vmscan: fix initial shrinker size handling

A shrinker function can return -1, means that it cannot do anything
without a risk of deadlock.  For example prune_super() does this if it
cannot grab a superblock refrence, even if nr_to_scan=0.  Currently we
interpret this -1 as a ULONG_MAX size shrinker and evaluate `total_scan'
according to this.  So the next time around this shrinker can cause really
big pressure.  Let's skip such shrinkers instead.

Also make total_scan signed, otherwise the check (total_scan < 0) below
never works.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Merge remote-tracking branch 'kvmtool/master'

Conflicts:
include/net/9p/9p.h
scripts/kconfig/Makefile

Merge remote-tracking branch 'kmap_atomic/kmap_atomic'

Merge remote-tracking branch 'vhost/linux-next'

Conflicts:
arch/hexagon/Kconfig
arch/m68k/Kconfig

Merge remote-tracking branch 'pinctrl/for-next'

Merge remote-tracking branch 'writeback/writeback-for-next'

Merge remote-tracking branch 'tmem/tmem'

Conflicts:
mm/swapfile.c

Merge remote-tracking branch 'char-misc/char-misc-next'

Merge remote-tracking branch 'staging/staging-next'

Conflicts:
drivers/hid/hid-hyperv.c
drivers/staging/hv/Kconfig
drivers/staging/hv/Makefile
drivers/staging/iio/adc/ad799x_core.c
drivers/staging/iio/industrialio-core.c

Merge remote-tracking branch 'usb/usb-next'

Merge remote-tracking branch 'tty/tty-next'

Conflicts:
drivers/tty/serial/Kconfig
drivers/tty/serial/Makefile

Merge remote-tracking branch 'driver-core/driver-core-next'

Merge remote-tracking branch 'hsi/for-next'

Merge remote-tracking branch 'regmap/for-next'

Merge remote-tracking branch 'namespace/master'

Merge remote-tracking branch 'sysctl/master'

Merge remote-tracking branch 'xen-two/linux-next'

Conflicts:
arch/x86/xen/Kconfig

Merge remote-tracking branch 'xen/upstream/xen'

Conflicts:
arch/x86/xen/Kconfig

Merge remote-tracking branch 'kmemleak/kmemleak'

Merge remote-tracking branch 'uprobes/for-next'

Merge remote-tracking branch 'tip/auto-latest'

Conflicts:
arch/mips/kernel/perf_event_mipsxx.c

Merge remote-tracking branch 'edac-amd/for-next'

Merge remote-tracking branch 'fsnotify/for-next'

Merge remote-tracking branch 'apm/for-next'

Merge remote-tracking branch 'pm/linux-next'

Merge remote-tracking branch 'trivial/for-next'

Conflicts:
arch/powerpc/platforms/40x/Kconfig
net/mac80211/work.c

Merge remote-tracking branch 'osd/linux-next'

Merge remote-tracking branch 'cputime/cputime'

Merge remote-tracking branch 'iommu/next'

Merge remote-tracking branch 'watchdog/linux-next'

Merge remote-tracking branch 'security/next'

Conflicts:
lib/Makefile

Merge remote-tracking branch 'regulator/for-next'

Merge remote-tracking branch 'fbdev/fbdev-next'

Merge remote-tracking branch 'drm/drm-next'

Merge remote-tracking branch 'md/for-next'

Merge remote-tracking branch 'slab/for-next'

Merge remote-tracking branch 'kgdb/kgdb-next'

Merge remote-tracking branch 'mmc/mmc-next'

Merge remote-tracking branch 'battery/master'

Merge remote-tracking branch 'block/for-next'

Merge remote-tracking branch 'input/next'

Conflicts:
drivers/input/keyboard/samsung-keypad.c

Merge branch 'quilt/rr'

Merge remote-tracking branch 'cpufreq/next'

Merge remote-tracking branch 'sound-asoc/for-next'

Conflicts:
arch/arm/mach-s3c64xx/mach-crag6410.c

Merge remote-tracking branch 'sound/for-next'

Merge remote-tracking branch 'crypto/master'

Merge remote-tracking branch 'l2-mtd/master'

Merge remote-tracking branch 'mtd/master'

Merge remote-tracking branch 'bluetooth/master'

Merge remote-tracking branch 'wireless-next/master'

Conflicts:
drivers/net/wireless/iwlwifi/iwl-agn.c

Merge remote-tracking branch 'net-next/master'

Conflicts:
drivers/net/wireless/iwlwifi/iwl-agn.c

Merge remote-tracking branch 'slave-dma/next'

Conflicts:
drivers/dma/pl330.c

Merge remote-tracking branch 'target-merge/for-next-merge'

Merge remote-tracking branch 'dlm/next'

Merge remote-tracking branch 'ubi/linux-next'

Merge remote-tracking branch 'libata/NEXT'

Merge remote-tracking branch 'kconfig/for-next'

Merge remote-tracking branch 'kbuild/for-next'

Merge remote-tracking branch 'v4l-dvb/master'

Conflicts:
drivers/staging/media/as102/as102_drv.h

Merge remote-tracking branch 'hwmon-staging/hwmon-next'

Merge branch 'quilt/jdelvare-hwmon'

Merge remote-tracking branch 'bjdooks-i2c/next-i2c'

Conflicts:
drivers/i2c/busses/i2c-designware-platdrv.c

Merge remote-tracking branch 'hid/for-next'

Merge remote-tracking branch 'pci/linux-next'

Merge remote-tracking branch 'xfs/master'

Merge remote-tracking branch 'ubifs/linux-next'

Merge remote-tracking branch 'nfsd/nfsd-next'

Merge remote-tracking branch 'nfs/linux-next'

Merge remote-tracking branch 'logfs/master'

Conflicts:
fs/logfs/file.c

Merge remote-tracking branch 'gfs2/master'

Merge remote-tracking branch 'ecryptfs/next'

Merge remote-tracking branch 'cifs/master'

Merge remote-tracking branch 'xtensa/master'

Merge remote-tracking branch 'tile/master'

Merge remote-tracking branch 's390/features'

Merge remote-tracking branch '52xx-and-virtex/powerpc/next'

Merge remote-tracking branch '4xx/next'

Merge remote-tracking branch 'powerpc/next'

Merge remote-tracking branch 'parisc/for-next'

Merge remote-tracking branch 'mips/mips-for-linux-next'

Merge remote-tracking branch 'm68knommu/for-next'

Conflicts:
arch/m68k/Kconfig.debug

Merge remote-tracking branch 'm68k/for-next'

Merge remote-tracking branch 'ia64/next'

Merge branch 'quilt/hexagon'

Merge remote-tracking branch 'cris/for-next'

Merge remote-tracking branch 'c6x/for-linux-next'

Merge remote-tracking branch 'tegra/for-next'

Merge remote-tracking branch 's5p/for-next'

Conflicts:
arch/arm/mach-exynos/cpu.c
arch/arm/mach-exynos/include/mach/entry-macro.S
arch/arm/mach-s3c64xx/mach-crag6410.c

Merge remote-tracking branch 'i.MX/for-next'

Conflicts:
arch/arm/mach-imx/clock-mx51-mx53.c
arch/arm/mach-imx/devices-imx53.h
arch/arm/mach-imx/mm-imx5.c
arch/arm/mach-mx5/Kconfig
arch/arm/mach-mx5/Makefile
arch/arm/mach-mx5/pm-imx5.c
arch/arm/plat-mxc/include/mach/hardware.h

Merge remote-tracking branch 'arm-perf/for-next/perf'

Merge remote-tracking branch 'arm-soc/for-next'

Conflicts:
arch/arm/mach-at91/at91cap9.c
arch/arm/mach-at91/at91sam9260.c
arch/arm/mach-at91/at91sam9261.c
arch/arm/mach-at91/at91sam9263.c
arch/arm/mach-at91/at91sam9g45.c
arch/arm/mach-at91/at91sam9rl.c
arch/arm/mach-at91/setup.c

Merge remote-tracking branch 'arm-lpae/for-next'

Conflicts:
arch/arm/include/asm/pgalloc.h
arch/arm/include/asm/pgtable.h
arch/arm/include/asm/tlb.h
arch/arm/mm/ioremap.c

Merge remote-tracking branch 'arm/for-next'

Conflicts:
arch/arm/plat-omap/include/plat/common.h
arch/arm/tools/mach-types

Merge remote-tracking branch 'wireless/master'

Merge remote-tracking branch 'net/master'

Merge remote-tracking branch 'sparc/master'

lguest: switch segment-voodoo-numbers to readable symbols

When studying lguest's x86 segment descriptor code, it is not longer
necessary to have the Intel x86 architecture manual open on the page
with the segment descriptor illustration to understand the crazy
numbers assigned to both descriptor structure halves a/b.
Now the struct desc_struct's fields, like suggested by
Glauber de Oliveira Costa in 2008, are used.

Signed-off-by: Jacek Galowicz <jacek@galowicz.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

module: Fix performance regression on modules with large symbol tables

Looking at /proc/kallsyms, one starts to ponder whether all of the extra
strtab-related complexity in module.c is worth the memory savings.

Instead of making the add_kallsyms() loop even more complex, I tried the
other route of deleting the strmap logic and naively copying each string
into core_strtab with no consideration for consolidating duplicates.

Performance on an "already exists" insmod of nvidia.ko (runs
add_kallsyms() but does not actually initialize the module):

Original scheme: 1.230s
With naive copying: 0.058s

Extra space used: 35k (of a 408k module).

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <73defb5e4bca04a6431392cc341112b1@localhost>

module: Add comments describing how the "strmap" logic works

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio: add debugging if driver doesn't kick.

Under the existing #ifdef DEBUG, check that they don't have more than
1/10 of a second between an add_buf() and a
virtqueue_notify()/virtqueue_kick_prepare() call.

We could get false positives on a really busy system, but good for
development.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>