linux/Documentation
Konstantin Khlebnikov 77bb499bb6 pagemap: add mmap-exclusive bit for marking pages mapped only here
This patch sets bit 56 in pagemap if this page is mapped only once.  It
allows to detect exclusively used pages without exposing PFN:

present file exclusive state
0       0    0         non-present
1       1    0         file page mapped somewhere else
1       1    1         file page mapped only here
1       0    0         anon non-CoWed page (shared with parent/child)
1       0    1         anon CoWed page (or never forked)

CoWed pages in (MAP_FILE | MAP_PRIVATE) areas are anon in this context.

MMap-exclusive bit doesn't reflect potential page-sharing via swapcache:
page could be mapped once but has several swap-ptes which point to it.
Application could detect that by swap bit in pagemap entry and touch that
pte via /proc/pid/mem to get real information.

See http://lkml.kernel.org/r/CAEVpBa+_RyACkhODZrRvQLs80iy0sqpdrd0AaP_-tgnX3Y9yNQ@mail.gmail.com

Requested by Mark Williamson.

[akpm@linux-foundation.org: fix spello]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Mark Williamson <mwilliamson@undo-software.com>
Tested-by:  Mark Williamson <mwilliamson@undo-software.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>
2015-09-08 15:35:28 -07:00
..
ABI This is the bulk of GPIO changes for the v4.3 kernel cycle: 2015-09-04 10:07:45 -07:00
accounting Documentation: use subdir-y to avoid unnecessary built-in.o files 2014-09-26 11:02:55 +02:00
acpi ACPI / Documentation: Update method tracing documentation. 2015-08-07 02:42:22 +02:00
aoe
arm ARM: SoC platform updates for v4.3 2015-09-01 12:18:40 -07:00
arm64 arm64/Documentation: clarify wording regarding memory below the Image 2015-07-29 18:32:10 +01:00
auxdisplay Documentation: use subdir-y to avoid unnecessary built-in.o files 2014-09-26 11:02:55 +02:00
backlight
blackfin Docs: blackfin: Use new switch macro SAMPLE_IRQ_TIMER instead of IRQ_TIMER5 2015-05-07 09:35:14 -06:00
block Documentation: update notes in biovecs about arbitrarily sized bios 2015-08-13 12:32:07 -06:00
blockdev zram: add dynamic device add/remove functionality 2015-06-25 17:00:36 -07:00
bus-devices
cdrom
cgroups Merge branch 'for-4.3-unified-base' into for-4.3 2015-08-25 14:19:29 -04:00
cma cma: debug: document new debugfs interface 2015-04-14 16:49:00 -07:00
connector
console
cpu-freq cpufreq: remove redundant CPUFREQ_INCOMPATIBLE notifier event 2015-09-01 15:50:38 +02:00
cpuidle
cris
crypto crypto: doc - AEAD / RNG AF_ALG interface 2015-03-09 21:06:18 +11:00
development-process Documentation: remove outdated references to the linux-next wiki 2014-10-28 09:06:11 -04:00
device-mapper dm raid: document RAID 4/5/6 discard support 2015-08-31 15:05:31 -04:00
devicetree media updates for v4.3-rc1 2015-09-05 18:21:14 -07:00
dmaengine Documentation: dmaengine: Add DMA_CTRL_REUSE documentation 2015-08-17 13:46:22 +05:30
DocBook media updates for v4.3-rc1 2015-09-05 18:21:14 -07:00
driver-model Char/Misc driver patches for 4.1-rc1 2015-04-21 09:42:58 -07:00
dvb [media] get_dvb_firmware: Update firmware of ITEtech IT9135 2014-09-21 17:03:04 -03:00
early-userspace
EDID
extcon
fault-injection futex: Fault/error injection capabilities 2015-07-20 11:45:45 +02:00
fb Documentation/fb: add documentation for sm712fb 2015-08-07 15:05:01 -07:00
features Documentation/features/vm: add feature description and arch support status for batched TLB flush after unmap 2015-09-04 16:54:41 -07:00
filesystems dax: add huge page fault support 2015-09-08 15:35:28 -07:00
firmware_class
fmc
frv
gpio Documentation: gpio: consumer: describe active low property 2015-08-17 10:38:52 +02:00
hid HID: sensor: Update document for custom sensor 2015-04-10 22:22:56 +02:00
hwmon hwmon: (fam15h_power) Add documentation for new processors support 2015-08-27 07:51:15 -07:00
i2c Merge branch 'i2c/for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2015-06-25 18:42:39 -07:00
ia64 virtual: Documentation: simplify and generalize paravirt_ops.txt 2015-02-13 17:15:44 +10:30
ide
infiniband
input Merge branch 'next' into for-linus 2015-09-03 10:01:44 -07:00
ioctl userfaultfd: uAPI 2015-09-04 16:54:41 -07:00
isdn
ja_JP Doc: ja_JP: Fix typo in HOWTO 2015-06-08 16:43:09 -06:00
kbuild kbuild: Allow arch Makefiles to override {cpp,ld,c}flags 2015-07-06 11:09:00 +05:30
kdump kernel: add panic_on_warn 2014-12-10 17:41:10 -08:00
ko_KR
laptops Move freefall program from Documentation/ to tools/ 2015-06-08 16:42:07 -06:00
leds Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds 2015-07-01 19:09:11 -07:00
locking Documentation changes for 3.20 2015-02-11 13:03:11 -08:00
m68k
memory-devices
metag
mic Char/Misc driver patches for 4.2-rc1 2015-06-26 14:51:15 -07:00
mips
misc-devices mei: add async event notification ioctls 2015-08-03 17:30:00 -07:00
mmc
mn10300
mtd
namespaces
netlabel
networking Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-09-03 08:08:17 -07:00
nfc NFC: Fix typo in nfc-hci.txt 2015-06-08 23:15:45 +02:00
nios2 Documentation: Add documentation for Nios2 architecture 2014-12-08 12:56:06 +08:00
nvdimm libnvdimm: Non-Volatile Devices 2015-06-26 11:23:38 -04:00
nvmem Documentation: nvmem: add nvmem api level and how-to doc 2015-08-05 13:43:45 -07:00
parisc
PCI The documentation tree update for 4.1. Numerous fixes, the overdue removal 2015-04-18 11:10:49 -04:00
pcmcia pcmcia: Fix typo in locking documentation 2015-08-07 14:34:58 +02:00
phy
platform
power Power management and ACPI material for v4.3-rc1 2015-09-01 19:45:46 -07:00
powerpc SCSI misc on 20150901 2015-09-02 12:22:54 -07:00
pps Doc: pps: Fix file name in pps.txt 2015-07-14 12:35:42 -06:00
prctl Documentation/prctl: don't build tsc tests when cross compiling 2015-06-22 16:05:04 -06:00
pti
ptp ptp: restore the makefile for building the test program. 2014-10-24 16:07:10 -04:00
rapidio
RCU Merge branches 'doc.2015.07.15a' and 'torture.2015.07.15a' into HEAD 2015-08-04 08:42:02 -07:00
s390 KVM: s390: remove outdated documentation 2015-07-29 11:02:35 +02:00
scheduler sched/dl/Documentation: Split Section 3 2015-05-19 08:39:21 +02:00
scsi Merge branch 'for-4.2/sg' of git://git.kernel.dk/linux-block 2015-06-25 15:22:36 -07:00
security Smack: allow multiple labels in onlycap 2015-06-02 11:53:42 -07:00
serial Doc: serial-rs485.txt: update RS485 driver interface 2015-06-12 17:39:51 -07:00
sh
sound Doc: sound:oss: Fix typo in sound/oss 2015-06-09 17:23:00 +02:00
spi Documentation/spi/spidev_test.c: fix warning 2015-04-17 09:04:12 -04:00
sysctl Documentation: mm: fix location of extfrag_index 2015-07-24 15:05:56 +02:00
target Documentation/target: Fix tcm_mod_builder.py build breakage 2015-07-24 17:48:55 -07:00
thermal thermal: support slope and offset coefficients 2015-05-11 19:46:52 -07:00
timers documentation: Update NO_HZ_FULL interaction with POSIX timers 2015-02-26 11:57:29 -08:00
tpm
trace powerpc updates for 4.3 2015-09-03 16:41:38 -07:00
usb Revert "usb: interface authorization: Documentation part" 2015-08-18 09:57:15 -07:00
vDSO Documentation/vDSO: don't build tests when cross compiling 2015-06-22 16:04:57 -06:00
video4linux [media] Documentation: update cardlists 2015-06-09 18:43:47 -03:00
virtual kvm/x86: add sending hyper-v crash notification to user space 2015-07-23 08:27:06 +02:00
vm pagemap: add mmap-exclusive bit for marking pages mapped only here 2015-09-08 15:35:28 -07:00
w1 w1: Add support for DS28EA00 sequence to w1-therm 2015-05-24 12:08:59 -07:00
watchdog watchdog: omap_wdt: early_enable module parameter 2015-07-01 16:43:17 +02:00
wimax
x86 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 10:07:40 -07:00
xtensa
zh_CN Documentation updates for 4.2 2015-06-24 20:01:36 -07:00
00-INDEX Update of Documentation/dmaengine/00-INDEX 2014-12-29 15:28:24 -07:00
adding-syscalls.txt Documentation: describe how to add a system call 2015-08-13 17:54:06 -06:00
applying-patches.txt Documentation: change "&" to "and" in Documentation/applying-patches.txt 2014-09-26 11:10:11 +02:00
assoc_array.txt
atomic_ops.txt locking/Documentation: Clarify failed cmpxchg() memory ordering semantics 2015-08-03 10:57:09 +02:00
bad_memory.txt
basic_profiling.txt
bcache.txt
binfmt_misc.txt binfmt_misc: touch up documentation a bit 2014-10-14 02:18:16 +02:00
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt rmap: drop support of non-linear mappings 2015-02-10 14:30:31 -08:00
Changes Documentation: GNU is frequently spelled Gnu 2014-12-29 15:33:17 -07:00
circular-buffers.txt
clk.txt clk: change clk_ops' ->determine_rate() prototype 2015-07-27 18:12:01 -07:00
coccinelle.txt
CodeOfConflict Code of Conflict 2015-02-27 11:44:24 -08:00
CodingStyle Documentation: CodingStyle: remove broken links in the References section 2015-07-10 13:54:34 -06:00
cpu-hotplug.txt cpumask: fix cpu-hotplug documentation 2015-03-05 13:37:01 +10:30
cpu-load.txt
cputopology.txt Documentation: Update cputopology.txt 2015-05-27 15:22:15 +02:00
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt Doc: Change wikipedia's URL from http to https 2015-06-22 10:14:05 -06:00
dell_rbu.txt
devices.txt
digsig.txt
DMA-API-HOWTO.txt Documentation updates for 4.2 2015-06-24 20:01:36 -07:00
DMA-API.txt PCI: Add pci_bus_addr_t 2015-05-29 17:21:45 -05:00
DMA-attributes.txt
dma-buf-sharing.txt dma-buf: cleanup dma_buf_export() to make it easily extensible 2015-04-21 14:47:16 +05:30
DMA-ISA-LPC.txt
dontdiff
dynamic-debug-howto.txt
edac.txt EDAC: Update Documentation/edac.txt 2015-06-24 18:17:40 +02:00
efi-stub.txt
eisa.txt
email-clients.txt fix Evolution submenu name in email-clients.txt 2015-07-24 15:05:57 +02:00
flexible-arrays.txt
futex-requeue-pi.txt doc: Fix misnamed FUTEX_CMP_REQUEUE_PI op constants 2015-01-19 12:05:32 +01:00
gcov.txt
gdb-kernel-debugging.txt scripts/gdb: add basic documentation 2015-02-17 14:34:54 -08:00
highuid.txt
HOWTO docs: update HOWTO for 3.x -> 4.x versioning 2015-08-24 11:28:17 -06:00
hsi.txt
hw_random.txt
hwspinlock.txt hwspinlock/core: add device tree support 2015-05-02 09:54:30 +03:00
init.txt
initrd.txt
intel_txt.txt
Intel-IOMMU.txt Documentation/Intel-IOMMU.txt: Modify definition of DRHD 2015-08-24 11:39:45 -06:00
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt ipmi:ssif: Ignore spaces when comparing I2C adapter names 2015-05-05 14:24:45 -05:00
IRQ-affinity.txt
IRQ-domain.txt IRQCHIP: Update docs regarding irq_domain_add_tree() 2015-04-01 17:21:35 +02:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kasan.txt Merge branch 'doc/4.2' into docs-next 2015-06-08 17:04:11 -06:00
kernel-doc-nano-HOWTO.txt Documenation: Update location of docproc.c 2015-07-14 12:36:39 -06:00
kernel-docs.txt
kernel-parameters.txt NFS client updates for Linux 4.3 2015-09-07 14:02:24 -07:00
kernel-per-CPU-kthreads.txt documentation: Update per-CPU kthreads documentation 2015-02-26 11:57:30 -08:00
kmemcheck.txt Documentation: update the CONFIG_DEBUG_PAGEALLOC description 2015-03-20 07:41:55 -06:00
kmemleak.txt Doc: Change wikipedia's URL from http to https 2015-06-22 10:14:05 -06:00
kobject.txt kobject: grammar fix 2014-12-08 09:07:11 -05:00
kprobes.txt kprobes: Update Documentation/kprobes.txt 2015-03-20 07:41:55 -06:00
kref.txt
kselftest.txt kselftest: Move the docs to the Documentation dir 2014-11-24 10:49:54 -07:00
ldm.txt
local_ops.txt percpu: update local_ops.txt to reflect this_cpu operations 2014-12-13 12:42:53 -08:00
lockup-watchdogs.txt watchdog: add watchdog_cpumask sysctl to assist nohz 2015-06-24 17:49:40 -07:00
logo.gif
logo.txt
lzo.txt Documentation: lzo: document part of the encoding 2014-09-28 11:08:00 +02:00
magic-number.txt Documentation/magic-number: Remove SCC_MAGIC 2015-05-13 15:39:04 -04:00
mailbox.txt Documentation: minor typo fix in mailbox.txt 2015-08-13 18:03:18 -06:00
Makefile Documentation: Remove ZBOOT MMC/SDHI utility and docs 2015-02-24 06:45:25 +09:00
ManagementStyle
md-cluster.txt md-cluster: fix deadlock issue on message lock 2015-08-31 19:41:41 +02:00
md.txt doc:md: fix typo in md.txt. 2015-06-23 06:49:44 -06:00
media-framework.txt
memory-barriers.txt Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-03 15:46:07 -07:00
memory-hotplug.txt mem-hotplug: fix typo in Documentation/memory-hotplug.txt 2015-03-20 07:41:55 -06:00
men-chameleon-bus.txt Documentation: Minor changes to men-chameleon-bus.txt 2015-07-24 15:15:17 +02:00
module-signing.txt modsign: change default key details 2015-04-30 09:35:41 -07:00
mono.txt
nommu-mmap.txt fs: introduce f_op->mmap_capabilities for nommu mmap support 2015-01-20 14:02:58 -07:00
ntb.txt NTB: Rename Intel code names to platform names 2015-07-04 14:09:25 -04:00
numastat.txt
oops-tracing.txt livepatch: kernel: add TAINT_LIVEPATCH 2014-12-22 15:40:48 +01:00
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt
phy.txt phy: core: Add devm_of_phy_get_by_index to phy-core 2015-05-11 21:42:23 +05:30
pi-futex.txt
pinctrl.txt pinctrl: move strict option to pinmux_ops 2015-05-06 14:45:19 +02:00
pnp.txt
preempt-locking.txt x86/fpu: Rename math_state_restore() to fpu__restore() 2015-05-19 15:47:18 +02:00
printk-formats.txt The documentation tree update for 4.1. Numerous fixes, the overdue removal 2015-04-18 11:10:49 -04:00
pwm.txt
ramoops.txt pstore-ram: Allow optional mapping with pgprot_noncached 2014-12-11 13:38:31 -08:00
rbtree.txt
remoteproc.txt remoteproc: introduce rproc_get_by_phandle API 2015-06-16 21:12:52 +03:00
rfkill.txt rfkill: document rfkill module parameters 2015-01-09 23:22:12 +01:00
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt Documentation, split up rtc.txt into documentation and test file 2015-03-24 22:01:58 -06:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
SM501.txt
smsc_ece1099.txt
sparse.txt
stable_api_nonsense.txt
stable_kernel_rules.txt stable: Update documentation to clarify preferred procedure 2015-05-22 09:38:56 -06:00
static-keys.txt jump label, locking/static_keys: Update docs 2015-08-03 11:51:14 +02:00
SubmitChecklist
SubmittingDrivers
SubmittingPatches Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2015-09-01 18:46:42 -07:00
svga.txt
sysfs-rules.txt Documentation/sysfs-rules.txt: Add device attribute error code documentation 2014-09-19 14:44:51 -07:00
sysrq.txt Documentation/sysrq.txt: Mention MIPS TLB dump (x) 2015-09-03 12:07:43 +02:00
this_cpu_ops.txt Docs: this_cpu_ops: remove redundant add forms 2014-09-26 11:03:00 +02:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt vfio: powerpc/spapr: Support Dynamic DMA windows 2015-06-11 15:16:55 +10:00
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt Documentation: mention vme_master_mmap() in VME API 2015-06-12 17:26:56 -07:00
volatile-considered-harmful.txt
workqueue.txt workqueue: fix trivial typo in Documentation/workqueue.txt 2015-05-05 09:50:38 -04:00
xillybus.txt xillybus: Move out of staging 2014-09-23 23:44:16 -07:00
xz.txt
zorro.txt