kernel/mm/damon/reclaim.c, branch linux-rolling-stable

mm/damon: rename min_sz_region of damon_ctx to min_region_sz

2026-03-19T15:15:32Z

[ Upstream commit cc1db8dff8e751ec3ab352483de366b7f23aefe2 ] 'min_sz_region' field of 'struct damon_ctx' represents the minimum size of each DAMON region for the context. 'struct damos_access_pattern' has a field of the same name. It confuses readers and makes 'grep' less optimal for them. Rename it to 'min_region_sz'. Link: https://lkml.kernel.org/r/20260117175256.82826-9-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton Stable-dep-of: c80f46ac228b ("mm/damon/core: disallow non-power of two min_region_sz") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

mm/damon: rename DAMON_MIN_REGION to DAMON_MIN_REGION_SZ

2026-03-19T15:15:32Z

[ Upstream commit dfb1b0c9dc0d61e422905640e1e7334b3cf6f384 ] The macro is for the default minimum size of each DAMON region. There was a case that a reader was confused if it is the minimum number of total DAMON regions, which is set on damon_attrs->min_nr_regions. Make the name more explicit. Link: https://lkml.kernel.org/r/20260117175256.82826-8-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton Stable-dep-of: c80f46ac228b ("mm/damon/core: disallow non-power of two min_region_sz") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

mm/damon/reclaim: use min_sz_region for core address alignment when setting regions

2025-11-17T01:28:10Z

When setting regions in DAMON_RECLAIM, DAMON_MIN_REGION will be applied as the core address alignment, and the monitoring target address ranges would be aligned on DAMON_MIN_REGION * addr_unit. When users 1) set addr_unit to a value larger than 1, and 2) set the monitoring target address range as not aligned on DAMON_MIN_REGION * addr_unit, it will cause DAMON_RECLAIM to operate on unexpectedly large physical address ranges. For example, if the user sets the monitoring target address range to [4, 8) and addr_unit as 1024, the aimed monitoring target address range is [4 KiB, 8 KiB). Assuming DAMON_MIN_REGION is 4096, so resulting target address range will be [0, 4096) in the DAMON core layer address system, and [0, 4 MiB) in the physical address space, which is an unexpected range. To fix the issue, use min_sz_region for core address alignment when setting regions. Link: https://lkml.kernel.org/r/20251020130125.2875164-3-yanquanmin1@huawei.com Fixes: 7db551fcfb2a ("mm/damon/reclaim: support addr_unit for DAMON_RECLAIM") Signed-off-by: Quanmin Yan Reviewed-by: SeongJae Park Cc: Kefeng Wang Cc: ze zuo Signed-off-by: Andrew Morton

mm/damon: add a min_sz_region parameter to damon_set_region_biggest_system_ram_default()

2025-11-17T01:28:09Z

Patch series "mm/damon: fixes for address alignment issues in DAMON_LRU_SORT and DAMON_RECLAIM", v2. In DAMON_LRU_SORT and DAMON_RECLAIM, damon_set_regions() will apply DAMON_MIN_REGION as the core address alignment, and the monitoring target address ranges would be aligned on DAMON_MIN_REGION * addr_unit. When users 1) set addr_unit to a value larger than 1, and 2) set the monitoring target address range as not aligned on DAMON_MIN_REGION * addr_unit, it will cause DAMON_LRU_SORT and DAMON_RECLAIM to operate on unexpectedly large physical address ranges. For example, if the user sets the monitoring target address range to [4, 8) and addr_unit as 1024, the aimed monitoring target address range is [4 KiB, 8 KiB). Assuming DAMON_MIN_REGION is 4096, so resulting target address range will be [0, 4096) in the DAMON core layer address system, and [0, 4 MiB) in the physical address space, which is an unexpected range. To fix the issue, add a min_sz_region parameter to damon_set_region_biggest_system_ram_default() and use it when calling damon_set_regions(), replacing the direct use of DAMON_MIN_REGION. This patch (of 2): In DAMON_LRU_SORT, damon_set_regions() will apply DAMON_MIN_REGION as the core address alignment, and the monitoring target address ranges would be aligned on DAMON_MIN_REGION * addr_unit. When users 1) set addr_unit to a value larger than 1, and 2) set the monitoring target address range as not aligned on DAMON_MIN_REGION * addr_unit, it will cause DAMON_LRU_SORT to operate on unexpectedly large physical address ranges. For example, if the user sets the monitoring target address range to [4, 8) and addr_unit as 1024, the aimed monitoring target address range is [4 KiB, 8 KiB). Assuming DAMON_MIN_REGION is 4096, so resulting target address range will be [0, 4096) in the DAMON core layer address system, and [0, 4 MiB) in the physical address space, which is an unexpected range. To fix the issue, add a min_sz_region parameter to damon_set_region_biggest_system_ram_default() and use it when calling damon_set_regions(), replacing the direct use of DAMON_MIN_REGION. Link: https://lkml.kernel.org/r/20251020130125.2875164-1-yanquanmin1@huawei.com Link: https://lkml.kernel.org/r/20251020130125.2875164-2-yanquanmin1@huawei.com Fixes: 2e0fe9245d6b ("mm/damon/lru_sort: support addr_unit for DAMON_LRU_SORT") Signed-off-by: Quanmin Yan Reviewed-by: SeongJae Park Cc: Kefeng Wang Cc: ze zuo Signed-off-by: Andrew Morton

mm/damon/reclaim: use damon_initialized()

2025-09-21T21:22:38Z

DAMON_RECLAIM 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/20250916033511.116366-4-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/reclaim: support addr_unit for DAMON_RECLAIM

2025-09-21T21:22:33Z

Implement a sysfs file to expose addr_unit for DAMON_RECLAIM users. During parameter application, use the configured addr_unit parameter to perform the necessary initialization. Similar to the core layer, prevent setting addr_unit to zero. It is worth noting that when monitor_region_start and monitor_region_end are unset (i.e., 0), their values will later be set to biggest_system_ram. At that point, addr_unit may not be the default value 1. Although we could divide the biggest_system_ram value by addr_unit, changing addr_unit without setting monitor_region_start/end should be considered a user misoperation. And biggest_system_ram is only within the 0~ULONG_MAX range, system can clearly work correctly with addr_unit=1. Therefore, if monitor_region_start/end are unset, always silently reset addr_unit to 1. Link: https://lkml.kernel.org/r/20250910113221.1065764-3-yanquanmin1@huawei.com Signed-off-by: Quanmin Yan Reviewed-by: SeongJae Park Cc: Kefeng Wang Cc: ze zuo Signed-off-by: Andrew Morton

mm/damon/reclaim: avoid divide-by-zero in damon_reclaim_apply_parameters()

2025-09-04T00:10:37Z

When creating a new scheme of DAMON_RECLAIM, the calculation of 'min_age_region' uses 'aggr_interval' as the divisor, which may lead to division-by-zero errors. Fix it by directly returning -EINVAL when such a case occurs. Link: https://lkml.kernel.org/r/20250827115858.1186261-3-yanquanmin1@huawei.com Fixes: f5a79d7c0c87 ("mm/damon: introduce struct damos_access_pattern") Signed-off-by: Quanmin Yan Reviewed-by: SeongJae Park Cc: Kefeng Wang Cc: ze zuo Cc: [6.1+] Signed-off-by: Andrew Morton

mm/damon/reclaim: use damon_call() repeat mode instead of damon_callback

2025-07-20T01:59:54Z

DAMON_RECLAIM uses damon_callback for periodically reading and writing DAMON internal data and parameters. Use its alternative, damon_call() repeat mode. Link: https://lkml.kernel.org/r/20250712195016.151108-5-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/reclaim: use parameter context correctly

2025-07-13T23:38:34Z

damon_reclaim_apply_parameters() allocates a new DAMON context, stages user-specified DAMON parameters on it, and commits to running DAMON context at once, using damon_commit_ctx(). The code is mistakenly over-writing the monitoring attributes and the reclaim scheme on the running context. It is not causing a real problem for monitoring attributes, but the scheme overwriting can remove scheme's internal status such as charged quota. Fix the wrong use of the parameter context. Link: https://lkml.kernel.org/r/20250706193207.39810-7-sj@kernel.org Fixes: 11ddcfc257a3 ("mm/damon/reclaim: use damon_commit_ctx()") Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/reclaim: reset enabled when DAMON start failed

2025-07-13T23:38:34Z

When the startup fails, 'enabled' parameter is not reset. As a result, users show the parameter 'Y' while it is not really working. Fix it by resetting 'enabled' to 'false' when the work is failed. Link: https://lkml.kernel.org/r/20250706193207.39810-5-sj@kernel.org Fixes: 04e98764befa ("mm/damon/reclaim: enable and disable synchronously") Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton