kernel/linux.git/samples/damon/mtier.c, branch v6.18.22

samples/damon/mtier: use damon_initialized()

2025-09-21T21:22:39+00:00

damon_sample_mtier is assuming DAMON is ready to use in module_init time, and uses its own hack to see if it is the time. Use damon_initialized(), which is a way for seeing if DAMON is ready to be used that is more reliable and better to maintain instead of the hack. Link: https://lkml.kernel.org/r/20250916033511.116366-8-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

samples/damon/mtier: avoid starting DAMON before initialization

2025-09-13T20:05:38+00:00

Commit 964314344eab ("samples/damon/mtier: support boot time enable setup") is somehow incompletely applying the origin patch [1]. It is missing the part that avoids starting DAMON before module initialization. Probably a mistake during a merge has happened. Fix it by applying the missed part again. Link: https://lkml.kernel.org/r/20250909022238.2989-4-sj@kernel.org Link: https://lore.kernel.org/20250706193207.39810-4-sj@kernel.org [1] Fixes: 964314344eab ("samples/damon/mtier: support boot time enable setup") Signed-off-by: SeongJae Park Cc: Signed-off-by: Andrew Morton

samples/damon: support automatic node address detection

2025-07-20T01:59:47+00:00

This patch adds a new knob `detect_node_addresses`, which determines whether the physical address range is set manually using the existing knobs or automatically by the mtier module. When `detect_node_addresses` set to 'Y', mtier automatically converts node0 and node1 to their physical addresses. If set to 'N', it uses the existing 'node#_start_addr' and 'node#_end_addr' to define regions as before. Link: https://lkml.kernel.org/r/20250707235919.513-1-yunjeong.mun@sk.com Signed-off-by: Yunjeong Mun Suggested-by: Honggyu Kim Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton

samples/damon: change enable parameters to enabled

2025-07-20T01:59:47+00:00

The damon_{lru_sort,reclaim,stat} kernel modules use "enabled" parameter knobs as follows. /sys/module/damon_lru_sort/parameters/enabled /sys/module/damon_reclaim/parameters/enabled /sys/module/damon_stat/parameters/enabled However, other sample modules of damon use "enable" parameter knobs so it'd be better to rename them from "enable" to "enabled" to keep the consistency with other damon modules. Before: /sys/module/damon_sample_wsse/parameters/enable /sys/module/damon_sample_prcl/parameters/enable /sys/module/damon_sample_mtier/parameters/enable After: /sys/module/damon_sample_wsse/parameters/enabled /sys/module/damon_sample_prcl/parameters/enabled /sys/module/damon_sample_mtier/parameters/enabled There is no functional changes in this patch. Link: https://lkml.kernel.org/r/20250707024548.1964-1-honggyu.kim@sk.com Signed-off-by: Honggyu Kim Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton

samples/damon/mtier: rename to have damon_sample_ prefix

2025-07-20T01:59:43+00:00

DAMON sample module, mtier has its name 'mtier'. It could conflict with future modules, and not very easy to identify it by name. Use a prefix, "damon_sample_" for the name. Note that this could break users if they depend on the old name. But it is just a sample, so no such usage is expected, or known. Even if such usage exists, updating it for the new name should be straightforward. Link: https://lkml.kernel.org/r/20250705175000.56259-4-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

samples/damon/mtier: support boot time enable setup

2025-07-13T23:38:34+00:00

If 'enable' parameter of the 'mtier' DAMON sample module is set at boot time via the kernel command line, memory allocation is tried before the slab is initialized. As a result kernel NULL pointer dereference BUG can happen. Fix it by checking the initialization status. Link: https://lkml.kernel.org/r/20250706193207.39810-4-sj@kernel.org Fixes: 82a08bde3cf7 ("samples/damon: implement a DAMON module for memory tiering") Signed-off-by: SeongJae Park Cc: Signed-off-by: Andrew Morton

samples/damon/mtier: add parameters for node0 memory usage

2025-07-13T23:38:19+00:00

Change the hard-coded quota goal metric values into sysfs knobs: `node0_mem_used_bp` and `node0_mem_free_bp`. These knobs represent the used and free memory ratio of node0 in basis points (bp, where 1 bp = 0.01%). As mentioned in [1], this patch is developed under the assumption that node0 is always the fast-tier in a two-tiers memory setup. [1] https://lore.kernel.org/linux-mm/20250420194030.75838-8-sj@kernel.org/ Link: https://lkml.kernel.org/r/20250627163329.50997-1-sj@kernel.org Link: https://patch.msgid.link/20250619050313.1535-1-yunjeong.mun@sk.com Signed-off-by: Yunjeong Mun Signed-off-by: SeongJae Park Suggested-by: Honggyu Kim Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton

samples/damon: fix damon sample mtier for start failure

2025-07-10T04:07:55+00:00

The damon_sample_mtier_start() can fail so we must reset the "enable" parameter to "false" again for proper rollback. In such cases, setting Y to "enable" then N triggers the similar crash with mtier because damon sample start failed but the "enable" stays as Y. Link: https://lkml.kernel.org/r/20250702000205.1921-4-honggyu.kim@sk.com Fixes: 82a08bde3cf7 ("samples/damon: implement a DAMON module for memory tiering") Signed-off-by: Honggyu Kim Reviewed-by: SeongJae Park Cc: Signed-off-by: Andrew Morton

samples/damon: implement a DAMON module for memory tiering

2025-05-13T06:50:30+00:00

Implement a sample DAMON module that shows how self-tuned DAMON-based memory tiering can be written. It is a sample since the purpose is to give an idea about how it can be implemented and perform, rather than be used on general production setups. Especially, it supports only two tiers memory setup having only one CPU-attached NUMA node. [sj@kernel.org: fix wrong DAMON attrs setting] Link: https://lkml.kernel.org/r/20250510220932.47722-1-sj@kernel.org [sj@kernel.org: trigger build even if only mtier is enabled] Link: https://lkml.kernel.org/r/20250426184054.11437-1-sj@kernel.org Link: https://lkml.kernel.org/r/20250420194030.75838-8-sj@kernel.org Signed-off-by: SeongJae Park Cc: Jonathan Corbet Cc: Yunjeong Mun Signed-off-by: Andrew Morton