page allocator: reduce fragmentation in buddy allocator by adding buddies that are merging to the tail of the free lists

In order to reduce fragmentation, this patch classifies freed pages in two
groups according to their probability of being part of a high order merge.
 Pages belonging to a compound whose next-highest buddy is free are more
likely to be part of a high order merge in the near future, so they will
be added at the tail of the freelist.  The remaining pages are put at the
front of the freelist.

In this way, the pages that are more likely to cause a big merge are kept
free longer.  Consequently there is a tendency to aggregate the
long-living allocations on a subset of the compounds, reducing the
fragmentation.

This heuristic was tested on three machines, x86, x86-64 and ppc64 with
3GB of RAM in each machine.  The tests were kernbench, netperf, sysbench
and STREAM for performance and a high-order stress test for huge page
allocations.

KernBench X86
Elapsed mean     374.77 ( 0.00%)   375.10 (-0.09%)
User    mean     649.53 ( 0.00%)   650.44 (-0.14%)
System  mean      54.75 ( 0.00%)    54.18 ( 1.05%)
CPU     mean     187.75 ( 0.00%)   187.25 ( 0.27%)

KernBench X86-64
Elapsed mean      94.45 ( 0.00%)    94.01 ( 0.47%)
User    mean     323.27 ( 0.00%)   322.66 ( 0.19%)
System  mean      36.71 ( 0.00%)    36.50 ( 0.57%)
CPU     mean     380.75 ( 0.00%)   381.75 (-0.26%)

KernBench PPC64
Elapsed mean     173.45 ( 0.00%)   173.74 (-0.17%)
User    mean     587.99 ( 0.00%)   587.95 ( 0.01%)
System  mean      60.60 ( 0.00%)    60.57 ( 0.05%)
CPU     mean     373.50 ( 0.00%)   372.75 ( 0.20%)

Nothing notable for kernbench.

NetPerf UDP X86
      64    42.68 ( 0.00%)     42.77 ( 0.21%)
     128    85.62 ( 0.00%)     85.32 (-0.35%)
     256   170.01 ( 0.00%)    168.76 (-0.74%)
    1024   655.68 ( 0.00%)    652.33 (-0.51%)
    2048  1262.39 ( 0.00%)   1248.61 (-1.10%)
    3312  1958.41 ( 0.00%)   1944.61 (-0.71%)
    4096  2345.63 ( 0.00%)   2318.83 (-1.16%)
    8192  4132.90 ( 0.00%)   4089.50 (-1.06%)
   16384  6770.88 ( 0.00%)   6642.05 (-1.94%)*

NetPerf UDP X86-64
      64   148.82 ( 0.00%)    154.92 ( 3.94%)
     128   298.96 ( 0.00%)    312.95 ( 4.47%)
     256   583.67 ( 0.00%)    626.39 ( 6.82%)
    1024  2293.18 ( 0.00%)   2371.10 ( 3.29%)
    2048  4274.16 ( 0.00%)   4396.83 ( 2.79%)
    3312  6356.94 ( 0.00%)   6571.35 ( 3.26%)
    4096  7422.68 ( 0.00%)   7635.42 ( 2.79%)*
    8192 12114.81 ( 0.00%)* 12346.88 ( 1.88%)
   16384 17022.28 ( 0.00%)* 17033.19 ( 0.06%)*
             1.64%             2.73%

NetPerf UDP PPC64
      64    49.98 ( 0.00%)     50.25 ( 0.54%)
     128    98.66 ( 0.00%)    100.95 ( 2.27%)
     256   197.33 ( 0.00%)    191.03 (-3.30%)
    1024   761.98 ( 0.00%)    785.07 ( 2.94%)
    2048  1493.50 ( 0.00%)   1510.85 ( 1.15%)
    3312  2303.95 ( 0.00%)   2271.72 (-1.42%)
    4096  2774.56 ( 0.00%)   2773.06 (-0.05%)
    8192  4918.31 ( 0.00%)   4793.59 (-2.60%)
   16384  7497.98 ( 0.00%)   7749.52 ( 3.25%)

The tests are run to have confidence limits within 1%.  Results marked
with a * were not confident although in this case, it's only outside by
small amounts.  Even with some results that were not confident, the
netperf UDP results were generally positive.

NetPerf TCP X86
      64   652.25 ( 0.00%)*   648.12 (-0.64%)*
            23.80%            22.82%
     128  1229.98 ( 0.00%)*  1220.56 (-0.77%)*
            21.03%            18.90%
     256  2105.88 ( 0.00%)   1872.03 (-12.49%)*
             1.00%            16.46%
    1024  3476.46 ( 0.00%)*  3548.28 ( 2.02%)*
            13.37%            11.39%
    2048  4023.44 ( 0.00%)*  4231.45 ( 4.92%)*
             9.76%            12.48%
    3312  4348.88 ( 0.00%)*  4396.96 ( 1.09%)*
             6.49%             8.75%
    4096  4726.56 ( 0.00%)*  4877.71 ( 3.10%)*
             9.85%             8.50%
    8192  4732.28 ( 0.00%)*  5777.77 (18.10%)*
             9.13%            13.04%
   16384  5543.05 ( 0.00%)*  5906.24 ( 6.15%)*
             7.73%             8.68%

NETPERF TCP X86-64
            netperf-tcp-vanilla-netperf       netperf-tcp
                   tcp-vanilla     pgalloc-delay
      64  1895.87 ( 0.00%)*  1775.07 (-6.81%)*
             5.79%             4.78%
     128  3571.03 ( 0.00%)*  3342.20 (-6.85%)*
             3.68%             6.06%
     256  5097.21 ( 0.00%)*  4859.43 (-4.89%)*
             3.02%             2.10%
    1024  8919.10 ( 0.00%)*  8892.49 (-0.30%)*
             5.89%             6.55%
    2048 10255.46 ( 0.00%)* 10449.39 ( 1.86%)*
             7.08%             7.44%
    3312 10839.90 ( 0.00%)* 10740.15 (-0.93%)*
             6.87%             7.33%
    4096 10814.84 ( 0.00%)* 10766.97 (-0.44%)*
             6.86%             8.18%
    8192 11606.89 ( 0.00%)* 11189.28 (-3.73%)*
             7.49%             5.55%
   16384 12554.88 ( 0.00%)* 12361.22 (-1.57%)*
             7.36%             6.49%

NETPERF TCP PPC64
            netperf-tcp-vanilla-netperf       netperf-tcp
                   tcp-vanilla     pgalloc-delay
      64   594.17 ( 0.00%)    596.04 ( 0.31%)*
             1.00%             2.29%
     128  1064.87 ( 0.00%)*  1074.77 ( 0.92%)*
             1.30%             1.40%
     256  1852.46 ( 0.00%)*  1856.95 ( 0.24%)
             1.25%             1.00%
    1024  3839.46 ( 0.00%)*  3813.05 (-0.69%)
             1.02%             1.00%
    2048  4885.04 ( 0.00%)*  4881.97 (-0.06%)*
             1.15%             1.04%
    3312  5506.90 ( 0.00%)   5459.72 (-0.86%)
    4096  6449.19 ( 0.00%)   6345.46 (-1.63%)
    8192  7501.17 ( 0.00%)   7508.79 ( 0.10%)
   16384  9618.65 ( 0.00%)   9490.10 (-1.35%)

There was a distinct lack of confidence in the X86* figures so I included
what the devation was where the results were not confident.  Many of the
results, whether gains or losses were within the standard deviation so no
solid conclusion can be reached on performance impact.  Looking at the
figures, only the X86-64 ones look suspicious with a few losses that were
outside the noise.  However, the results were so unstable that without
knowing why they vary so much, a solid conclusion cannot be reached.

SYSBENCH X86
              sysbench-vanilla     pgalloc-delay
           1  7722.85 ( 0.00%)  7756.79 ( 0.44%)
           2 14901.11 ( 0.00%) 13683.44 (-8.90%)
           3 15171.71 ( 0.00%) 14888.25 (-1.90%)
           4 14966.98 ( 0.00%) 15029.67 ( 0.42%)
           5 14370.47 ( 0.00%) 14865.00 ( 3.33%)
           6 14870.33 ( 0.00%) 14845.57 (-0.17%)
           7 14429.45 ( 0.00%) 14520.85 ( 0.63%)
           8 14354.35 ( 0.00%) 14362.31 ( 0.06%)

SYSBENCH X86-64
           1 17448.70 ( 0.00%) 17484.41 ( 0.20%)
           2 34276.39 ( 0.00%) 34251.00 (-0.07%)
           3 50805.25 ( 0.00%) 50854.80 ( 0.10%)
           4 66667.10 ( 0.00%) 66174.69 (-0.74%)
           5 66003.91 ( 0.00%) 65685.25 (-0.49%)
           6 64981.90 ( 0.00%) 65125.60 ( 0.22%)
           7 64933.16 ( 0.00%) 64379.23 (-0.86%)
           8 63353.30 ( 0.00%) 63281.22 (-0.11%)
           9 63511.84 ( 0.00%) 63570.37 ( 0.09%)
          10 62708.27 ( 0.00%) 63166.25 ( 0.73%)
          11 62092.81 ( 0.00%) 61787.75 (-0.49%)
          12 61330.11 ( 0.00%) 61036.34 (-0.48%)
          13 61438.37 ( 0.00%) 61994.47 ( 0.90%)
          14 62304.48 ( 0.00%) 62064.90 (-0.39%)
          15 63296.48 ( 0.00%) 62875.16 (-0.67%)
          16 63951.76 ( 0.00%) 63769.09 (-0.29%)

SYSBENCH PPC64
                             -sysbench-pgalloc-delay-sysbench
              sysbench-vanilla     pgalloc-delay
           1  7645.08 ( 0.00%)  7467.43 (-2.38%)
           2 14856.67 ( 0.00%) 14558.73 (-2.05%)
           3 21952.31 ( 0.00%) 21683.64 (-1.24%)
           4 27946.09 ( 0.00%) 28623.29 ( 2.37%)
           5 28045.11 ( 0.00%) 28143.69 ( 0.35%)
           6 27477.10 ( 0.00%) 27337.45 (-0.51%)
           7 26489.17 ( 0.00%) 26590.06 ( 0.38%)
           8 26642.91 ( 0.00%) 25274.33 (-5.41%)
           9 25137.27 ( 0.00%) 24810.06 (-1.32%)
          10 24451.99 ( 0.00%) 24275.85 (-0.73%)
          11 23262.20 ( 0.00%) 23674.88 ( 1.74%)
          12 24234.81 ( 0.00%) 23640.89 (-2.51%)
          13 24577.75 ( 0.00%) 24433.50 (-0.59%)
          14 25640.19 ( 0.00%) 25116.52 (-2.08%)
          15 26188.84 ( 0.00%) 26181.36 (-0.03%)
          16 26782.37 ( 0.00%) 26255.99 (-2.00%)

Again, there is little to conclude here.  While there are a few losses,
the results vary by +/- 8% in some cases.  They are the results of most
concern as there are some large losses but it's also within the variance
typically seen between kernel releases.

The STREAM results varied so little and are so verbose that I didn't
include them here.

The final test stressed how many huge pages can be allocated.  The
absolute number of huge pages allocated are the same with or without the
page.  However, the "unusability free space index" which is a measure of
external fragmentation was slightly lower (lower is better) throughout the
lifetime of the system.  I also measured the latency of how long it took
to successfully allocate a huge page.  The latency was slightly lower and
on X86 and PPC64, more huge pages were allocated almost immediately from
the free lists.  The improvement is slight but there.

[mel@csn.ul.ie: Tested, reworked for less branches]
[czoccolo@gmail.com: fix oops by checking pfn_valid_within()]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Shaohua Li reported parallel file copy on tmpfs can lead to OOM killer.
This is regression of caused by commit 9ff473b9 ("vmscan: evict
streaming IO first").  Wow, It is 2 years old patch!

Currently, tmpfs file cache is inserted active list at first.  This means
that the insertion doesn't only increase numbers of pages in anon LRU, but
it also reduces anon scanning ratio.  Therefore, vmscan will get totally
confused.  It scans almost only file LRU even though the system has plenty
unused tmpfs pages.

Historically, lru_cache_add_active_anon() was used for two reasons.
1) Intend to priotize shmem page rather than regular file cache.
2) Intend to avoid reclaim priority inversion of used once pages.

But we've lost both motivation because (1) Now we have separate anon and
file LRU list.  then, to insert active list doesn't help such priotize.
(2) In past, one pte access bit will cause page activation.  then to
insert inactive list with pte access bit mean higher priority than to
insert active list.  Its priority inversion may lead to uninteded lru
chun.  but it was already solved by commit 64574746 (vmscan: detect
mapped file pages used only once).  (Thanks Hannes, you are great!)

Thus, now we can use lru_cache_add_anon() instead.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: Shaohua Li <shaohua.li@intel.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fix the following 'make includecheck' warnings:

  arch/xtensa/kernel/vectors.S: asm/processor.h is included more than once.
  arch/xtensa/kernel/vectors.S: asm/ptrace.h is included more than once.
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Also remove lots of unused irq_cpustat fields.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Architectures that handle DMA-non-coherent memory need to set
ARCH_KMALLOC_MINALIGN to make sure that kmalloc'ed buffer is DMA-safe: the
buffer doesn't share a cache with the others.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-2.6:
  cmd640: fix kernel oops in test_irq() method
  pdc202xx_old: ignore "FIFO empty" bit in test_irq() method
  pdc202xx_old: wire test_irq() method for PDC2026x
  IDE: pass IRQ flags to the IDE core
  ide: fix comment typo in ide.h

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfin: (30 commits)
  Blackfin: SMP: fix continuation lines
  Blackfin: acvilon: fix timeout usage for I2C
  Blackfin: fix typo in BF537 IRQ comment
  Blackfin: unify duplicate MEM_MT48LC32M8A2_75 kconfig options
  Blackfin: set ARCH_KMALLOC_MINALIGN
  Blackfin: use atomic kmalloc in L1 alloc so it too can be atomic
  Blackfin: another year of changes (update copyright in boot log)
  Blackfin: optimize strncpy a bit
  Blackfin: isram: clean up ITEST_COMMAND macro and improve the selftests
  Blackfin: move string functions to normal lib/ assembly
  Blackfin: SIC: cut down on IAR MMR reads a bit
  Blackfin: bf537-minotaur: fix build errors due to header changes
  Blackfin: kgdb: pass up the CC register instead of a 0 stub
  Blackfin: handle HW errors in the new "FAULT" printing code
  Blackfin: show the whole accumulator in the pseudo DBG insn
  Blackfin: support all possible registers in the pseudo instructions
  Blackfin: add support for the DBG (debug output) pseudo insn
  Blackfin: change the BUG opcode to an unused 16-bit opcode
  Blackfin: allow NMI watchdog to be used w/RETN as a scratch reg
  Blackfin: add support for the DBGA (debug assert) pseudo insn
  ...

* 'bkl/ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing:
  uml: Pushdown the bkl from harddog_kern ioctl
  sunrpc: Pushdown the bkl from sunrpc cache ioctl
  sunrpc: Pushdown the bkl from ioctl
  autofs4: Pushdown the bkl from ioctl
  uml: Convert to unlocked_ioctls to remove implicit BKL
  ncpfs: BKL ioctl pushdown
  coda: Clean-up whitespace problems in pioctl.c
  coda: BKL ioctl pushdown
  drivers: Push down BKL into various drivers
  isdn: Push down BKL into ioctl functions
  scsi: Push down BKL into ioctl functions
  dvb: Push down BKL into ioctl functions
  smbfs: Push down BKL into ioctl function
  coda/psdev: Remove BKL from ioctl function
  um/mmapper: Remove BKL usage
  sn_hwperf: Kill BKL usage
  hfsplus: Push down BKL into ioctl function

* git://git.infradead.org/battery-2.6:
  ds2760_battery: Document ABI change
  ds2760_battery: Make charge_now and charge_full writeable
  power_supply: Add support for writeable properties
  power_supply: Use attribute groups
  power_supply: Add test_power driver
  tosa_battery: Fix build error due to direct driver_data usage
  wm97xx_battery: Quieten sparse warning (bat_set_pdata not declared)
  ds2782_battery: Get rid of magic numbers in driver_data
  ds2782_battery: Add support for ds2786 battery gas gauge
  pda_power: Add function callbacks for suspend and resume
  wm831x_power: Use genirq
  Driver for Zipit Z2 battery chip
  ds2782_battery: Fix clientdata on removal

Merge branch 'timers-for-linus-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'timers-for-linus-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  timers: Fix slack calculation for expired timers
  timekeeping: Fix timezone update

* git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: (25 commits)
  sh: fix up sh7785lcr_32bit_defconfig.
  arch/sh/lib/strlen.S: Checkpatch cleanup
  sh: fix up sh7786 dmaengine build.
  sh: guard cookie consistency across termination in the DMA driver
  sh: prevent the DMA driver from unloading, while in use
  sh: fix Oops in the serial SCI driver
  sh: allow platforms to specify SD-card supported voltages
  mmc: let MFD's provide supported Vdd card voltages to tmio_mmc
  sh: disable SD-card write-protection detection on kfr2r09
  mfd: pass platform flags down to the tmio_mmc driver
  tmio: add a platform flag to disable card write-protection detection
  sh: Add SDHI DMA support to migor
  sh: Add SDHI DMA support to kfr2r09
  sh: Add SDHI DMA support to ms7724se
  sh: Add SDHI DMA support to ecovec
  mmc: add DMA support to tmio_mmc driver, when used on SuperH
  sh: prepare the SDHI MFD driver to pass DMA configuration to tmio_mmc.c
  mmc: prepare tmio_mmc for passing of DMA configuration from the MFD cell
  sh: add DMA slave definitions to sh7724
  sh: add DMA slaves for two SDHI controllers to sh7722
  ...

* 'for-linus' of git://git.open-osd.org/linux-open-osd:
  exofs: confusion between kmap() and kmap_atomic() api
  exofs: Add default address_space_operations

This reverts commit 03ceedea, since it
breaks resume from suspend-to-ram on Rafael's Acer Ferrari One.
NetworkManager thinks everything is ok, but it can't connect to the AP
to get an IP address after the resume.

In fact, it even breaks resume for non-ath9k chipsets: reverting it also
fixes Rafael's Toshiba Protege R500 with the iwlagn driver.  As Johannes
says:

  "Indeed, this patch needs to be reverted. That mac80211 change is wrong
   and completely unnecessary."
Reported-and-requested-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Daniel Yingqiang Ma <yma.cool@gmail.com>
Cc: John W. Linville <linville@tuxdriver.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/hirofumi/fatfs-2.6:
  fat: convert to unlocked_ioctl
  fat: Cleanup nls_unload() usage
  fat: use pack_hex_byte() instead of custom one

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  9p: Optimize TCREATE by eliminating a redundant fid clone.
  9p: cleanup: remove unneeded assignment
  9p: Add mksock support
  fs/9p: Make sure we properly instantiate dentry.
  9p: add 9P2000.L rename operation
  9p: add 9P2000.L statfs operation
  9p: VFS switches for 9p2000.L: VFS switches
  9p: VFS switches for 9p2000.L: protocol and client changes

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (59 commits)
  ceph: reuse mon subscribe message instead of allocated anew
  ceph: avoid resending queued message to monitor
  ceph: Storage class should be before const qualifier
  ceph: all allocation functions should get gfp_mask
  ceph: specify max_bytes on readdir replies
  ceph: cleanup pool op strings
  ceph: Use kzalloc
  ceph: use common helper for aborted dir request invalidation
  ceph: cope with out of order (unsafe after safe) mds reply
  ceph: save peer feature bits in connection structure
  ceph: resync headers with userland
  ceph: use ceph. prefix for virtual xattrs
  ceph: throw out dirty caps metadata, data on session teardown
  ceph: attempt mds reconnect if mds closes our session
  ceph: clean up send_mds_reconnect interface
  ceph: wait for mds OPEN reply to indicate reconnect success
  ceph: only send cap releases when mds is OPEN|HUNG
  ceph: dicard cap releases on mds restart
  ceph: make mon client statfs handling more generic
  ceph: drop src address(es) from message header [new protocol feature]
  ...

* 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6:
  of: change of_match_device to work with struct device
  of: Remove duplicate fields from of_platform_driver
  drivercore: Add of_match_table to the common device drivers
  arch/microblaze: Move dma_mask from of_device into pdev_archdata
  arch/powerpc: Move dma_mask from of_device into pdev_archdata
  of: eliminate of_device->node and dev_archdata->{of,prom}_node
  of: Always use 'struct device.of_node' to get device node pointer.
  i2c/of: Allow device node to be passed via i2c_board_info
  driver-core: Add device node pointer to struct device
  of: protect contents of of_platform.h and of_device.h
  of/flattree: Make unflatten_device_tree() safe to call from any arch
  of/flattree: make of_fdt.h safe to unconditionally include.

* 'slab-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  slub: Use alloc_pages_exact_node() for page allocation
  slub: __kmalloc_node_track_caller should trace kmalloc_large_node case
  slub: Potential stack overflow
  crypto: Use ARCH_KMALLOC_MINALIGN for CRYPTO_MINALIGN now that it's exposed
  mm: Move ARCH_SLAB_MINALIGN and ARCH_KMALLOC_MINALIGN to <linux/slub_def.h>
  mm: Move ARCH_SLAB_MINALIGN and ARCH_KMALLOC_MINALIGN to <linux/slob_def.h>
  mm: Move ARCH_SLAB_MINALIGN and ARCH_KMALLOC_MINALIGN to <linux/slab_def.h>
  slab: Fix missing DEBUG_SLAB last user
  slab: add memory hotplug support
  slab: Fix continuation lines

Add build testing using 'O=builddir'.

Add build testing with various kconfig symbols disabled, listing
common ones that are known to cause build problems.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The function name must be followed by a space, hypen, space, and a
short description.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scsi_scan.c: fix incorrectly formatted kernel-doc notation
& convert documentation of 2 functions into kernel-doc.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

documentation: slightly more correct value for MAP_HUGETLB in map_hugetlb.c

still not correct for alpha, mips, parisc or xtensa but working out of
the box in the most common architectures without having to deal with
complicated macros or including architecture specific headers.
Signed-off-by: Carlo Marcelo Arenas Belon <carenas@sajinet.com.pe>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/timers/hpet_example.c: fcntl.h is included more than once.
Documentation/timers/hpet_example.c: signal.h is included more than once.
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Update explanation of mmotm.
Add explanation of drivers/staging/.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add info on maintainers and persistent posting.
Update git home page.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In the example the module_init function should be static.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

commit 3bbb9ec9 (timers: Introduce the concept of timer slack for
legacy timers) does not take the case into account when the timer is
already expired. This broke wireless drivers.

The solution is not to apply slack to already expired timers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>

commit 64ce4c2f (time: Clean up warp_clock()) breaks the timezone
update in a very subtle way. To avoid the direct access to timekeeping
internals it adds the timezone delta to the current time with
timespec_add_safe(). This works nicely when the timezone delta is > 0.
If timezone delta is < 0 then the wrap check in timespec_add_safe()
triggers and timespec_add_safe() returns TIME_MAX and screws up
timekeeping completely. 

The comment above timespec_add_safe() says:
    It's assumed that both values are valid (>= 0)

Add the timezone seconds adjustment directly.
Reported-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

The build scripts inadvertently dropped this down to 29-bit, fix it
back up.
Reported-by: Raul Porcel <armin76@gentoo.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/lib/strlen.S:38: ERROR: trailing whitespace
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

The timeout value is in jiffies, so it should be using HZ, not a plain
number. As '10000' is ambiguous, 1HZ is used as conservative default.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Valentin Yakovenkov <yakovenkov@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Reported-by: Christoph Egger <siccegge@cs.fau.de>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Architectures that handle DMA-non-coherent memory need to set
ARCH_KMALLOC_MINALIGN to make sure that kmalloc'ed buffer is DMA-safe:
the buffer doesn't share a cache with the others.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Some drivers allocate L1 SRAM in atomic contexts, so make sure these
functions also use GFP_ATOMIC to avoid BUG()'s.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Add a little strncpy optimization which can easily cut boot time by 20%.

When the kernel is booting with initramfs, it builds up the filesystem
from a cpio archive by calling strncpy_from_user() via fs/namei.c's
do_getname() on every file in the archive (which can be lots) with a
length of PATH_MAX (1024).  This causes the dest of the strncpy to be
padded with many NUL bytes.

This optimization mostly causes these NUL bytes to be padded with a call
to memset() which is already optimized for filling memory quickly, but
the hardware loop helps a little bit as well.

Boot time measured with 'loglevel=0' so UART speed doesn't get in the way.
Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

The IADDR2DTEST() macro had some duplicated logic with bit 11 and some
incorrect comments, so scrub all of that.

In order to verify these aren't a problem (and won't be in the future),
extend the self tests to operate on as much L1 SRAM as possible.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Since 'extern inline' doesn't work correctly in the context of the Linux
kernel (too many overriding defines), move the string functions to normal
lib/ assembly files (like the existing mem funcs).  This avoids the forced
inline all over the kernel and allows us to place them constantly in L1.

This also avoids some module failures when gcc inserts calls to string
functions but the kernel build system doesn't fully consult the library
archives.
Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>