memcg: add mem_cgroup_replace_page_cache() to fix LRU issue

Commit ef6a3c6311 ("mm: add replace_page_cache_page() function") added a
function replace_page_cache_page().  This function replaces a page in the
radix-tree with a new page.  WHen doing this, memory cgroup needs to fix
up the accounting information.  memcg need to check PCG_USED bit etc.

In some(many?) cases, 'newpage' is on LRU before calling
replace_page_cache().  So, memcg's LRU accounting information should be
fixed, too.

This patch adds mem_cgroup_replace_page_cache() and removes the old hooks.
 In that function, old pages will be unaccounted without touching
res_counter and new page will be accounted to the memcg (of old page).
WHen overwriting pc->mem_cgroup of newpage, take zone->lru_lock and avoid
races with LRU handling.

Background:
  replace_page_cache_page() is called by FUSE code in its splice() handling.
  Here, 'newpage' is replacing oldpage but this newpage is not a newly allocated
  page and may be on LRU. LRU mis-accounting will be critical for memory cgroup
  because rmdir() checks the whole LRU is empty and there is no account leak.
  If a page is on the other LRU than it should be, rmdir() will fail.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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

Merge remote-tracking branch 'kvmtool/master'

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

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

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

Merge remote-tracking branch 'kmap_atomic/kmap_atomic'

Conflicts:
Documentation/feature-removal-schedule.txt

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

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

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'

Conflicts:
drivers/base/regmap/regcache.c
drivers/base/regmap/regmap.c

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 'oprofile/for-next'

Merge remote-tracking branch 'kmemleak/kmemleak'

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

Conflicts:
block/blk-cgroup.c

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

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

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

Conflicts:
arch/arm/mm/init.c
arch/powerpc/include/asm/cputime.h

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

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'

Conflicts:
fs/xfs/xfs_buf.c

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

Conflicts:
arch/powerpc/platforms/40x/Kconfig

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

Merge remote-tracking branch 'iommu/next'

Conflicts:
drivers/pci/hotplug/acpiphp_glue.c
include/linux/pci_regs.h

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'

Conflicts:
drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

Merge remote-tracking branch 'mfd/for-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'

Conflicts:
drivers/mmc/card/block.c

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 commit 'refs/next/20111219/rr'

Merge remote-tracking branch 'cpufreq/next'

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

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

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

Merge remote-tracking branch 'crypto/master'

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

Conflicts:
drivers/mtd/maps/bcm963xx-flash.c

Merge remote-tracking branch 'mtd/master'

Merge commit 'refs/next/20111220/bluetooth'

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

Conflicts:
net/bluetooth/l2cap_core.c

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

Conflicts:
drivers/dma/Kconfig
drivers/dma/pl330.c

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

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

Merge remote-tracking branch 'scsi/master'

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'

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 branch 'quilt/i2c'

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 'logfs/master'

Conflicts:
fs/logfs/file.c

Merge remote-tracking branch 'gfs2/master'

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

Merge remote-tracking branch 'ext4/dev'

Merge remote-tracking branch 'ecryptfs/next'

Merge remote-tracking branch 'xtensa/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'

Conflicts:
arch/mips/kernel/perf_event_mipsxx.c

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 'blackfin/for-linus'

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

Conflicts:
arch/arm/mach-tegra/board-dt-tegra20.c
arch/arm/mach-tegra/common.c

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

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

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

Conflicts:
arch/arm/mach-imx/clock-imx35.c
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-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-imx/mach-imx6q.c
arch/arm/mach-mxs/include/mach/common.h
arch/arm/mach-omap2/board-ti8168evm.c

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

Conflicts:
arch/arm/mach-mxs/mach-m28evk.c
arch/arm/mach-mxs/mach-stmp378x_devb.c
arch/arm/mach-shmobile/board-kota2.c