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authorSeongJae Park <sj@kernel.org>2025-08-28 10:12:39 -0700
committerAndrew Morton <akpm@linux-foundation.org>2025-09-13 16:55:23 -0700
commit7b06c471afc8d82c9c246532b74c4ad4db2890d2 (patch)
tree1f7f58b2241775b535a0ebbf9d1aaa331cd95ade
parent540a2aebc657b02520a8837778dace8608ec4f05 (diff)
Docs/mm/damon/design: document 'address unit' parameter
Add 'addr_unit' parameter description on DAMON design document. Link: https://lkml.kernel.org/r/20250828171242.59810-9-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ze zuo <zuoze1@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--Documentation/mm/damon/design.rst14
1 files changed, 13 insertions, 1 deletions
diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index 2f6ba5c7f4c7..d9d5baa1ec87 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -67,7 +67,7 @@ processes, NUMA nodes, files, and backing memory devices would be supportable.
Also, if some architectures or devices support special optimized access check
features, those will be easily configurable.
-DAMON currently provides below three operation sets. Below two subsections
+DAMON currently provides below three operation sets. Below three subsections
describe how those work.
- vaddr: Monitor virtual address spaces of specific processes
@@ -135,6 +135,18 @@ the interference is the responsibility of sysadmins. However, it solves the
conflict with the reclaim logic using ``PG_idle`` and ``PG_young`` page flags,
as Idle page tracking does.
+Address Unit
+------------
+
+DAMON core layer uses ``unsinged long`` type for monitoring target address
+ranges. In some cases, the address space for a given operations set could be
+too large to be handled with the type. ARM (32-bit) with large physical
+address extension is an example. For such cases, a per-operations set
+parameter called ``address unit`` is provided. It represents the scale factor
+that need to be multiplied to the core layer's address for calculating real
+address on the given address space. Support of ``address unit`` parameter is
+up to each operations set implementation. ``paddr`` is the only operations set
+implementation that supports the parameter.
.. _damon_core_logic: