Pull x86 vdso build fix from Peter Anvin:
 "This fixes building the vdso code on older Linux systems, and probably
  some non-Linux systems"

* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, vdso: Use <tools/le_byteshift.h> for littleendian access

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

This reverts commit 3e1a878b.

It came in very late, and already has one reported failure: Sitsofe
reports that the current tree fails to boot on his EeePC, and bisected
it down to this.  Rather than waste time trying to figure out what's
wrong, just revert it.
Reported-by: Sitsofe Wheeler <sitsofe@gmail.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull clock framework updates from Mike Turquette:
 "The clock framework changes for 3.16 are pretty typical: mostly clock
  driver additions and fixes.  There are additions to the clock core
  code for some of the basic types (e.g. the common divider type has
  some fixes and featured added to it).

  One minor annoyance is a last-minute dependency that wasn't handled
  quite right.  Commit ba0fae3b ("clk: berlin: add core clock driver
  for BG2/BG2CD") in this pull request depends on
  include/dt-bindings/clock/berlin2.h, which is already in your tree via
  the arm-soc pull request.  Building for the berlin platform will break
  when the clk tree is built on it's own, but merged into your master
  branch everything should be fine"

* tag 'clk-for-linus-3.16' of git://git.linaro.org/people/mike.turquette/linux: (75 commits)
  mmc: sunxi: Add driver for SD/MMC hosts found on Allwinner sunxi SoCs
  clk: export __clk_round_rate for providers
  clk: versatile: free icst on error return
  clk: qcom: Return error pointers for unimplemented clocks
  clk: qcom: Support msm8974pro global clock control hardware
  clk: qcom: Properly support display clocks on msm8974
  clk: qcom: Support display RCG clocks
  clk: qcom: Return highest rate when round_rate() exceeds plan
  clk: qcom: Fix mmcc-8974's PLL configurations
  clk: qcom: Fix clk_rcg2_is_enabled() check
  clk: berlin: add core clock driver for BG2Q
  clk: berlin: add core clock driver for BG2/BG2CD
  clk: berlin: add driver for BG2x complex divider cells
  clk: berlin: add driver for BG2x simple PLLs
  clk: berlin: add driver for BG2x audio/video PLL
  clk: st: Terminate of match table
  clk/exynos4: Fix compilation warning
  ARM: shmobile: r8a7779: Add clock index macros for DT sources
  clk: divider: Fix overflow in clk_divider_bestdiv
  clk: u300: Terminate of match table
  ...

Pull VFIO updates from Alex Williamson:
 "A handful of VFIO bug fixes for v3.16"

* tag 'vfio-v3.16-rc1' of git://github.com/awilliam/linux-vfio:
  drivers/vfio/pci: Fix wrong MSI interrupt count
  drivers/vfio: Rework offsetofend()
  vfio/iommu_type1: Avoid overflow
  vfio/pci: Fix unchecked return value
  vfio/pci: Fix sizing of DPA and THP express capabilities

Pull crypto updates from Herbert Xu:
 "Here is the crypto update for 3.16:

   - Added test vectors for SHA/AES-CCM/DES-CBC/3DES-CBC.
   - Fixed a number of error-path memory leaks in tcrypt.
   - Fixed error-path memory leak in caam.
   - Removed unnecessary global mutex from mxs-dcp.
   - Added ahash walk interface that can actually be asynchronous.
   - Cleaned up caam error reporting.
   - Allow crypto_user get operation to be used by non-root users.
   - Add support for SSS module on Exynos.
   - Misc fixes"

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6: (60 commits)
  crypto: testmgr - add aead cbc des, des3_ede tests
  crypto: testmgr - Fix DMA-API warning
  crypto: cesa - tfm->__crt_alg->cra_type directly
  crypto: sahara - tfm->__crt_alg->cra_name directly
  crypto: padlock - tfm->__crt_alg->cra_name directly
  crypto: n2 - tfm->__crt_alg->cra_name directly
  crypto: dcp - tfm->__crt_alg->cra_name directly
  crypto: cesa - tfm->__crt_alg->cra_name directly
  crypto: ccp - tfm->__crt_alg->cra_name directly
  crypto: geode - Don't use tfm->__crt_alg->cra_name directly
  crypto: geode - Weed out printk() from probe()
  crypto: geode - Consistently use AES_KEYSIZE_128
  crypto: geode - Kill AES_IV_LENGTH
  crypto: geode - Kill AES_MIN_BLOCK_SIZE
  crypto: mxs-dcp - Remove global mutex
  crypto: hash - Add real ahash walk interface
  hwrng: n2-drv - Introduce the use of the managed version of kzalloc
  crypto: caam - reinitialize keys_fit_inline for decrypt and givencrypt
  crypto: s5p-sss - fix multiplatform build
  hwrng: timeriomem - remove unnecessary OOM messages
  ...

Pull exofs raid6 support from Boaz Harrosh:
 "These simple patches will enable raid6 using the kernel's raid6_pq
  engine for support under exofs and pnfs-objects.

  There is nothing needed to do at exofs and pnfs-obj.  Just fire your
  mkfs.exofs with --raid=6 (that was already supported before) and off
  you go as usual.  The ORE will pick up the new map and will start
  writing two devices of redundancy bits.  The patches are so simple
  because most of the ORE was already for the general raid case, only a
  few bug fixes were needed and the actual wiring into the raid6_pq
  engine"

* 'for-linus' of git://git.open-osd.org/linux-open-osd:
  ore: Support for raid 6
  ore: Remove redundant dev_order(), more cleanups
  ore: (trivial) reformat some code

Pull btrfs fix from Chris Mason:
 "I had this in my 3.16 merge window queue, but it is small and obvious
  enough for 3.15.  I cherry-picked and retested against current rc8"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: send, fix corrupted path strings for long paths

Pull SCSI target fixes from Nicholas Bellinger:
 "Here are the remaining fixes for v3.15.

  This series includes:

   - iser-target fix for ImmediateData exception reference count bug
     (Sagi + nab)
   - iscsi-target fix for MC/S login + potential iser-target MRDSL
     buffer overrun (Santosh + Roland)
   - iser-target fix for v3.15-rc multi network portal shutdown
     regression (nab)
   - target fix for allowing READ_CAPCITY during ALUA Standby access
     state (Chris + nab)
   - target fix for NULL pointer dereference of alua_access_state for
     un-configured devices (Chris + nab)"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  target: Fix alua_access_state attribute OOPs for un-configured devices
  target: Allow READ_CAPACITY opcode in ALUA Standby access state
  iser-target: Fix multi network portal shutdown regression
  iscsi-target: Fix wrong buffer / buffer overrun in iscsi_change_param_value()
  iser-target: Add missing target_put_sess_cmd for ImmedateData failure

Pull x86 fixes from Peter Anvin:
 "A significantly larger than I'd like set of patches for just below the
  wire.  All of these, however, fix real problems.

  The one thing that is genuinely scary in here is the change of SMP
  initialization, but that *does* fix a confirmed hang when booting
  virtual machines.

  There is also a patch to actually do the right thing about not
  offlining a CPU when there are not enough interrupt vectors available
  in the system; the accounting was done incorrectly.  The worst case
  for that patch is that we fail to offline CPUs when we should (the new
  code is strictly more conservative than the old), so is not
  particularly risky.

  Most of the rest is minor stuff; the EFI patches are all about
  exporting correct information to boot loaders and kexec"

* 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: EFI_MIXED should not prohibit loading above 4G
  x86/smpboot: Initialize secondary CPU only if master CPU will wait for it
  x86/smpboot: Log error on secondary CPU wakeup failure at ERR level
  x86: Fix list/memory corruption on CPU hotplug
  x86: irq: Get correct available vectors for cpu disable
  x86/efi: Do not export efi runtime map in case old map
  x86/efi: earlyprintk=efi,keep fix

commit 7d453eee ("x86/efi: Wire up CONFIG_EFI_MIXED") introduced a
regression for the functionality to load kernels above 4G. The relevant
(incorrect) reasoning behind this change can be seen in the commit
message,

  "The xloadflags field in the bzImage header is also updated to reflect
  that the kernel supports both entry points by setting both of
  XLF_EFI_HANDOVER_32 and XLF_EFI_HANDOVER_64 when CONFIG_EFI_MIXED=y.
  XLF_CAN_BE_LOADED_ABOVE_4G is disabled so that the kernel text is
  guaranteed to be addressable with 32-bits."

This is obviously bogus since 32-bit EFI loaders will never place the
kernel above the 4G mark. So this restriction is entirely unnecessary.

But things are worse than that - since we want to encourage people to
always compile with CONFIG_EFI_MIXED=y so that their kernels work out of
the box for both 32-bit and 64-bit firmware, commit 7d453eee
effectively disables XLF_CAN_BE_LOADED_ABOVE_4G completely.

Remove the overzealous and superfluous restriction and restore the
XLF_CAN_BE_LOADED_ABOVE_4G functionality.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1402140380-15377-1-git-send-email-matt@console-pimps.orgSigned-off-by: H. Peter Anvin <hpa@zytor.com>

Merge more updates from Andrew Morton:

 - Most of the rest of MM.

   This includes "mark remap_file_pages syscall as deprecated" but the
   actual "replace remap_file_pages syscall with emulation" is held
   back.  I guess we'll need to work out when to pull the trigger on
   that one.

 - various minor cleanups to obscure filesystems

 - the drivers/rtc queue

 - hfsplus updates

 - ufs, hpfs, fatfs, affs, reiserfs

 - Documentation/

 - signals

 - procfs

 - cpu hotplug

 - lib/idr.c

 - rapidio

 - sysctl

 - ipc updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (171 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

Commit 788257d6 ("ufs: remove the BKL") replaced BKL with mutex
protection using functions lock_ufs, unlock_ufs and struct mutex 'mutex'
in sb_info.

Commit b6963327 ("ufs: drop lock/unlock super") removed lock/unlock
super and added struct mutex 's_lock' in sb_info.

Those 2 mutexes are generally locked/unlocked at the same time except in
allocation (balloc, ialloc).

This patch merges the 2 mutexes and propagates first commit solution.
It also adds mutex destruction before kfree during ufs_fill_super
failure and ufs_put_super.

[akpm@linux-foundation.org: avoid ifdefs, return -EROFS not -EINVAL]
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: "Chen, Jet" <jet.chen@intel.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

As of commit 799fef06 ("powerpc: Use generic idle loop"), this
applies to arch_cpu_idle() instead of cpu_idle().
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

As of commit 8dc7c5ec ("cris: Use generic idle loop"), cris no
longer provides cpu_idle().

- On cris-v10, etrax_gpio_wake_up_check() is called from default_idle()
  instead of cpu_idle(),

- On cris-v32, etrax_gpio_wake_up_check() is not called from
  default_idle(), so remove this (copy-and-paste?) part.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

After all architectures were converted to the generic idle framework,
commit d190e819 ("idle: Remove GENERIC_IDLE_LOOP config switch")
removed the last caller of cpu_idle().  The forward declarations in
header files were forgotten.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Len field is already set to zero, but not the from field which is sent
as 0xfffffffffffffe00.  This makes no sense, and may cause confuse
server implementations doing sanity checks (qemu-nbd is an example.)
Signed-off-by: Hani Benhabiles <hani@linux.com>
Cc: Paul Clements <paul.clements@us.sios.com>
Cc: Paul Clements <Paul.Clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk is meant to be used with an associated log level.  There are some
instances of printk scattered around the mm code where the log level is
missing.  Add a log level and adhere to suggestions by
scripts/checkpatch.pl by moving to the pr_* macros.

Also add the typical pr_fmt definition so that print statements can be
easily traced back to the modules where they occur, correlated one with
another, etc.  This will require the removal of some (now redundant)
prefixes on a few print statements.
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This makes it more likely that patch submitters will CC API/ABI changes to
the linux-api list, and tools like get_maintainer.pl will do so
automatically.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Michael Kerrisk <mtk.man-pages@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-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>

Replace seq_printf where possible.  This patch also fixes the following
checkpatch warning "unnecessary whitespace before a quoted newline"
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Christine Caulfield <ccaulfie@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Replace obsolete functions.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Christine Caulfield <ccaulfie@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Replace obsolete functions

simple_strtoul/kstrtouint
simple_strtol/kstrtoint
(kstr __must_check requires the right function to be applied)
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Christine Caulfield <ccaulfie@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The remap_file_pages() system call is used to create a nonlinear
mapping, that is, a mapping in which the pages of the file are mapped
into a nonsequential order in memory.  The advantage of using
remap_file_pages() over using repeated calls to mmap(2) is that the
former approach does not require the kernel to create additional VMA
(Virtual Memory Area) data structures.

Supporting of nonlinear mapping requires significant amount of
non-trivial code in kernel virtual memory subsystem including hot paths.
Also to get nonlinear mapping work kernel need a way to distinguish
normal page table entries from entries with file offset (pte_file).
Kernel reserves flag in PTE for this purpose.  PTE flags are scarce
resource especially on some CPU architectures.  It would be nice to free
up the flag for other usage.

Fortunately, there are not many users of remap_file_pages() in the wild.
It's only known that one enterprise RDBMS implementation uses the
syscall on 32-bit systems to map files bigger than can linearly fit into
32-bit virtual address space.  This use-case is not critical anymore
since 64-bit systems are widely available.

The plan is to deprecate the syscall and replace it with an emulation.
The emulation will create new VMAs instead of nonlinear mappings.  It's
going to work slower for rare users of remap_file_pages() but ABI is
preserved.

One side effect of emulation (apart from performance) is that user can
hit vm.max_map_count limit more easily due to additional VMAs.  See
comment for DEFAULT_MAX_MAP_COUNT for more details on the limit.

[akpm@linux-foundation.org: fix spello]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Armin Rigo <arigo@tunes.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Jianyu Zhan <nasa4836@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Memcg zoneinfo lookup sites have either the page, the zone, or the node
id and zone index, but sites that only have the zone have to look up the
node id and zone index themselves, whereas sites that already have those
two integers use a function for a simple pointer chase.

Provide mem_cgroup_zone_zoneinfo() that takes a zone pointer and let
sites that already have node id and zone index - all for each node, for
each zone iterators - use &memcg->nodeinfo[nid]->zoneinfo[zid].

Rename page_cgroup_zoneinfo() to mem_cgroup_page_zoneinfo() to match.
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
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>

Kmemleak could ignore memory blocks allocated via memblock_alloc()
leading to false positives during scanning.  This patch adds the
corresponding callbacks and removes kmemleak_free_* calls in
mm/nobootmem.c to avoid duplication.

The kmemleak_alloc() in mm/nobootmem.c is kept since
__alloc_memory_core_early() does not use memblock_alloc() directly.
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>

When mempool_alloc() returns an existing pool object, kmemleak_alloc()
is no longer called and the stack trace corresponds to the original
object allocation.  This patch updates the kmemleak allocation stack
trace for such objects to make it more useful for debugging.
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>

Since radix_tree_preload() stack trace is not always useful for
debugging an actual radix tree memory leak, this patch updates the
kmemleak allocation stack trace in the radix_tree_node_alloc() function.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The memory allocation stack trace is not always useful for debugging a
memory leak (e.g.  radix_tree_preload).  This function, when called,
updates the stack trace for an already allocated object.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
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>

Memory reclaim always uses swappiness of the reclaim target memcg
(origin of the memory pressure) or vm_swappiness for global memory
reclaim.  This behavior was consistent (except for difference between
global and hard limit reclaim) because swappiness was enforced to be
consistent within each memcg hierarchy.

After "mm: memcontrol: remove hierarchy restrictions for swappiness and
oom_control" each memcg can have its own swappiness independent of
hierarchical parents, though, so the consistency guarantee is gone.
This can lead to an unexpected behavior.  Say that a group is explicitly
configured to not swapout by memory.swappiness=0 but its memory gets
swapped out anyway when the memory pressure comes from its parent with a
It is also unexpected that the knob is meaningless without setting the
hard limit which would trigger the reclaim and enforce the swappiness.
There are setups where the hard limit is configured higher in the
hierarchy by an administrator and children groups are under control of
somebody else who is interested in the swapout behavior but not
necessarily about the memory limit.

From a semantic point of view swappiness is an attribute defining anon
vs.
 file proportional scanning of LRU which is memcg specific (unlike
charges which are propagated up the hierarchy) so it should be applied
to the particular memcg's LRU regardless where the memory pressure comes
from.

This patch removes vmscan_swappiness() and stores the swappiness into
the scan_control structure.  mem_cgroup_swappiness is then used to
provide the correct value before shrink_lruvec is called.  The global
vm_swappiness is used for the root memcg.

[hughd@google.com: oopses immediately when booted with cgroup_disable=memory]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
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>

Some sysrq handlers can run for a long time, because they dump a lot of
data onto a serial console.  Having RCU stall warnings pop up in the
middle of them only makes the problem worse.

This patch temporarily disables RCU stall warnings while a sysrq request
is handled.
Signed-off-by: Rik van Riel <riel@redhat.com>
Suggested-by: Paul McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Madper Xie <cxie@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Echoing values into /proc/sysrq-trigger seems to be a popular way to get
information out of the kernel.  However, dumping information about
thousands of processes, or hundreds of CPUs to serial console can result
in IRQs being blocked for minutes, resulting in various kinds of cascade
failures.

The most common failure is due to interrupts being blocked for a very
long time.  This can lead to things like failed IO requests, and other
things the system cannot easily recover from.

This problem is easily fixable by making __handle_sysrq use RCU instead
of spin_lock_irqsave.

This leaves the warning that RCU grace periods have not elapsed for a
long time, but the system will come back from that automatically.

It also leaves sysrq-from-irq-context when the sysrq keys are pressed,
but that is probably desired since people want that to work in
situations where the system is already hosed.

The callers of register_sysrq_key and unregister_sysrq_key appear to be
capable of sleeping.
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Madper Xie <cxie@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

__constant_cpu_to_le32 converted to cpu_to_le32
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

-Trivial code clean-up
-Fix endif }; (coccinelle warning)
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Performing vma lookups without taking the mm->mmap_sem is asking for
trouble.  While doing the search, the vma in question can be modified or
even removed before returning to the caller.  Take the lock (shared) in
order to avoid races while iterating through the vmacache and/or rbtree.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: Steven Miao <realmz6@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This typedef is unnecessary and should just be removed.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>