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authorSeongJae Park <sj@kernel.org>2021-11-05 23:46:49 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 23:30:44 +0300
commitc2fe4987ed31c32591c9aea5a1e8e2540ce66e12 (patch)
tree79ebb9cf47ab951679fd65778b9e04a0a71f36d0 /Documentation/admin-guide/mm
parent1c2e11bfa649cc07e6322b0e5ea3cdbada9c43c3 (diff)
downloadlinux-c2fe4987ed31c32591c9aea5a1e8e2540ce66e12.tar.xz
Docs/admin-guide/mm/damon: document 'init_regions' feature
This adds description of the 'init_regions' feature in the DAMON usage document. Link: https://lkml.kernel.org/r/20211012205711.29216-4-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Amit Shah <amit@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rienjes <rientjes@google.com> Cc: David Woodhouse <dwmw@amazon.com> Cc: Greg Thelen <gthelen@google.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Leonard Foerster <foersleo@amazon.de> Cc: Marco Elver <elver@google.com> Cc: Markus Boehme <markubo@amazon.de> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/admin-guide/mm')
-rw-r--r--Documentation/admin-guide/mm/damon/usage.rst41
1 files changed, 39 insertions, 2 deletions
diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index c0296c14babf..f7d5cfbb50c2 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -34,8 +34,9 @@ the reason, this document describes only the debugfs interface
debugfs Interface
=================
-DAMON exports four files, ``attrs``, ``target_ids``, ``schemes`` and
-``monitor_on`` under its debugfs directory, ``<debugfs>/damon/``.
+DAMON exports five files, ``attrs``, ``target_ids``, ``init_regions``,
+``schemes`` and ``monitor_on`` under its debugfs directory,
+``<debugfs>/damon/``.
Attributes
@@ -74,6 +75,42 @@ check it again::
Note that setting the target ids doesn't start the monitoring.
+Initial Monitoring Target Regions
+---------------------------------
+
+In case of the debugfs based monitoring, DAMON automatically sets and updates
+the monitoring target regions so that entire memory mappings of target
+processes can be covered. However, users can want to limit the monitoring
+region to specific address ranges, such as the heap, the stack, or specific
+file-mapped area. Or, some users can know the initial access pattern of their
+workloads and therefore want to set optimal initial regions for the 'adaptive
+regions adjustment'.
+
+In such cases, users can explicitly set the initial monitoring target regions
+as they want, by writing proper values to the ``init_regions`` file. Each line
+of the input should represent one region in below form.::
+
+ <target id> <start address> <end address>
+
+The ``target id`` should already in ``target_ids`` file, and the regions should
+be passed in address order. For example, below commands will set a couple of
+address ranges, ``1-100`` and ``100-200`` as the initial monitoring target
+region of process 42, and another couple of address ranges, ``20-40`` and
+``50-100`` as that of process 4242.::
+
+ # cd <debugfs>/damon
+ # echo "42 1 100
+ 42 100 200
+ 4242 20 40
+ 4242 50 100" > init_regions
+
+Note that this sets the initial monitoring target regions only. In case of
+virtual memory monitoring, DAMON will automatically updates the boundary of the
+regions after one ``regions update interval``. Therefore, users should set the
+``regions update interval`` large enough in this case, if they don't want the
+update.
+
+
Schemes
-------