+ docs-mm-damon-design-document-fail_charge_numdenom.patch added to mm-new branch

+ docs-mm-damon-design-document-fail_charge_numdenom.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: Docs/mm/damon/design: document fail_charge_{num,denom}
has been added to the -mm mm-new branch.  Its filename is
     docs-mm-damon-design-document-fail_charge_numdenom.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/docs-mm-damon-design-document-fail_charge_numdenom.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: Docs/mm/damon/design: document fail_charge_{num,denom}
Date: Mon, 27 Apr 2026 18:33:54 -0700

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>
---

 Documentation/mm/damon/design.rst |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

--- a/Documentation/mm/damon/design.rst~docs-mm-damon-design-document-fail_charge_numdenom
+++ a/Documentation/mm/damon/design.rst
@@ -576,6 +576,28 @@ interface <sysfs_interface>`, refer to :
 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
_

Patches currently in -mm which might be from sj@kernel.org are

mm-damon-sysfs-schemes-call-missing-mem_cgroup_iter_break.patch
mm-damon-fix-damos_stat-tracepoint-format-for-sz_applied.patch
mm-damon-core-make-charge_addr_from-aware-of-end-address-exclusivity.patch
docs-mm-damon-maintainer-profile-add-ai-review-usage-guideline.patch
mm-damon-core-introduce-damon_ctx-paused.patch
mm-damon-sysfs-add-pause-file-under-context-dir.patch
docs-mm-damon-design-update-for-context-pause-resume-feature.patch
docs-admin-guide-mm-damon-usage-update-for-pause-file.patch
docs-abi-damon-update-for-pause-sysfs-file.patch
mm-damon-tests-core-kunit-test-pause-commitment.patch
selftests-damon-_damon_sysfs-support-pause-file-staging.patch
selftests-damon-drgn_dump_damon_status-dump-pause.patch
selftests-damon-sysfspy-check-pause-on-assert_ctx_committed.patch
selftests-damon-sysfspy-pause-damon-before-dumping-status.patch
mm-damon-core-handle-min_region_sz-remaining-quota-as-empty.patch
mm-damon-core-merge-regions-after-applying-damos-schemes.patch
mm-damon-core-introduce-failed-region-quota-charge-ratio.patch
mm-damon-sysfs-schemes-implement-fail_charge_numdenom-files.patch
docs-mm-damon-design-document-fail_charge_numdenom.patch
docs-admin-guide-mm-damon-usage-document-fail_charge_numdenom-files.patch
docs-abi-damon-document-fail_charge_numdenom.patch
mm-damon-tests-core-kunit-test-fail_charge_numdenom-committing.patch
selftests-damon-_damon_sysfs-support-failed-region-quota-charge-ratio.patch
selftests-damon-drgn_dump_damon_status-support-failed-region-quota-charge-ratio.patch
selftests-damon-sysfspy-test-failed-region-quota-charge-ratio.patch