kernel/git/stable/linux.git/mm/damon/tests, branch linux-7.2.y

MAINTAINERS: s/SeongJae/SJ/

2026-07-09T22:48:53+00:00

My legal and preferred first names are SeongJae and SJ, respectively. I was using the legal name for commits and tags, while using the preferred name for conversations. It sometimes confuses people including myself. Consistently use the preferred name. Together remove copyright notes on files. Those are only confusing for people who are not familiar with the law. Meanwhile, we can infer the information in a better way from git logs and public information. Link: https://lore.kernel.org/20260630013820.143366-1-sj@kernel.org Signed-off-by: SJ Park Acked-by: Lorenzo Stoakes Acked-by: David Hildenbrand (Arm) Cc: Liam R. Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/damon/tests/core-kunit: add damon_set_regions() test cases

2026-06-04T21:45:01+00:00

damon_set_regions() is one of the main DAMON kernel API functions that set up the monitoring target memory region boundaries. Implement unit tests for verifying its basic functionalities. Link: https://lore.kernel.org/20260522154026.80546-11-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: Shuah Khan Signed-off-by: Andrew Morton

mm/damon/tests/vaddr-kunit: replace damon_add_region() with damon_set_regions()

2026-06-04T21:45:00+00:00

DAMON virtual address operation set (vaddr) unit tests is using damon_add_region() for setup of DAMON monitoring target region boundaries setup. But, damon_set_regions() is designed for exactly the purpose. All other DAMON API callers use the function for the purpose. Replace damon_add_region() usage in the unit tests with damon_set_regions(), for unifying the use case and reducing the maintenance cost. Link: https://lore.kernel.org/20260522154026.80546-5-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: Shuah Khan Signed-off-by: Andrew Morton

mm/damon: replace damon_rand() with a per-ctx lockless PRNG

2026-06-02T22:22:09+00:00

damon_rand() on the sampling_addr hot path called get_random_u32_below(), which takes a local_lock_irqsave() around a per-CPU batched entropy pool and periodically refills it with ChaCha20. At elevated nr_regions counts (20k+), the lock_acquire / local_lock pair plus __get_random_u32_below() dominate kdamond perf profiles. Replace the helper with a lockless lfsr113 generator (struct rnd_state) held per damon_ctx and seeded from get_random_u64() in damon_new_ctx(). kdamond is the single consumer of a given ctx, so no synchronization is required. Range mapping uses traditional reciprocal multiplication, similar as get_random_u32_below(); for spans larger than U32_MAX (only reachable on 64-bit) the slow path combines two u32 outputs and uses mul_u64_u64_shr() at 64-bit width. On 32-bit the slow path is dead code and gets eliminated by the compiler. The new helper takes a ctx parameter; damon_split_regions_of() and the kunit tests that call it directly are updated accordingly. lfsr113 is a linear PRNG and MUST NOT be used for anything security-sensitive. DAMON's sampling_addr is not exposed to userspace and is only consumed as a probe point for PTE accessed-bit sampling, so a non-cryptographic PRNG is appropriate here. Tested with paddr monitoring and max_nr_regions=20000: kdamond CPU usage reduced from ~72% to ~50% of one core. Link: https://lore.kernel.org/20260505145212.108644-1-jiayuan.chen@linux.dev Link: https://lore.kernel.org/damon/20260426173346.86238-1-sj@kernel.org/T/#m4f1fd74112728f83a41511e394e8c3fef703039c Link: https://lore.kernel.org/20260509011816.85145-1-sj@kernel.org Signed-off-by: Jiayuan Chen Signed-off-by: SeongJae Park Reviewed-by: SeongJae Park Cc: Shu Anzai Cc: Quanmin Yan Signed-off-by: Andrew Morton

mm/damon/tests/core-kunit: test pause commitment

2026-05-29T04:04:59+00:00

Add a kunit test for commitment of damon_ctx->pause parameter that can be done using damon_commit_ctx(). Link: https://lore.kernel.org/20260427151231.113429-7-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Hildenbrand Cc: Jonathan Corbet Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/damon/tests/core-kunit: test fail_charge_{num,denom} committing

2026-05-29T04:04:44+00:00

Extend damos_test_commit_quotas() kunit test to ensure damos_commit_quota() handles fail_charge_{num,denom} parameters. Link: https://lore.kernel.org/20260428013402.115171-9-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Hildenbrand Cc: Jonathan Corbet Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/damon/tests/core-kunit: test goal_tuner commit

2026-04-05T20:53:26+00:00

Extend damos_commit_quota() kunit test for the newly added goal_tuner parameter. Link: https://lkml.kernel.org/r/20260310010529.91162-9-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/tests/core-kunit: add a test for damon_is_last_region()

2026-04-05T20:53:22+00:00

There was a bug [1] in damon_is_last_region(). Add a kunit test to not reintroduce the bug. Link: https://lkml.kernel.org/r/20260307195356.203753-3-sj@kernel.org Link: https://lore.kernel.org/20260114152049.99727-1-sj@kernel.org/ [1] Signed-off-by: SeongJae Park Tested-by: wang lian Reviewed-by: wang lian Cc: Brendan Higgins Cc: David Gow Cc: David Hildenbrand Cc: Jonathan Corbet Cc: Liam Howlett Cc: Lorenzo Stoakes (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/damon/tests/core-kunit: add a test for damon_commit_ctx()

2026-04-05T20:53:21+00:00

Patch series "mm/damon: test and document power-of-2 min_region_sz requirement". Since commit c80f46ac228b ("mm/damon/core: disallow non-power of two min_region_sz"), min_region_sz is always restricted to be a power of two. Add a kunit test to confirm the functionality. Also, the change adds a restriction to addr_unit parameter. Clarify it on the document. This patch (of 2): Add a kunit test for confirming the change that is made on commit c80f46ac228b ("mm/damon/core: disallow non-power of two min_region_sz") functions as expected. Link: https://lkml.kernel.org/r/20260307194222.202075-2-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Gow Cc: David Hildenbrand Cc: Jonathan Corbet Cc: Liam Howlett Cc: Lorenzo Stoakes (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: SeongJae Park Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton

mm/damon/tests/.kunitconifg: enable DAMON_DEBUG_SANITY

2026-04-05T20:53:21+00:00

CONFIG_DAMON_DEBUG_SANITY is recommended for DAMON development and test setups. Enable it on the default configurations for DAMON kunit test run. Link: https://lkml.kernel.org/r/20260306152914.86303-10-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Gow Cc: Shuah Khan Signed-off-by: Andrew Morton