sched_ext: scx_qmap: move task_ctx into a BPF arena slab

Arena simplifies verification and allows more natural programming.
Convert scx_qmap to arena as preparation for further sub-sched work.

Allocate per-task context from an arena slab instead of storing it
directly in task_storage. task_ctx_stor now holds an arena pointer to
the task's slab entry. Free entries form a singly-linked list protected
by bpf_res_spin_lock; slab exhaustion triggers scx_bpf_error().

The slab size is configurable via the new -N option (default 16384).

Also add bpf_res_spin_lock/unlock declarations to common.bpf.h.

Scheduling logic unchanged.

v2: Add task_ctx_t typedef for struct task_ctx __arena (Emil).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>

0 files changed, 0 insertions, 0 deletions