mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-08-26 10:49:33 +00:00
Code Issues Releases Wiki Activity

Docs/admin-guide/mm/damon/usage: document DAMOS filters of sysfs

Browse source 
Document about the newly added files for DAMOS filters on the DAMON usage
document.

Link: https://lkml.kernel.org/r/20221205230830.144349-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
SeongJae Park 2022-12-05 23:08:29 +00:00 committed by Andrew Morton
parent 553b014244
commit 9b7f9322a5
1 changed files with 46 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

48
Documentation/admin-guide/mm/damon/usage.rst
View file

@ -87,6 +87,8 @@ comma (","). ::
│ │ │ │ │ │ │ quotas/ms,bytes,reset_interval_ms
│ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil
│ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low
│ │ │ │ │ │ │ filters/nr_filters
│ │ │ │ │ │ │ │ 0/type,matching,memcg_id
│ │ │ │ │ │ │ stats/nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds
│ │ │ │ │ │ │ tried_regions/
│ │ │ │ │ │ │ │ 0/start,end,nr_accesses,age
@ -151,6 +153,8 @@ number (``N``) to the file creates the number of child directories named as
moment, only one context per kdamond is supported, so only ``0`` or ``1`` can
be written to the file.
.. _sysfs_contexts:
contexts/<N>/
-------------
@ -268,8 +272,8 @@ schemes/<N>/
------------
In each scheme directory, five directories (``access_pattern``, ``quotas``,
``watermarks``, ``stats``, and ``tried_regions``) and one file (``action``)
exist.
``watermarks``, ``filters``, ``stats``, and ``tried_regions``) and one file
(``action``) exist.
The ``action`` file is for setting and getting what action you want to apply to
memory regions having specific access pattern of the interest. The keywords
@ -347,6 +351,46 @@ as below.
The ``interval`` should written in microseconds unit.
schemes/<N>/filters/
--------------------
Users could know something more than the kernel for specific types of memory.
In the case, users could do their own management for the memory and hence
doesn't want DAMOS bothers that. Users could limit DAMOS by setting the access
pattern of the scheme and/or the monitoring regions for the purpose, but that
can be inefficient in some cases. In such cases, users could set non-access
pattern driven filters using files in this directory.
In the beginning, this directory has only one file, ``nr_filters``. Writing a
number (``N``) to the file creates the number of child directories named ``0``
to ``N-1``. Each directory represents each filter. The filters are evaluated
in the numeric order.
Each filter directory contains three files, namely ``type``, ``matcing``, and
``memcg_path``. You can write one of two special keywords, ``anon`` for
anonymous pages, or ``memcg`` for specific memory cgroup filtering. In case of
the memory cgroup filtering, you can specify the memory cgroup of the interest
by writing the path of the memory cgroup from the cgroups mount point to
``memcg_path`` file. You can write ``Y`` or ``N`` to ``matching`` file to
filter out pages that does or does not match to the type, respectively. Then,
the scheme's action will not be applied to the pages that specified to be
filtered out.
For example, below restricts a DAMOS action to be applied to only non-anonymous
pages of all memory cgroups except ``/having_care_already``.::
# echo 2 > nr_filters
# # filter out anonymous pages
echo anon > 0/type
echo Y > 0/matching
# # further filter out all cgroups except one at '/having_care_already'
echo memcg > 1/type
echo /having_care_already > 1/memcg_path
echo N > 1/matching
Note that filters could be ignored depend on the running DAMON operations set
`implementation <sysfs_contexts>`.
.. _sysfs_schemes_stats:
schemes/<N>/stats/