linux-next.git/tools/testing/selftests/cgroup, branch master

selftests/cgroup: Fix minor defects in test_cpuset

2026-07-17T22:12:44+00:00

With commit 98149f542530 ("selftests/cgroup: Add test for cpuset affinity on controller disable"), sashiko [1] reported 3 different issues with the new test_cpuset_affinity_on_controller_disable() test. 1) `cpu_set_equal` iterates over mask bytes instead of bits, ignoring CPUs >= 8. 2) Thread synchronization logic allows the main thread to read uninitialized stack memory, causing test flakiness. 3) Test fails instead of skipping gracefully on uniprocessor systems or when CPU 1 is unavailable. Fix the reported issues by: 1) Iterates over the bit size of the mask. 2) Test the new ready flag for each thread to end the wait on the conditional variable and eliminate the now unneeded AFFINITY_THREAD_A_READY and AFFINITY_THREADS_READY test phases. 3) Return KSFT_SKIP on "cpuset.cpus" setting failure. [1] https://sashiko.dev/#/patchset/20260712235510.373125-1-longman%40redhat.com Fixes: 98149f542530 ("selftests/cgroup: Add test for cpuset affinity on controller disable") Signed-off-by: Waiman Long Signed-off-by: Tejun Heo

selftests/cgroup: Remove redundant cg_enter_current() call in test_core

2026-07-17T17:05:40+00:00

The test_cgcore_no_internal_process_constraint_on_threads test has two back-to-back cg_enter_current(root) calls in its cleanup path. A single cg_enter_current() call atomically migrates the entire thread group to the target cgroup even for multi-threaded processes, and this test creates no extra threads or child processes that would require a second migration attempt. The second call is a harmless no-op once the process is already in the root cgroup, but it is redundant and inconsistent with the cleanup logic used in all other cgroup core selftest cases. Remove the duplicate call to clean up the code. No functional change is intended. Signed-off-by: Jian Guo Acked-by: Michal Koutný Tested-by: Tao Cui Signed-off-by: Tejun Heo

selftests/cgroup: Add test for cpuset affinity on controller disable

2026-07-16T19:38:22+00:00

Add a new selftest that exposes a bug in cpuset_attach() where thread CPU affinity is not properly updated when the cpuset controller is disabled in a threaded cgroup hierarchy. The test creates a threaded cgroup hierarchy with two child cgroups (A and B) having different cpuset.cpus constraints: - Parent: cpuset.cpus=0-1 - Child A: cpuset.cpus=0-1 - Child B: cpuset.cpus=1 (restricted to CPU 1 only) A multithreaded process is created with threads placed in different cgroups. When the cpuset controller is disabled on the parent, thread affinities should be updated to match the parent's cpuset. Expected behavior: - thread_a affinity: {0-1} before and after (unchanged) - thread_b affinity: {1} before, {0-1} after (expanded) Current buggy behavior: - thread_b affinity remains {1} after controller disable Assisted-by: Claude:claude-sonnet-4-5 Signed-off-by: Michal Koutný Acked-by: Waiman Long Signed-off-by: Tejun Heo

selftests/cgroup: fix missing TAP output in test_hugetlb_memcg

2026-07-14T21:42:10+00:00

main() in test_hugetlb_memcg never calls ksft_print_header(), ksft_set_plan(), or ksft_finished(), so its output has no TAP plan and is not valid TAP, unlike the sibling test_memcontrol and test_kmem tests. Add the header/plan/finished calls following the same pattern. Signed-off-by: Song Hu Reviewed-by: Tao Cui Signed-off-by: Tejun Heo

selftests/cgroup: Adjust cpu test duration based on HZ

2026-06-29T18:52:56+00:00

For lower HZ values a quota of 1000us is much lower than the amount of microseconds per tick which makes the tests test_cpucg_max and test_cpugc_max_nested fail. Increase the test duration to accommodate for lower HZ values. Link: https://lore.kernel.org/lkml/20260625203307.1114538-1-joest@redhat.com/ Signed-off-by: Joe Simmons-Talbott Acked-by: Michal Koutný Signed-off-by: Tejun Heo

cgroup/cpuset: Avoid unnecessary cpus & mems update in cpuset_hotplug_update_tasks()

2026-06-24T19:41:37+00:00

As reported by sashiko [1], cpuset_hotplug_update_tasks() may perform unnecessary task iteration and updating of tasks' CPU and node masks when mems_allowed and/or cpus_allowed are not set in cpuset v2. It is due to the fact that the temporary new_cpus and new_mems masks do not inherit parent's effective_cpus/mems when they are empty which is the expected behavior for cpuset v2 since commit 4ec22e9c5a90 ("cpuset: Enable cpuset controller in default hierarchy"). Fix that and avoid unnecessary work by enhancing compute_effective_cpumask() to add the empty cpumask check and inheriting the parent's versions if empty when in v2. A new compute_effective_nodemask() helper is also added to perform a similar function for new effective_mems. Add new test_cpuset_prs.sh test cases to confirm that effective_cpus will inherit the parent's version if cpuset.cpus is empty. [1] https://sashiko.dev/#/patchset/20260621032816.1806773-1-longman%40redhat.com Suggested-by: Ridong Chen Fixes: 4ec22e9c5a90 ("cpuset: Enable cpuset controller in default hierarchy") Signed-off-by: Waiman Long Reviewed-by: Ridong Chen Signed-off-by: Tejun Heo

Merge tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-06-19T17:14:34+00:00

Pull MM updates from Andrew Morton: - "selftests/mm: clean up build output and verbosity" (Li Wang) Remove some noise from the MM selftests build - "mm: Free contiguous order-0 pages efficiently" (Ryan Roberts) Speed up the freeing of a batch of 0-order pages by first scanning them for coalescing opportunities. This is applicable to vfree() and to the releasing of frozen pages - "mm/damon: introduce DAMOS failed region quota charge ratio" (SeongJae Park) Address a DAMOS usability issue: The DAMOS quota often exhausts prematurely because it charges for all memory attempted, causing slow and inconsistent performance when actions fail on unreclaimable memory. To fix this, a new feature lets users set a smaller, flexible quota charge ratio (via a numerator and denominator) for failed regions. Since failed actions cause less overhead, reducing their quota cost ensures more predictable and efficient DAMOS processing - "selftests/cgroup: improve zswap tests robustness and support large page sizes" (Li Wang) Fix various spurious failures and improves the overall robustness of the cgroup zswap selftests - "fix MAP_DROPPABLE not supported errno" (Anthony Yznaga) Fix an issue in the mlock selftests on arm32 - "mm: huge_memory: clean up defrag sysfs with shared" (Breno Leitao) Some maintenance work in the huge_memory code - "treewide: fixup gfp_t printks" (Brendan Jackman) Use the special vprintf() gfp_t conversion in various places - "mm: Fix vmemmap optimization accounting and initialization" (Muchun Song) Fix several bugs in the vmemmap optimization, mainly around incorrect page accounting and memmap initialization in the DAX and memory hotplug paths. It also fixes pageblock migratetype initialization and struct page initialization for ZONE_DEVICE compound pages - "mm/damon: repost non-hotfix reviewed patches in damon/next tree" A sprinkle of unrelated minor bugfixes for DAMON - "mm: remove page_mapped()" (David Hildenbrand) Remove this function from the tree, replacing it with folio_mapped() - "mm/damon: let DAMON be paused and resumed" (SeongJae Park) Allow DAMON to be paused and resumed without losing its current state - "kasan: hw_tags: Disable tagging for stack and page-tables" (Muhammad Usama Anjum) Simplify and speed up kasan by removing its ineffective tagging of stacks and page tables - "mm/damon/reclaim,lru_sort: monitor all system rams by default" (SeongJae Park) Simplify deployment on diverse hardware like NUMA systems by updating DAMON_RECLAIM and DAMON_LRU_SORT to automatically monitor the physical address range covering all System RAM areas by default, replacing the overly restrictive behavior that only targeted the single largest memory block to save on negligible overhead - "mm/damon/sysfs: document filters/ directory as deprecated" (SeongJae Park) Update some DAMON docs - "mm: use spinlock guards for zone lock" (Dmitry Ilvokhin) Switch zone->lock handling over to using the guard() mechanisms - "mm/filemap: tighten mmap_miss hit accounting" (fujunjie) Fix a flaw where the mmap_miss counter over-credited page cache hits during fault-arounds and page-fault retries. This results in significant reduction of redundant synchronous mmap readahead I/O, drastically cutting down execution time and gigabytes read for sparse random or strided memory access workloads - "selftests/cgroup: Fix false positive failures in test_percpu_basic" (Li Wang) Fix a couple of false-positives in the cgroup kmem selftests - "mm/damon/reclaim: support monitoring intervals auto-tuning" (SeongJae Park) Add a new parameter to DAMON permitting DAMON_RECLAIM to automatically tune DAMON's sampling and aggregation intervals - "mm/damon/stat: add kdamond_pid parameter" (SeongJae Park) Change DAMON_STAT to provide the pid of its kdamond - "mm/kmemleak: dedupe verbose scan output" (Breno Leitao) Remove large amounts of duplicated backtraces from the verbose-mode kmemleak output - "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 1)" (David Hildenbrand) Reduce our use of CONFIG_HAVE_BOOTMEM_INFO_NODE, with a view to removing it entirely in a later series - "mm/damon: validate min_region_size to be power of 2" (Liew Rui Yan) Prevent users from passing a non-power-of-2 value of `addr_unit', as this later results in undesirable behavior - "mm: document read_pages and simplify usage" (Frederick Mayle) - "tools/mm/page-types: Fix misc bugs" (Ye Liu) Fix three issues in tools/mm/page-types.c - "mm: misc cleanups from __GFP_UNMAPPED series" (Brendan Jackman) Implement several cleanups in the page allocator and related code - "mm, swap: swap table phase IV: unify allocation" (Kairui Song) Unify the allocation and charging of anon and shmem swap in folios, provides better synchronization, consolidates the metadata management, hence dropping the static array and map, and improves performance - "mm/damon: introduce data attributes monitoring" (SeongJae Park( Extend DAMON to monitor general data attributes other than accesses - "mm/vmalloc: free unused pages on vrealloc() shrink" (Shivam Kalra) Implement the TODO in vrealloc() to unmap and free unused pages when shrinking across a page boundary - "mm/damon: documentation and comment fixes" (niecheng) - "remove mmap_action success, error hooks" (Lorenzo Stoakes) Eliminate custom hooks from mmap_action by removing the problematic success_hook which allowed drivers to improperly access uninitialized VMAs. It replaces the error_hook with a simple error-code field and updates the memory char driver accordingly - "mm/damon: minor improvements for code readability and tests" (SeongJae Park) - "mm/damon: fix macro arguments and clarify quota goals doc" (Maksym Shcherba) - "userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c" (Mike Rapoport) - "mm/mglru: improve reclaim loop and dirty folio" (Kairui Song and others) Clean up and slightly improves MGLRU's reclaim loop and dirty writeback handling. Large performance improvements are measured - "use vma locks for proc/pid/{smaps|numa_maps} reads" (Suren Baghdasaryan) Use per-vma locks when reading /proc/pid/smaps and numa_maps similar to reduce contention on central mmap_lock - "refactors thpsize_shmem_enabled_store() and thpsize_shmem_enabled_show()" (Ran Xiaokai) Some cleanup work in the THP code - "selftests/memfd: fix compilation warnings" (Konstantin Khorenko) Fix a few build glitches in the memfd selftest code. - "memcg: shrink obj_stock_pcp and cache multiple objcgs" (Shakeel Butt) Resolve a 68% performance regression caused by NUMA-node cache thrashing around struct obj_stock_pcp by shrinking its existing fields and expanding it into a multi-slot array that caches up to five obj_cgroup pointers per CPU, allowing per-node variants of the same memcg to coexist within a single 64-byte cache line. - "zram: writeback fixes" (Sergey Senozhatsky) address a couple of unrelated zram writeback issues - "mm: switch THP shrinker to list_lru" (Johannes Weiner) Resolve NUMA-awareness issues and streamlines callsite interaction by refactoring and extending the list_lru API to completely replace the complex, open-coded deferred split queue for Transparent Huge Pages - "mm: improve large folio readahead for exec memory" (Usama Arif) Improve large-folio readahead on systems like 64K-page arm64 by preventing the mmap_miss check from permanently disabling target-oriented VM_EXEC readahead, and by generalizing the force_thp_readahead gate to support mappings with any usefully large maximum folio order under the cache cap. - "userfaultfd/pagemap: pre-existing fixes" (Kiryl Shutsemau) Fix a bunch of minor issues in the userfaultfd/pagemap, all of which were flagged by Sashiko review of proposed new material - "mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and vmemmap_check_pmd()" (Muchun Song) Provide generic versions of these two functions so the four arch-specific implementations can be removed. - "mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device" (Youngjun Park) Address a uswsusp-vs-swapoff race and reduces the swap device reference taking/releasing frequency. - "mm/hmm: A fix and a selftest" (Dev Jain) * tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) selftests/mm/hmm-tests: test pagemap reads of PMD device-private entries fs/proc/task_mmu: do not warn on seeing non-migration pmd entry lib/test_hmm: check alloc_page_vma() return value and handle OOM mm/compaction: cap compact_gap() at COMPACT_CLUSTER_MAX mm/swap: remove redundant swap device reference in alloc/free mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device mm/filemap: use folio_next_index() for start vmalloc: fix NULL pointer dereference in is_vm_area_hugepages() sparc/mm: drop vmemmap_check_pmd helper and use generic code loongarch/mm: drop vmemmap_check_pmd helper and use generic code riscv/mm: drop vmemmap_pmd helpers and use generic code arm64/mm: drop vmemmap_pmd helpers and use generic code mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd() rust: page: mark Page::nid as inline userfaultfd: build __VMA_UFFD_FLAGS from config-gated masks userfaultfd: gate must_wait writability check on pte_present() mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole() fs/proc/task_mmu: use huge_page_size() in pagemap_scan_hugetlb_entry() fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race ...

Merge tag 'cgroup-for-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2026-06-17T11:03:56+00:00

Pull cgroup updates from Tejun Heo: - Last cycle deferred css teardown on cgroup removal until the cgroup depopulated, so a css is not taken offline while tasks can still reference it. Disabling a controller through cgroup.subtree_control still had the same problem. This reworks the deferral from per-cgroup to per-css so that path is covered too. - New RDMA controller monitoring files: rdma.peak for per-device peak usage and rdma.events / rdma.events.local for resource-limit exhaustion. The max-limit parser was rewritten, fixing two input parsing bugs. - cpuset: fix a sched-domain leak on the domain-rebuild failure path and skip a redundant hardwall ancestor scan on v2. - Misc: pair the remaining lockless cgroup.max.* reads with WRITE_ONCE, assorted selftest robustness fixes, and doc path corrections. * tag 'cgroup-for-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (22 commits) cgroup: Migrate tasks to the root css when a controller is rebound docs: cgroup: Fix stale source file paths cgroup/cpuset: Free sched domains on rebuild guard failure cgroup: pair max limit READ_ONCE() with WRITE_ONCE() selftests/cgroup: enable memory controller in hugetlb memcg test cgroup/rdma: Drop unnecessary READ_ONCE() on event counters cgroup: Defer kill_css_finish() in cgroup_apply_control_disable() cgroup: Add per-subsys-css kill_css_finish deferral cgroup: Move populated counters to cgroup_subsys_state cgroup: Annotate unlocked nr_populated_* accesses with READ_ONCE/WRITE_ONCE cgroup: Inline cgroup_has_tasks() in cgroup.h cgroup/rdma: document rdma.peak, rdma.events and rdma.events.local cgroup/rdma: add rdma.events.local for per-cgroup allocation failure attribution cgroup/rdma: add rdma.events to track resource limit exhaustion cgroup/rdma: add rdma.peak for per-device peak usage tracking selftests/cgroup: check malloc return value in alloc_anon functions cgroup/cpuset: Skip hardwall ancestor scan in cpuset v2 in cpuset_current_node_allowed() selftests/cgroup: fix misleading debug message in test_cgfreezer_time_child selftests/cgroup: fix child process escaping to parent cleanup in test_cpucg_nice selftests/cgroup: Add NULL check after malloc in cgroup_util.c ...

selftests/cgroup: include slab in test_percpu_basic memory check

2026-05-29T04:05:07+00:00

test_percpu_basic() currently compares memory.current against only memory.stat:percpu after creating 1000 child cgroups. Observed failure: #./test_kmem ok 1 test_kmem_basic ok 2 test_kmem_memcg_deletion ok 3 test_kmem_proc_kpagecgroup ok 4 test_kmem_kernel_stacks ok 5 test_kmem_dead_cgroups memory.current 11530240 percpu 8440000 not ok 6 test_percpu_basic That assumption is too strict: child cgroup creation also allocates slab-backed metadata, so memory.current is expected to be larger than percpu alone. One visible path is: cgroup_mkdir() cgroup_create() cgroup_addrm_file() cgroup_add_file() __kernfs_create_file() __kernfs_new_node() kmem_cache_zalloc() These kernfs allocations are charged as slab and show up in memory.stat:slab. Update the check to compare memory.current against (percpu + slab) within MAX_VMSTAT_ERROR, and print slab/delta in the failure message to improve diagnostics. Link: https://lore.kernel.org/20260501022058.18024-3-li.wang@linux.dev Signed-off-by: Li Wang Reviewed-by: Waiman Long Cc: Christoph Lameter Cc: Johannes Weiner Cc: Michal Hocko Cc: Shakeel Butt Cc: Tejun Heo Cc: Vlastimil Babka Cc: Sayali Patil Signed-off-by: Andrew Morton

selftests/cgroup: fix hardcoded page size in test_percpu_basic

2026-05-29T04:05:07+00:00

Patch series "selftests/cgroup: Fix false positive failures in test_percpu_basic", v2. This patch series addresses two separate issues that cause false positive failures in the test_percpu_basic test within the cgroup kmem selftests. The first issue stems from a hardcoded assumption about the system page size, which breaks the test on architectures with larger page sizes. The second issue is an overly strict memory check that fails to account for the slab metadata allocated during cgroup creation. This patch (of 2): MAX_VMSTAT_ERROR uses a hardcoded page size of 4096, which assumes 4K pages. This causes test_percpu_basic to fail on systems where the kernel is configured with a larger page size, such as aarch64 systems using 16K or 64K pages, where the maximum permissible discrepancy between memory.current and percpu charges is proportionally larger. Replace the hardcoded 4096 with sysconf(_SC_PAGESIZE) to correctly derive the page size at runtime regardless of the underlying architecture or kernel configuration. Link: https://lore.kernel.org/20260501022058.18024-1-li.wang@linux.dev Link: https://lore.kernel.org/20260501022058.18024-2-li.wang@linux.dev Signed-off-by: Li Wang Acked-by: Waiman Long Reviewed-by: Sayali Patil Cc: Christoph Lameter Cc: Johannes Weiner Cc: Michal Hocko Cc: Shakeel Butt Cc: Tejun Heo Cc: Vlastimil Babka Signed-off-by: Andrew Morton