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| author | SeongJae Park <sj@kernel.org> | 2026-04-27 18:33:54 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-05-28 21:04:43 -0700 |
| commit | 776270536d9d2111aec3db54cfccae4ed5a3c5f6 (patch) | |
| tree | 81f346f1515d8306cb7d5cfc6781fe5930163be3 /Documentation | |
| parent | fad1124120d61d2c6781c9d0fcace0fdb6e24df4 (diff) | |
| download | linux-next-history-776270536d9d2111aec3db54cfccae4ed5a3c5f6.tar.gz | |
Docs/mm/damon/design: document fail_charge_{num,denom}
Update DAMON design document for the DAMOS action failed region quota
charge ratio.
Link: https://lore.kernel.org/20260428013402.115171-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/mm/damon/design.rst | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst index afc7d52bda2f7..bacb457f553a1 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -565,6 +565,28 @@ interface <sysfs_interface>`, refer to :ref:`weights <sysfs_quotas>` part of the documentation. +.. _damon_design_damos_quotas_failed_memory_charging_ratio: + +Action-failed Memory Charging Ratio +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +DAMOS action to a given region can fail for some subsets of the memory of the +region. For example, if the action is ``pageout`` and the region has some +unreclaimable pages, applying the action to the pages will fail. The amount of +system resource that is taken for such failed action applications is usually +different from that for successful action applications. For such cases, users +can set different charging ratio for such failed memory. The ratio can be +specified using ``fail_charge_num`` and ``fail_charge_denom`` parameters. The +two parameters represent the numerator and denominator of the ratio. The +feature is enabled only if ``fail_charge_denom`` is not zero. + +For example, let's suppose a DAMOS action is applied to a region of 1,000 MiB +size. The action is successfully applied to only 700 MiB of the region. +``fail_charge_num`` and ``fail_charge_denom`` are set to ``1`` and ``1024``, +respectively. Then only 700 MiB and 300 KiB of size (``700 MiB + 300 MiB * 1 / +1024``) will be charged. + + .. _damon_design_damos_quotas_auto_tuning: Aim-oriented Feedback-driven Auto-tuning |