linux/tools
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
..
arch tools include: Add basic atomic.h implementation from the kernel sources 2015-05-08 16:11:05 -03:00
build tools build: Allow duplicate objects in the object list 2015-08-26 10:34:58 -03:00
cgroup
firewire
hv tools: hv: add a python script lsvmbus to list VMBus devices 2015-08-05 11:44:29 -07:00
iio iio: lsiio: fix error code handling error 2015-08-12 19:26:22 +01:00
include tools: Restore export.h 2015-08-25 09:44:22 +02:00
laptop/freefall Move freefall program from Documentation/ to tools/ 2015-06-08 16:42:07 -06:00
lguest tools/lguest: Clean up include dir 2015-08-26 06:12:35 +02:00
lib perf/core improvements and fixes: 2015-09-01 10:25:57 +02:00
net bpf_jit_disasm: also support reading jit dump from file 2015-07-31 15:13:14 -07:00
nfsd
perf perf tools: Fix link time error with sample_reg_masks on non x86 2015-09-01 13:04:41 -03:00
power Power management and ACPI material for v4.3-rc1 2015-09-01 19:45:46 -07:00
scripts
testing selftests/userfaultfd: fix compiler warnings on 32-bit 2015-09-08 15:35:28 -07:00
thermal/tmon tools/thermal: tmon: fixed the 'make install' command 2015-05-09 13:36:58 +08:00
time tools: add script to test udelay 2014-07-23 10:16:38 -07:00
usb tools: ffs-aio-example: use endpoint addresses from descriptors 2015-01-15 09:41:49 -06:00
virtio tools/virtio: add virtio 1.0 in vringh_test 2014-12-15 23:49:22 +02:00
vm pagemap: add mmap-exclusive bit for marking pages mapped only here 2015-09-08 15:35:28 -07:00
Makefile Staging driver patches for 4.2-rc1 2015-06-26 15:46:08 -07:00