linux/tools/sched_ext/include, branch master

tools/sched_ext: Add explicit cast from void* in RESIZE_ARRAY()

2026-04-13T16:14:11Z

This fixes the following compilation error when using the header from C++ code: error: assigning to 'struct scx_flux__data_uei_dump *' from incompatible type 'void *' Signed-off-by: Kuba Piecuch Signed-off-by: Tejun Heo

sched_ext: Make string params of __ENUM_set() const

2026-04-13T16:14:05Z

A small change to improve type safety/const correctness. __COMPAT_read_enum() already has const string parameters. It fixes a warning when using the header in C++ code: error: ISO C++11 does not allow conversion from string literal to 'char *' [-Werror,-Wwritable-strings] That's because string literals have type char[N] in C and const char[N] in C++. Signed-off-by: Kuba Piecuch Signed-off-by: Tejun Heo

tools/sched_ext: Remove redundant SCX_ENQ_IMMED compat definition

2026-03-26T20:07:42Z

compat.bpf.h defined a fallback SCX_ENQ_IMMED macro using __COMPAT_ENUM_OR_ZERO(). After 6bf36c68b0a2 ("tools/sched_ext: Regenerate autogen enum headers") added SCX_ENQ_IMMED to the autogen headers, including both triggers -Wmacro-redefined warnings. The autogen definition through const volatile __weak already resolves to 0 on older kernels, providing the same backward compatibility. Remove the now-redundant compat fallback. Fixes: 6bf36c68b0a2 ("tools/sched_ext: Regenerate autogen enum headers") Link: https://lore.kernel.org/r/20260326100313.338388-1-zhaomzhao@126.com Reported-by: Zhao Mengmeng Signed-off-by: Tejun Heo

tools/sched_ext: Regenerate autogen enum headers

2026-03-25T15:58:08Z

Regenerate enum_defs.autogen.h, enums.autogen.h and enums.autogen.bpf.h using the upstream scripts [1][2] to sync with recent kernel enum additions. [1] https://github.com/sched-ext/scx/blob/main/scripts/gen_enum_defs.py [2] https://github.com/sched-ext/scx/blob/main/scripts/gen_enums.py Signed-off-by: Cheng-Yang Chou Signed-off-by: Tejun Heo

tools/sched_ext: Add scx_bpf_sub_dispatch() compat wrapper

2026-03-23T17:45:08Z

Add a transparent compatibility wrapper for the scx_bpf_sub_dispatch() kfunc in compat.bpf.h. This allows BPF schedulers using the sub-sched dispatch feature to build and run on older kernels that lack the kfunc. To avoid requiring code changes in individual schedulers, the transparent wrapper pattern is used instead of a __COMPAT prefix. The kfunc is declared with a ___compat suffix, while the static inline wrapper retains the original scx_bpf_sub_dispatch() name. When the kfunc is unavailable, the wrapper safely falls back to returning false. This is acceptable because the dispatch path cannot do anything useful without underlying sub-sched support anyway. Tested scx_qmap on v6.14 successfully. Signed-off-by: Cheng-Yang Chou Signed-off-by: Tejun Heo

tools/sched_ext: Add compat handling for sub-scheduler ops

2026-03-22T20:03:05Z

Extend SCX_OPS_OPEN() with compatibility handling for ops.sub_attach() and ops.sub_detach(), allowing scx C schedulers with sub-scheduler support to run on kernels both with and without its support. Cc: Cheng-Yang Chou Fixes: ebeca1f930ea ("sched_ext: Introduce cgroup sub-sched support") Signed-off-by: Andrea Righi Reviewed-by: Cheng-Yang Chou Signed-off-by: Tejun Heo

sched_ext: Add SCX_OPS_ALWAYS_ENQ_IMMED ops flag

2026-03-13T19:43:23Z

SCX_ENQ_IMMED makes enqueue to local DSQs succeed only if the task can start running immediately. Otherwise, the task is re-enqueued through ops.enqueue(). This provides tighter control but requires specifying the flag on every insertion. Add SCX_OPS_ALWAYS_ENQ_IMMED ops flag. When set, SCX_ENQ_IMMED is automatically applied to all local DSQ enqueues including through scx_bpf_dsq_move_to_local(). scx_qmap is updated with -I option to test the feature and -F option for IMMED stress testing which forces every Nth enqueue to a busy local DSQ. v2: - Cover scx_bpf_dsq_move_to_local() path (now has enq_flags via ___v2). - scx_qmap: Remove sched_switch and cpu_release handlers (superseded by kernel-side wakeup_preempt_scx()). Add -F for IMMED stress testing. Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi

sched_ext: Add enq_flags to scx_bpf_dsq_move_to_local()

2026-03-13T19:43:23Z

scx_bpf_dsq_move_to_local() moves a task from a non-local DSQ to the current CPU's local DSQ. This is an indirect way of dispatching to a local DSQ and should support enq_flags like direct dispatches do - e.g. SCX_ENQ_HEAD for head-of-queue insertion and SCX_ENQ_IMMED for immediate execution guarantees. Add scx_bpf_dsq_move_to_local___v2() with an enq_flags parameter. The original becomes a v1 compat wrapper passing 0. The compat macro is updated to a three-level chain: v2 (7.1+) -> v1 (current) -> scx_bpf_consume (pre-rename). All in-tree BPF schedulers are updated to pass 0. Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi

sched_ext: Implement SCX_ENQ_IMMED

2026-03-13T19:43:22Z

Add SCX_ENQ_IMMED enqueue flag for local DSQ insertions. Once a task is dispatched with IMMED, it either gets on the CPU immediately and stays on it, or gets reenqueued back to the BPF scheduler. It will never linger on a local DSQ behind other tasks or on a CPU taken by a higher-priority class. rq_is_open() uses rq->next_class to determine whether the rq is available, and wakeup_preempt_scx() triggers reenqueue when a higher-priority class task arrives. These capture all higher class preemptions. Combined with reenqueue points in the dispatch path, all cases where an IMMED task would not execute immediately are covered. SCX_TASK_IMMED persists in p->scx.flags until the next fresh enqueue, so the guarantee survives SAVE/RESTORE cycles. If preempted while running, put_prev_task_scx() reenqueues through ops.enqueue() with SCX_TASK_REENQ_PREEMPTED instead of silently placing the task back on the local DSQ. This enables tighter scheduling latency control by preventing tasks from piling up on local DSQs. It also enables opportunistic CPU sharing across sub-schedulers - without this, a sub-scheduler can stuff the local DSQ of a shared CPU, making it difficult for others to use. v2: - Rewrite is_curr_done() as rq_is_open() using rq->next_class and implement wakeup_preempt_scx() to achieve complete coverage of all cases where IMMED tasks could get stranded. - Track IMMED persistently in p->scx.flags and reenqueue preempted-while-running tasks through ops.enqueue(). - Bound deferred reenq cycles (SCX_REENQ_LOCAL_MAX_REPEAT). - Misc renames, documentation. Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi

sched_ext: remove SCX_OPS_HAS_CGROUP_WEIGHT

2026-03-09T19:45:18Z

While running scx_flatcg, dmesg prints "SCX_OPS_HAS_CGROUP_WEIGHT is deprecated and a noop", in code, SCX_OPS_HAS_CGROUP_WEIGHT has been marked as DEPRECATED, and will be removed on 6.18. Now it's time to do it. Signed-off-by: Zhao Mengmeng Signed-off-by: Tejun Heo