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| author | Christian Hansen <chansen3@cisco.com> | 2018-08-18 01:44:59 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-18 02:20:28 +0300 |
| commit | 7f1d23e607185e07e5df2a806a989c24627aef41 (patch) | |
| tree | 3b82f7fbb3039e1072b0b6e212cedfbcacafca92 /Documentation | |
| parent | fadae2953072e9005c5f1d64e1049edb043494dc (diff) | |
| download | linux-7f1d23e607185e07e5df2a806a989c24627aef41.tar.xz | |
tools/vm/page-types.c: include shared map counts
Add a new flag that will read kpagecount for each PFN and print out the
number of times the page is mapped along with the flags in the listing
view.
This information is useful in understanding and optimizing memory usage.
Identifying pages which are not shared allows us to focus on adjusting
the memory layout or access patterns for the sole owning process.
Knowing the number of processes that share a page tells us how many
other times we must make the same adjustments or how many processes to
potentially disable.
Truncated sample output:
voffset map-cnt offset len flags
561a3591e 1 15fe8 1 ___U_lA____Ma_b___________________________
561a3591f 1 2b103 1 ___U_lA____Ma_b___________________________
561a36ca4 1 2cc78 1 ___U_lA____Ma_b___________________________
7f588bb4e 14 2273c 1 __RU_lA____M______________________________
[akpm@linux-foundation.org: coding-style fixes]
[chansen3@cisco.com: add documentation, tweak whitespace]
Link: http://lkml.kernel.org/r/20180705181204.5529-1-chansen3@cisco.com
Link: http://lkml.kernel.org/r/20180612153205.12879-1-chansen3@cisco.com
Signed-off-by: Christian Hansen <chansen3@cisco.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/mm/pagemap.rst | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst index 577af85beb41..3f7bade2c231 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -44,6 +44,9 @@ There are four components to pagemap: * ``/proc/kpagecount``. This file contains a 64-bit count of the number of times each page is mapped, indexed by PFN. +The page-types tool in the tools/vm directory can be used to query the +number of times a page is mapped. + * ``/proc/kpageflags``. This file contains a 64-bit set of flags for each page, indexed by PFN. |