@linux-foundation.org: tweak comment, per Minchan]
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.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>
9 years agomm/memory-failure: me_huge_page() does nothing for thp
Naoya Horiguchi [Wed, 24 Jun 2015 23:56:53 +0000 (16:56 -0700)]
mm/memory-failure: me_huge_page() does nothing for thp

memory_failure() is supposed not to handle thp itself, but to split it.
But if something were wrong and page_action() were called on thp,
me_huge_page() (action routine for hugepages) should be better to take
no action, rather than to take wrong action prepared for hugetlb (which
triggers BUG_ON().)

This change is for potential problems, but makes sense to me because thp
is an actively developing feature and this code path can be open in the
future.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: soft-offline: don't free target page in successful page migration
Naoya Horiguchi [Wed, 24 Jun 2015 23:56:50 +0000 (16:56 -0700)]
mm: soft-offline: don't free target page in successful page migration

Stress testing showed that soft offline events for a process iterating
"mmap-pagefault-munmap" loop can trigger
VM_BUG_ON(PAGE_FLAGS_CHECK_AT_PREP) in __free_one_page():

  Soft offlining page 0x70fe1 at 0x70100008d000
  Soft offlining page 0x705fb at 0x70300008d000
  page:ffffea0001c3f840 count:0 mapcount:0 mapping:          (null) index:0x2
  flags: 0x1fffff80800000(hwpoison)
  page dumped because: VM_BUG_ON_PAGE(page->flags & ((1 << 25) - 1))
  ------------[ cut here ]------------
  kernel BUG at /src/linux-dev/mm/page_alloc.c:585!
  invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
  Modules linked in: cfg80211 rfkill crc32c_intel microcode ppdev parport_pc pcspkr serio_raw virtio_balloon parport i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi floppy
  CPU: 3 PID: 1779 Comm: test_base_madv_ Not tainted 4.0.0-v4.0-150511-1451-00009-g82360a3730e6 #139
  RIP: free_pcppages_bulk+0x52a/0x6f0
  Call Trace:
    drain_pages_zone+0x3d/0x50
    drain_local_pages+0x1d/0x30
    on_each_cpu_mask+0x46/0x80
    drain_all_pages+0x14b/0x1e0
    soft_offline_page+0x432/0x6e0
    SyS_madvise+0x73c/0x780
    system_call_fastpath+0x12/0x17
  Code: ff 89 45 b4 48 8b 45 c0 48 83 b8 a8 00 00 00 00 0f 85 e3 fb ff ff 0f 1f 00 0f 0b 48 8b 7d 90 48 c7 c6 e8 95 a6 81 e8 e6 32 02 00 <0f> 0b 8b 45 cc 49 89 47 30 41 8b 47 18 83 f8 ff 0f 85 10 ff ff
  RIP  [<ffffffff811a806a>] free_pcppages_bulk+0x52a/0x6f0
   RSP <ffff88007a117d28>
  ---[ end trace 53926436e76d1f35 ]---

When soft offline successfully migrates page, the source page is supposed
to be freed.  But there is a race condition where a source page looks
isolated (i.e.  the refcount is 0 and the PageHWPoison is set) but
somewhat linked to pcplist.  Then another soft offline event calls
drain_all_pages() and tries to free such hwpoisoned page, which is
forbidden.

This odd page state seems to happen due to the race between put_page() in
putback_lru_page() and __pagevec_lru_add_fn().  But I don't want to play
with tweaking drain code as done in commit 9ab3b598d2df "mm: hwpoison:
drop lru_add_drain_all() in __soft_offline_page()", or to change page
freeing code for this soft offline's purpose.

Instead, let's think about the difference between hard offline and soft
offline.  There is an interesting difference in how to isolate the in-use
page between these, that is, hard offline marks PageHWPoison of the target
page at first, and doesn't free it by keeping its refcount 1.  OTOH, soft
offline tries to free the target page then marks PageHWPoison.  This
difference might be the source of complexity and result in bugs like the
above.  So making soft offline isolate with keeping refcount can be a
solution for this problem.

We can pass to page migration code the "reason" which shows the caller, so
let's use this more to avoid calling putback_lru_page() when called from
soft offline, which effectively does the isolation for soft offline.  With
this change, target pages of soft offline never be reused without changing
migratetype, so this patch also removes the related code.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/memory-failure: introduce get_hwpoison_page() for consistent refcount handling
Naoya Horiguchi [Wed, 24 Jun 2015 23:56:48 +0000 (16:56 -0700)]
mm/memory-failure: introduce get_hwpoison_page() for consistent refcount handling

memory_failure() can run in 2 different mode (specified by
MF_COUNT_INCREASED) in page refcount perspective.  When
MF_COUNT_INCREASED is set, memory_failure() assumes that the caller
takes a refcount of the target page.  And if cleared, memory_failure()
takes it in it's own.

In current code, however, refcounting is done differently in each caller.
For example, madvise_hwpoison() uses get_user_pages_fast() and
hwpoison_inject() uses get_page_unless_zero().  So this inconsistent
refcounting causes refcount failure especially for thp tail pages.
Typical user visible effects are like memory leak or
VM_BUG_ON_PAGE(!page_count(page)) in isolate_lru_page().

To fix this refcounting issue, this patch introduces get_hwpoison_page()
to handle thp tail pages in the same manner for each caller of hwpoison
code.

memory_failure() might fail to split thp and in such case it returns
without completing page isolation.  This is not good because PageHWPoison
on the thp is still set and there's no easy way to unpoison such thps.  So
this patch try to roll back any action to the thp in "non anonymous thp"
case and "thp split failed" case, expecting an MCE(SRAR) generated by
later access afterward will properly free such thps.

[akpm@linux-foundation.org: fix CONFIG_HWPOISON_INJECT=m]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/memory-failure: split thp earlier in memory error handling
Naoya Horiguchi [Wed, 24 Jun 2015 23:56:45 +0000 (16:56 -0700)]
mm/memory-failure: split thp earlier in memory error handling

memory_failure() doesn't handle thp itself at this time and need to split
it before doing isolation.  Currently thp is split in the middle of
hwpoison_user_mappings(), but there're corner cases where memory_failure()
wrongly tries to handle thp without splitting.

1) "non anonymous" thp, which is not a normal operating mode of thp,
   but a memory error could hit a thp before anon_vma is initialized.  In
   such case, split_huge_page() fails and me_huge_page() (intended for
   hugetlb) is called for thp, which triggers BUG_ON in page_hstate().

2) !PageLRU case, where hwpoison_user_mappings() returns with
   SWAP_SUCCESS and the result is the same as case 1.

memory_failure() can't avoid splitting, so let's split it more earlier,
which also reduces code which are prepared for both of normal page and
thp.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: rename RECLAIM_SWAP to RECLAIM_UNMAP
Zhihui Zhang [Wed, 24 Jun 2015 23:56:42 +0000 (16:56 -0700)]
mm: rename RECLAIM_SWAP to RECLAIM_UNMAP

The name SWAP implies that we are dealing with anonymous pages only.  In
fact, the original patch that introduced the min_unmapped_ratio logic
was to fix an issue related to file pages.  Rename it to RECLAIM_UNMAP
to match what does.

Historically, commit a6dc60f8975a ("vmscan: rename sc.may_swap to
may_unmap") renamed .may_swap to .may_unmap, leaving RECLAIM_SWAP
behind.  commit 2e2e42598908 ("vmscan,memcg: reintroduce sc->may_swap")
reintroduced .may_swap for memory controller.

Signed-off-by: Zhihui Zhang <zzhsuny@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: vmscan: do not throttle based on pfmemalloc reserves if node has no reclaimable...
Nishanth Aravamudan [Wed, 24 Jun 2015 23:56:39 +0000 (16:56 -0700)]
mm: vmscan: do not throttle based on pfmemalloc reserves if node has no reclaimable pages

Based upon 675becce15 ("mm: vmscan: do not throttle based on pfmemalloc
reserves if node has no ZONE_NORMAL") from Mel.

We have a system with the following topology:

# numactl -H
available: 3 nodes (0,2-3)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
23 24 25 26 27 28 29 30 31
node 0 size: 28273 MB
node 0 free: 27323 MB
node 2 cpus:
node 2 size: 16384 MB
node 2 free: 0 MB
node 3 cpus: 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
node 3 size: 30533 MB
node 3 free: 13273 MB
node distances:
node   0   2   3
  0:  10  20  20
  2:  20  10  20
  3:  20  20  10

Node 2 has no free memory, because:
# cat /sys/devices/system/node/node2/hugepages/hugepages-16777216kB/nr_hugepages
1

This leads to the following zoneinfo:

Node 2, zone      DMA
  pages free     0
        min      1840
        low      2300
        high     2760
        scanned  0
        spanned  262144
        present  262144
        managed  262144
...
  all_unreclaimable: 1

If one then attempts to allocate some normal 16M hugepages via

echo 37 > /proc/sys/vm/nr_hugepages

The echo never returns and kswapd2 consumes CPU cycles.

This is because throttle_direct_reclaim ends up calling
wait_event(pfmemalloc_wait, pfmemalloc_watermark_ok...).
pfmemalloc_watermark_ok() in turn checks all zones on the node if there
are any reserves, and if so, then indicates the watermarks are ok, by
seeing if there are sufficient free pages.

675becce15 added a condition already for memoryless nodes.  In this case,
though, the node has memory, it is just all consumed (and not
reclaimable).  Effectively, though, the result is the same on this call to
pfmemalloc_watermark_ok() and thus seems like a reasonable additional
condition.

With this change, the afore-mentioned 16M hugepage allocation attempt
succeeds and correctly round-robins between Nodes 1 and 3.

Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Anton Blanchard <anton@samba.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/page_alloc.c: cleanup obsolete KM_USER*
Anisse Astier [Wed, 24 Jun 2015 23:56:36 +0000 (16:56 -0700)]
mm/page_alloc.c: cleanup obsolete KM_USER*

It's been five years now that KM_* kmap flags have been removed and that
we can call clear_highpage from any context.  So we remove prep_zero_pages
accordingly.

Signed-off-by: Anisse Astier <anisse@astier.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: avoid tail page refcounting on non-THP compound pages
Kirill A. Shutemov [Wed, 24 Jun 2015 23:56:33 +0000 (16:56 -0700)]
mm: avoid tail page refcounting on non-THP compound pages

Reintroduce 8d63d99a5dfb ("mm: avoid tail page refcounting on non-THP
compound pages") after removing bogus VM_BUG_ON_PAGE() in
put_unrefcounted_compound_page().

THP uses tail page refcounting to be able to split huge pages at any time.
 Tail page refcounting is not needed for other users of compound pages and
it's harmful because of overhead.

We try to exclude non-THP pages from tail page refcounting using
__compound_tail_refcounted() check.  It excludes most common non-THP
compound pages: SL*B and hugetlb, but it doesn't catch rest of __GFP_COMP
users -- drivers.

And it's not only about overhead.

Drivers might want to use compound pages to get refcounting semantics
suitable for mapping high-order pages to userspace.  But tail page
refcounting breaks it.

Tail page refcounting uses ->_mapcount in tail pages to store GUP pins on
them.  It means GUP pins would affect page_mapcount() for tail pages.
It's not a problem for THP, because it never maps tail pages.  But unlike
THP, drivers map parts of compound pages with PTEs and it makes
page_mapcount() be called for tail pages.

In particular, GUP pins would shift PSS up and affect /proc/kpagecount for
such pages.  But, I'm not aware about anything which can lead to crash or
other serious misbehaviour.

Since currently all THP pages are anonymous and all drivers pages are not,
we can fix the __compound_tail_refcounted() check by requiring PageAnon()
to enable tail page refcounting.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: drop bogus VM_BUG_ON_PAGE assert in put_page() codepath
Kirill A. Shutemov [Wed, 24 Jun 2015 23:56:30 +0000 (16:56 -0700)]
mm: drop bogus VM_BUG_ON_PAGE assert in put_page() codepath

My commit 8d63d99a5dfb ("mm: avoid tail page refcounting on non-THP
compound pages") which was merged during 4.1 merge window caused
regression:

  page:ffffea0010a15040 count:0 mapcount:1 mapping:          (null) index:0x0
  flags: 0x8000000000008014(referenced|dirty|tail)
  page dumped because: VM_BUG_ON_PAGE(page_mapcount(page) != 0)
  ------------[ cut here ]------------
  kernel BUG at mm/swap.c:134!

The problem can be reproduced by playing *two* audio files at the same
time and then stopping one of players.  I used two mplayers to trigger
this.

The VM_BUG_ON_PAGE() which triggers the bug is bogus:

Sound subsystem uses compound pages for its buffers, but unlike most
__GFP_COMP sound maps compound pages to userspace with PTEs.

In our case with two players map the buffer twice and therefore elevates
page_mapcount() on tail pages by two.  When one of players exits it
unmaps the VMA and drops page_mapcount() to one and try to release
reference on the page with put_page().

My commit changes which path it takes under put_compound_page().  It hits
put_unrefcounted_compound_page() where VM_BUG_ON_PAGE() is.  It sees
page_mapcount() == 1.  The function wrongly assumes that subpages of
compound page cannot be be mapped by itself with PTEs..

The solution is simply drop the VM_BUG_ON_PAGE().

Note: there's no need to move the check under put_page_testzero().
Allocator will check the mapcount by itself before putting on free list.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: only define hashdist variable when needed
Rasmus Villemoes [Wed, 24 Jun 2015 23:56:28 +0000 (16:56 -0700)]
mm: only define hashdist variable when needed

For !CONFIG_NUMA, hashdist will always be 0, since it's setter is
otherwise compiled out.  So we can save 4 bytes of data and some .text
(although mostly in __init functions) by only defining it for
CONFIG_NUMA.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/hugetlb: reduce arch dependent code about hugetlb_prefault_arch_hook
Zhang Zhen [Wed, 24 Jun 2015 23:56:25 +0000 (16:56 -0700)]
mm/hugetlb: reduce arch dependent code about hugetlb_prefault_arch_hook

Currently we have many duplicates in definitions of
hugetlb_prefault_arch_hook.  In all architectures this function is empty.

Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agopowerpc/mm: tracking vDSO remap
Laurent Dufour [Wed, 24 Jun 2015 23:56:22 +0000 (16:56 -0700)]
powerpc/mm: tracking vDSO remap

Some processes (CRIU) are moving the vDSO area using the mremap system
call.  As a consequence the kernel reference to the vDSO base address is
no more valid and the signal return frame built once the vDSO has been
moved is not pointing to the new sigreturn address.

This patch handles vDSO remapping and unmapping.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: new arch_remap() hook
Laurent Dufour [Wed, 24 Jun 2015 23:56:19 +0000 (16:56 -0700)]
mm: new arch_remap() hook

Some architectures would like to be triggered when a memory area is moved
through the mremap system call.

This patch introduces a new arch_remap() mm hook which is placed in the
path of mremap, and is called before the old area is unmapped (and the
arch_unmap() hook is called).

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: new mm hook framework
Laurent Dufour [Wed, 24 Jun 2015 23:56:16 +0000 (16:56 -0700)]
mm: new mm hook framework

CRIU is recreating the process memory layout by remapping the checkpointee
memory area on top of the current process (criu).  This includes remapping
the vDSO to the place it has at checkpoint time.

However some architectures like powerpc are keeping a reference to the
vDSO base address to build the signal return stack frame by calling the
vDSO sigreturn service.  So once the vDSO has been moved, this reference
is no more valid and the signal frame built later are not usable.

This patch serie is introducing a new mm hook framework, and a new
arch_remap hook which is called when mremap is done and the mm lock still
hold.  The next patch is adding the vDSO remap and unmap tracking to the
powerpc architecture.

This patch (of 3):

This patch introduces a new set of header file to manage mm hooks:
- per architecture empty header file (arch/x/include/asm/mm-arch-hooks.h)
- a generic header (include/linux/mm-arch-hooks.h)

The architecture which need to overwrite a hook as to redefine it in its
header file, while architecture which doesn't need have nothing to do.

The default hooks are defined in the generic header and are used in the
case the architecture is not defining it.

In a next step, mm hooks defined in include/asm-generic/mm_hooks.h should
be moved here.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm/hugetlb: reduce arch dependent code about huge_pmd_unshare
Zhang Zhen [Wed, 24 Jun 2015 23:56:13 +0000 (16:56 -0700)]
mm/hugetlb: reduce arch dependent code about huge_pmd_unshare

Currently we have many duplicates in definitions of huge_pmd_unshare.  In
all architectures this function just returns 0 when
CONFIG_ARCH_WANT_HUGE_PMD_SHARE is N.

This patch puts the default implementation in mm/hugetlb.c and lets these
architectures use the common code.

Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: David Rientjes <rientjes@google.com>
Cc: James Yang <James.Yang@freescale.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm: fix mprotect() behaviour on VM_LOCKED VMAs
Kirill A. Shutemov [Wed, 24 Jun 2015 23:56:10 +0000 (16:56 -0700)]
mm: fix mprotect() behaviour on VM_LOCKED VMAs

On mlock(2) we trigger COW on private writable VMA to avoid faults in
future.

mm/gup.c:
 840 long populate_vma_page_range(struct vm_area_struct *vma,
 841                 unsigned long start, unsigned long end, int *nonblocking)
 842 {
 ...
 855          * We want to touch writable mappings with a write fault in order
 856          * to break COW, except for shared mappings because these don't COW
 857          * and we would not want to dirty them for nothing.
 858          */
 859         if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
 860                 gup_flags |= FOLL_WRITE;

But we miss this case when we make VM_LOCKED VMA writeable via
mprotect(2). The test case:

#define _GNU_SOURCE
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>

#define PAGE_SIZE 4096

int main(int argc, char **argv)
{
struct rusage usage;
long before;
char *p;
int fd;

/* Create a file and populate first page of page cache */
fd = open("/tmp", O_TMPFILE | O_RDWR, S_IRUSR | S_IWUSR);
write(fd, "1", 1);

/* Create a *read-only* *private* mapping of the file */
p = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE, fd, 0);

/*
 * Since the mapping is read-only, mlock() will populate the mapping
 * with PTEs pointing to page cache without triggering COW.
 */
mlock(p, PAGE_SIZE);

/*
 * Mapping became read-write, but it's still populated with PTEs
 * pointing to page cache.
 */
mprotect(p, PAGE_SIZE, PROT_READ | PROT_WRITE);

getrusage(RUSAGE_SELF, &usage);
before = usage.ru_minflt;

/* Trigger COW: fault in mlock()ed VMA. */
*p = 1;

getrusage(RUSAGE_SELF, &usage);
printf("faults: %ld\n", usage.ru_minflt - before);

return 0;
}

$ ./test
faults: 1

Let's fix it by triggering populating of VMA in mprotect_fixup() on this
condition. We don't care about population error as we don't in other
similar cases i.e. mremap.

[akpm@linux-foundation.org: tweak comment text]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agothp: cleanup how khugepaged enters freezer
Jiri Kosina [Wed, 24 Jun 2015 23:56:07 +0000 (16:56 -0700)]
thp: cleanup how khugepaged enters freezer

khugepaged_do_scan() checks in every iteration whether freezing(current)
is true, and in such case breaks out of the loop, which causes
try_to_freeze() to be called immediately afterwards in
khugepaged_wait_work().

If nothing else, this causes unnecessary freezing(current) test, and also
makes the way khugepaged enters freezer a bit less obvious than necessary.

Let's just try to freeze directly, instead of splitting it into two
(directly adjacent) phases.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm, hwpoison: remove obsolete "Notebook" todo list
Andi Kleen [Wed, 24 Jun 2015 23:56:05 +0000 (16:56 -0700)]
mm, hwpoison: remove obsolete "Notebook" todo list

All the items mentioned here have been either addressed, or were not
really needed.  So just remove the comment.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agomm, hwpoison: add comment describing when to add new cases
Andi Kleen [Wed, 24 Jun 2015 23:56:02 +0000 (16:56 -0700)]
mm, hwpoison: add comment describing when to add new cases

Here's another comment fix for hwpoison.

It describes the "guiding principle" on when to add new
memory error recovery code.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agolinux/slab.h: fix three off-by-one typos in comment
Rasmus Villemoes [Wed, 24 Jun 2015 23:55:59 +0000 (16:55 -0700)]
linux/slab.h: fix three off-by-one typos in comment

The first is a keyboard-off-by-one, the other two the ordinary mathy kind.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoslab: correct size_index table before replacing the bootstrap kmem_cache_node
Daniel Sanders [Wed, 24 Jun 2015 23:55:57 +0000 (16:55 -0700)]
slab: correct size_index table before replacing the bootstrap kmem_cache_node

This patch moves the initialization of the size_index table slightly
earlier so that the first few kmem_cache_node's can be safely allocated
when KMALLOC_MIN_SIZE is large.

There are currently two ways to generate indices into kmalloc_caches (via
kmalloc_index() and via the size_index table in slab_common.c) and on some
arches (possibly only MIPS) they potentially disagree with each other
until create_kmalloc_caches() has been called.  It seems that the
intention is that the size_index table is a fast equivalent to
kmalloc_index() and that create_kmalloc_caches() patches the table to
return the correct value for the cases where kmalloc_index()'s
if-statements apply.

The failing sequence was:
* kmalloc_caches contains NULL elements
* kmem_cache_init initialises the element that 'struct
  kmem_cache_node' will be allocated to. For 32-bit Mips, this is a
  56-byte struct and kmalloc_index returns KMALLOC_SHIFT_LOW (7).
* init_list is called which calls kmalloc_node to allocate a 'struct
  kmem_cache_node'.
* kmalloc_slab selects the kmem_caches element using
  size_index[size_index_elem(size)]. For MIPS, size is 56, and the
  expression returns 6.
* This element of kmalloc_caches is NULL and allocation fails.
* If it had not already failed, it would have called
  create_kmalloc_caches() at this point which would have changed
  size_index[size_index_elem(size)] to 7.

I don't believe the bug to be LLVM specific but GCC doesn't normally
encounter the problem.  I haven't been able to identify exactly what GCC
is doing better (probably inlining) but it seems that GCC is managing to
optimize to the point that it eliminates the problematic allocations.
This theory is supported by the fact that GCC can be made to fail in the
same way by changing inline, __inline, __inline__, and __always_inline in
include/linux/compiler-gcc.h such that they don't actually inline things.

Signed-off-by: Daniel Sanders <daniel.sanders@imgtec.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.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>
9 years agomm/slab_common: support the slub_debug boot option on specific object size
Gavin Guo [Wed, 24 Jun 2015 23:55:54 +0000 (16:55 -0700)]
mm/slab_common: support the slub_debug boot option on specific object size

The slub_debug=PU,kmalloc-xx cannot work because in the
create_kmalloc_caches() the s->name is created after the
create_kmalloc_cache() is called.  The name is NULL in the
create_kmalloc_cache() so the kmem_cache_flags() would not set the
slub_debug flags to the s->flags.  The fix here set up a kmalloc_names
string array for the initialization purpose and delete the dynamic name
creation of kmalloc_caches.

[akpm@linux-foundation.org: s/kmalloc_names/kmalloc_info/, tweak comment text]
Signed-off-by: Gavin Guo <gavin.guo@canonical.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.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>
9 years agoxtensa: use for_each_sg()
Akinobu Mita [Wed, 24 Jun 2015 23:55:51 +0000 (16:55 -0700)]
xtensa: use for_each_sg()

This replaces the plain loop over the sglist array with for_each_sg()
macro which consists of sg_next() function calls.  Since xtensa doesn't
select ARCH_HAS_SG_CHAIN, it is not necessary to use for_each_sg() in
order to loop over each sg element.  But this can help find problems
with drivers that do not properly initialize their sg tables when
CONFIG_DEBUG_SG is enabled.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoprocfs: treat parked tasks as sleeping for task state
Chris Metcalf [Wed, 24 Jun 2015 23:55:48 +0000 (16:55 -0700)]
procfs: treat parked tasks as sleeping for task state

Allowing watchdog threads to be parked means that we now have the
opportunity of actually seeing persistent parked threads in the output
of /proc/<pid>/stat and /proc/<pid>/status.  The existing code reported
such threads as "Running", which is kind-of true if you think of the
case where we park them as part of taking cpus offline.  But if we allow
parking them indefinitely, "Running" is pretty misleading, so we report
them as "Sleeping" instead.

We could simply report them with a new string, "Parked", but it feels
like it's a bit risky for userspace to see unexpected new values; the
output is already documented in Documentation/filesystems/proc.txt, and
it seems like a mistake to change that lightly.

The scheduler does report parked tasks with a "P" in debugging output
from sched_show_task() or dump_cpu_task(), but that's a different API.
Similarly, the trace_ctxwake_* routines report a "P" for parked tasks,
but again, different API.

This change seemed slightly cleaner than updating the task_state_array
to have additional rows.  TASK_DEAD should be subsumed by the exit_state
bits; TASK_WAKEKILL is just a modifier; and TASK_WAKING can very
reasonably be reported as "Running" (as it is now).  Only TASK_PARKED
shows up with unreasonable output here.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agowatchdog: add watchdog_cpumask sysctl to assist nohz
Chris Metcalf [Wed, 24 Jun 2015 23:55:45 +0000 (16:55 -0700)]
watchdog: add watchdog_cpumask sysctl to assist nohz

Change the default behavior of watchdog so it only runs on the
housekeeping cores when nohz_full is enabled at build and boot time.
Allow modifying the set of cores the watchdog is currently running on
with a new kernel.watchdog_cpumask sysctl.

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

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

[jhubbard@nvidia.com: fix a watchdog crash in some configurations]
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agosmpboot: allow excluding cpus from the smpboot threads
Chris Metcalf [Wed, 24 Jun 2015 23:55:42 +0000 (16:55 -0700)]
smpboot: allow excluding cpus from the smpboot threads

This patch series allows the watchdog to run by default only on the
housekeeping cores when nohz_full is in effect; this seems to be a good
compromise short of turning it off completely (since the nohz_full cores
can't tolerate a watchdog).

To provide customizability, we add /proc/sys/kernel/watchdog_cpumask so
that the set of cores running the watchdog can be tuned to different
values after bootup.

To implement this customizability, we add a new
smpboot_update_cpumask_percpu_thread() API to the smpboot_thread
subsystem that lets us park or unpark "unwanted" threads.

And now that threads can be parked for long periods of time, we tweak the
/proc/<pid>/stat and /proc/<pid>/status code so parked threads aren't
reported as running, which is otherwise confusing.

This patch (of 3):

This change allows some cores to be excluded from running the
smp_hotplug_thread tasks.  The following commit to update
kernel/watchdog.c to use this functionality is the motivating example, and
more information on the motivation is provided there.

A new smp_hotplug_thread field is introduced, "cpumask", which is cpumask
field managed by the smpboot subsystem that indicates whether or not the
given smp_hotplug_thread should run on that core; the cpumask is checked
when deciding whether to unpark the thread.

To limit the cpumask to less than cpu_possible, you must call
smpboot_update_cpumask_percpu_thread() after registering.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agosparc: use for_each_sg()
Akinobu Mita [Wed, 24 Jun 2015 23:55:40 +0000 (16:55 -0700)]
sparc: use for_each_sg()

This replaces the plain loop over the sglist array with for_each_sg()
macro which consists of sg_next() function calls.  Since sparc does select
ARCH_HAS_SG_CHAIN, it is necessary to use for_each_sg() in order to loop
over each sg element.  This also help find problems with drivers that do
not properly initialize their sg tables when CONFIG_DEBUG_SG is enabled.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoparisc: use for_each_sg()
Akinobu Mita [Wed, 24 Jun 2015 23:55:37 +0000 (16:55 -0700)]
parisc: use for_each_sg()

This replaces the plain loop over the sglist array with for_each_sg()
macro which consists of sg_next() function calls.  Since parisc doesn't
select ARCH_HAS_SG_CHAIN, it is not necessary to use for_each_sg() in
order to loop over each sg element.  But this can help find problems with
drivers that do not properly initialize their sg tables when
CONFIG_DEBUG_SG is enabled.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: mark local functions as static
Joseph Qi [Wed, 24 Jun 2015 23:55:34 +0000 (16:55 -0700)]
ocfs2: mark local functions as static

Some functions are only used locally, so mark them as static.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: use swap() in ocfs2_double_lock()
Fabian Frederick [Wed, 24 Jun 2015 23:55:31 +0000 (16:55 -0700)]
ocfs2: use swap() in ocfs2_double_lock()

Use kernel.h macro definition.

Thanks to Julia Lawall for Coccinelle scripting support.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: use swap() in swap_refcount_rec()
Fabian Frederick [Wed, 24 Jun 2015 23:55:29 +0000 (16:55 -0700)]
ocfs2: use swap() in swap_refcount_rec()

Use kernel.h macro definition.

Thanks to Julia Lawall for Coccinelle scripting support.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: use swap() in dx_leaf_sort_swap()
Fabian Frederick [Wed, 24 Jun 2015 23:55:26 +0000 (16:55 -0700)]
ocfs2: use swap() in dx_leaf_sort_swap()

Use kernel.h macro definition.

Thanks to Julia Lawall for Coccinelle scripting support.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: fix wrong check in ocfs2_direct_IO_get_blocks
Joseph Qi [Wed, 24 Jun 2015 23:55:23 +0000 (16:55 -0700)]
ocfs2: fix wrong check in ocfs2_direct_IO_get_blocks

contig_blocks gotten from ocfs2_extent_map_get_blocks cannot be compared
with clusters_to_alloc. So convert it to clusters first.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Reviewed-by: Weiwei Wang <wangww631@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: fix NULL pointer dereference in function ocfs2_abort_trigger()
Xue jiufei [Wed, 24 Jun 2015 23:55:20 +0000 (16:55 -0700)]
ocfs2: fix NULL pointer dereference in function ocfs2_abort_trigger()

ocfs2_abort_trigger() use bh->b_assoc_map to get sb.  But there's no
function to set bh->b_assoc_map in ocfs2, it will trigger NULL pointer
dereference while calling this function.  We can get sb from
bh->b_bdev->bd_super instead of b_assoc_map.

[akpm@linux-foundation.org: update comment, per Joseph]
Signed-off-by: joyce.xue <xuejiufei@huawei.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: o2net: should remove debugfs in o2net_init() out branch
alex chen [Wed, 24 Jun 2015 23:55:18 +0000 (16:55 -0700)]
ocfs2: o2net: should remove debugfs in o2net_init() out branch

Signed-off-by: Alex Chen <alex.chen@huawei.com>
Reviewed-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: remove OCFS2_IOCB_SEM lock type in direct io
WeiWei Wang [Wed, 24 Jun 2015 23:55:15 +0000 (16:55 -0700)]
ocfs2: remove OCFS2_IOCB_SEM lock type in direct io

In ocfs2 direct read/write, OCFS2_IOCB_SEM lock type is used to protect
inode->i_alloc_sem rw semaphore lock in the earlier kernel version.
However, in the latest kernel, inode->i_alloc_sem rw semaphore lock is not
used at all, so OCFS2_IOCB_SEM lock type needs to be removed.

Signed-off-by: Weiwei Wang <wangww631@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: do not BUG if jbd2_journal_dirty_metadata fails
Joseph Qi [Wed, 24 Jun 2015 23:55:12 +0000 (16:55 -0700)]
ocfs2: do not BUG if jbd2_journal_dirty_metadata fails

jbd2_journal_dirty_metadata may fail.  Currently it cannot take care of
non zero return value and just BUG in ocfs2_journal_dirty.  This patch is
aborting the handle and journal instead of BUG.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: joyce.xue <xuejiufei@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: remove BUG_ON(!empty_extent) in __ocfs2_rotate_tree_left()
Xue jiufei [Wed, 24 Jun 2015 23:55:09 +0000 (16:55 -0700)]
ocfs2: remove BUG_ON(!empty_extent) in __ocfs2_rotate_tree_left()

ocfs2_rotate_tree_left() calls __ocfs2_rotate_tree_left() for left
rotation while non-rightmost path containing an empty extent in the leaf
block.  __ocfs2_rotate_tree_left() returns -EAGAIN if right subtree having an
empty extent and pass the empty_extent_path to caller.  The caller
ocfs2_rotate_tree_left() will restart rotation from the returned path.

It will trigger the BUG_ON(!ocfs2_is_empty_extent) when the et on disk
is as follows:

eb0 is the leaf block of path(say path_a) passed to
ocfs2_rotate_tree_left, which has an empty rec[0].

eb1 is the leaf block of path(say path_b) that just right to path_a, which
has no empty record.

eb2 is the leaf block of path(say path_c) that just right to path_b, which
has an empty rec[0].  And path_c is also the rightmost path.

Now we want to remove the empty rec[0] in eb0:

ocfs2_rotate_tree_left:
  -> call __ocfs2_rotate_tree_left with path_a as its input *path*
    -> call ocfs2_rotate_subtree_left with path_a as its input
       *left_path* and path_b as its input *right_path*. it will move
       rec[0] in eb1 to eb0, and rec[0] in eb0 is not empty now.
    -> continue to call ocfs2_rotate_subtree_left with path_b as its
       input *left_path* and path_c as its input *right_path*, and
       return -EAGAIN because eb2 has an empty rec[0]
  -> call __ocfs2_rotate_tree_left with path_c as it input, rotate all
     records in eb2 to left and return 0.
  -> call __ocfs2_rotate_tree_left with path_a as its input, and triggers
     the BUG_ON(!ocfs2_is_empty_extent) as the rec[0] in eb0 is not empty.

So the BUG_ON() should be removed and return 0 if rec[0] is no longer an
empty extent.

Signed-off-by: joyce.xue <xuejiufei@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2: return error when ocfs2_figure_merge_contig_type() fails
Xue jiufei [Wed, 24 Jun 2015 23:55:07 +0000 (16:55 -0700)]
ocfs2: return error when ocfs2_figure_merge_contig_type() fails

ocfs2_figure_merge_contig_type() still returns CONTIG_NONE when some error
occurs which will cause an unpredictable error.  So return a proper errno
when ocfs2_figure_merge_contig_type() fails.

Signed-off-by: joyce.xue <xuejiufei@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9 years agoocfs2/dlm: cleanup unused function __dlm_wait_on_lockres_flags_set
Joseph Qi [Wed, 24 Jun 2015 23:55:04 +0000 (16:55 -0700)]
ocfs2/dlm: cleanup unused function __dlm_wait_on_lockres_flags_set

__dlm_wait_on_lockres_flags_set() is declared but not implemented and
used.  So remove it.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>