kernel/linux.git/Documentation/scheduler, branch master

Merge tag 'sched_ext-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext

2026-04-15T17:54:24+00:00

Pull sched_ext updates from Tejun Heo: - cgroup sub-scheduler groundwork Multiple BPF schedulers can be attached to cgroups and the dispatch path is made hierarchical. This involves substantial restructuring of the core dispatch, bypass, watchdog, and dump paths to be per-scheduler, along with new infrastructure for scheduler ownership enforcement, lifecycle management, and cgroup subtree iteration The enqueue path is not yet updated and will follow in a later cycle - scx_bpf_dsq_reenq() generalized to support any DSQ including remote local DSQs and user DSQs Built on top of this, SCX_ENQ_IMMED guarantees that tasks dispatched to local DSQs either run immediately or get reenqueued back through ops.enqueue(), giving schedulers tighter control over queueing latency Also useful for opportunistic CPU sharing across sub-schedulers - ops.dequeue() was only invoked when the core knew a task was in BPF data structures, missing scheduling property change events and skipping callbacks for non-local DSQ dispatches from ops.select_cpu() Fixed to guarantee exactly one ops.dequeue() call when a task leaves BPF scheduler custody - Kfunc access validation moved from runtime to BPF verifier time, removing runtime mask enforcement - Idle SMT sibling prioritization in the idle CPU selection path - Documentation, selftest, and tooling updates. Misc bug fixes and cleanups * tag 'sched_ext-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (134 commits) tools/sched_ext: Add explicit cast from void* in RESIZE_ARRAY() sched_ext: Make string params of __ENUM_set() const tools/sched_ext: Kick home CPU for stranded tasks in scx_qmap sched_ext: Drop spurious warning on kick during scheduler disable sched_ext: Warn on task-based SCX op recursion sched_ext: Rename scx_kf_allowed_on_arg_tasks() to scx_kf_arg_task_ok() sched_ext: Remove runtime kfunc mask enforcement sched_ext: Add verifier-time kfunc context filter sched_ext: Drop redundant rq-locked check from scx_bpf_task_cgroup() sched_ext: Decouple kfunc unlocked-context check from kf_mask sched_ext: Fix ops.cgroup_move() invocation kf_mask and rq tracking sched_ext: Track @p's rq lock across set_cpus_allowed_scx -> ops.set_cpumask sched_ext: Add select_cpu kfuncs to scx_kfunc_ids_unlocked sched_ext: Drop TRACING access to select_cpu kfuncs selftests/sched_ext: Fix wrong DSQ ID in peek_dsq error message sched_ext: Documentation: improve accuracy of task lifecycle pseudo-code selftests/sched_ext: Improve runner error reporting for invalid arguments sched_ext: Documentation: Fix scx_bpf_move_to_local kfunc name sched_ext: Documentation: Add ops.dequeue() to task lifecycle tools/sched_ext: Fix off-by-one in scx_sdt payload zeroing ...

Merge tag 'docs-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux

2026-04-14T15:47:08+00:00

Pull documentation updates from Jonathan Corbet: "A busier cycle than I had expected for docs, including: - Translations: some overdue updates to the Japanese translations, Chinese translations for some of the Rust documentation, and the beginnings of a Portuguese translation. - New documents covering CPU isolation, managed interrupts, debugging Python gbb scripts, and more. - More tooling work from Mauro, reducing docs-build warnings, adding self tests, improving man-page output, bringing in a proper C tokenizer to replace (some of) the mess of kernel-doc regexes, and more. - Update and synchronize changes.rst and scripts/ver_linux, and put both into alphabetical order. ... and a long list of documentation updates, typo fixes, and general improvements" * tag 'docs-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux: (162 commits) Documentation: core-api: real-time: correct spelling doc: Add CPU Isolation documentation Documentation: Add managed interrupts Documentation: seq_file: drop 2.6 reference docs/zh_CN: update rust/index.rst translation docs/zh_CN: update rust/quick-start.rst translation docs/zh_CN: update rust/coding-guidelines.rst translation docs/zh_CN: update rust/arch-support.rst translation docs/zh_CN: sync process/2.Process.rst with English version docs/zh_CN: fix an inconsistent statement in dev-tools/testing-overview tracing: Documentation: Update histogram-design.rst for fn() handling docs: sysctl: Add documentation for /proc/sys/xen/ Docs: hid: intel-ish-hid: make long URL usable Documentation/kernel-parameters: fix architecture alignment for pt, nopt, and nobypass sched/doc: Update yield_task description in sched-design-CFS Documentation/rtla: Convert links to RST format docs: fix typos and duplicated words across documentation docs: fix typo in zoran driver documentation docs: add an Assisted-by mention to submitting-patches.rst Revert "scripts/checkpatch: add Assisted-by: tag validation" ...

sched_ext: Documentation: improve accuracy of task lifecycle pseudo-code

2026-04-10T08:30:52+00:00

* Add ops.quiescent() and ops.runnable() to the sched_change path. When a queued task has one of its scheduling properties changed (e.g. nice, affinity), it goes through dequeue() -> quiescent() -> (property change callback, e.g. ops.set_weight()) -> runnable() -> enqueue(). * Change && to || in ops.enqueue() condition. We want to enqueue tasks that have a non-zero slice and are not in any DSQ. * Call ops.dispatch() and ops.dequeue() only for tasks that have had ops.enqueue() called. This is to account for tasks direct-dispatched from ops.select_cpu(). * Add a note explaining that the pseudo-code provides a simplified view of the task lifecycle and list some examples of cases that the pseudo-code does not account for. Fixes: a4f61f0a1afd ("sched_ext: Documentation: Add ops.dequeue() to task lifecycle") Signed-off-by: Kuba Piecuch Reviewed-by: Andrea Righi Signed-off-by: Tejun Heo

sched/doc: Update yield_task description in sched-design-CFS

2026-04-09T14:26:38+00:00

The yield_task description referenced the long-removed compat_yield sysctl and described the function as a dequeue/enqueue cycle. Update it to reflect current behavior: yielding the CPU by moving the current task's position back in the runqueue. Sync zh_CN and sp_SP translations. Signed-off-by: fangqiurong Signed-off-by: Jonathan Corbet Message-ID: <20260403055806.358921-1-user@fqr-pc>

sched_ext: Documentation: Fix scx_bpf_move_to_local kfunc name

2026-04-07T18:13:47+00:00

The correct kfunc name is scx_bpf_dsq_move_to_local(), not scx_bpf_move_to_local(). Fix the two references in the Scheduling Cycle section. Signed-off-by: fangqiurong Signed-off-by: Tejun Heo

sched_ext: Documentation: Add ops.dequeue() to task lifecycle

2026-04-06T18:06:37+00:00

Document ops.dequeue() in the sched_ext task lifecycle now that its semantics are well-defined. Also update the pseudo-code to use task_is_runnable() consistently and clarify the case where ops.dispatch() does not refill the time slice. Signed-off-by: Andrea Righi Reviewed-by: Emil Tsalapatis Signed-off-by: Tejun Heo

sched_ext: Documentation: Clarify ops.dispatch() role in task lifecycle

2026-03-26T00:01:14+00:00

ops.dispatch() is invoked when a CPU becomes available. This can occur when a task voluntarily yields the CPU, exhausts its time slice, or is preempted for other reasons. If the task is still runnable, refilling its time slice in ops.dispatch() (either by the BPF scheduler or the sched_ext core) allows it to continue running without triggering ops.stopping(). However, this behavior is not clearly reflected in the current task lifecycle diagram. Update the diagram to better represent this interaction. Fixes: 9465f44d2df2 ("sched_ext: Documentation: Clarify time slice handling in task lifecycle") Cc: stable@vger.kernel.org # v6.17+ Signed-off-by: Andrea Righi Signed-off-by: Tejun Heo

sched_ext: Documentation: Document events sysfs file and module parameters

2026-03-21T18:32:41+00:00

Two categories of sched_ext diagnostics are currently undocumented: 1. Per-scheduler events sysfs file Each active BPF scheduler exposes a set of diagnostic counters at /sys/kernel/sched_ext//events. These counters are defined (with detailed comments) in kernel/sched/ext_internal.h but have no corresponding documentation in sched-ext.rst. BPF scheduler developers must read kernel source to understand what each counter means. Add a description of the events file, an example of its output, and a brief explanation of every counter. 2. Module parameters kernel/sched/ext.c registers two parameters under the sched_ext. prefix (slice_bypass_us, bypass_lb_intv_us) via module_param_cb() with MODULE_PARM_DESC() strings, but sched-ext.rst makes no mention of them. Users who need to tune bypass-mode behavior have no in-tree documentation to consult. Add a "Module Parameters" section documenting both knobs: their default values, valid ranges (taken from the set_*() validators in ext.c), and the note from the source that they are primarily for debugging. No functional changes. Signed-off-by: zhidao su Signed-off-by: Tejun Heo

sched/deadline: document new sched_getattr() feature for retrieving current parameters for DEADLINE tasks

2026-03-09T16:16:47+00:00

Document in Documentation/sched/sched-deadline.rst the new capability of sched_getattr() to retrieve, for DEADLINE tasks, the runtime left and absolute deadline (setting the flags syscall parameter to 1), in addition to the static parameters (obtained with flags=0). Signed-off-by: Tommaso Cucinotta Acked-by: Juri Lelli Signed-off-by: Jonathan Corbet Message-ID: <20260304102843.1373905-2-tommaso.cucinotta@santannapisa.it>

Merge branch 'for-7.0-fixes' into for-7.1

2026-03-07T14:57:53+00:00

Pull in 57ccf5ccdc56 ("sched_ext: Fix enqueue_task_scx() truncation of upper enqueue flags") which conflicts with ebf1ccff79c4 ("sched_ext: Fix ops.dequeue() semantics"). Signed-off-by: Tejun Heo # Conflicts: # kernel/sched/ext.c