sched_ext: Pack scx_ent_flags' multi-bit fields at the top

The following patches add a flag for a kernel-owned slice to scx_ent_flags.
The two 3-bit fields, the task state at bits 8 to 10 and the reenqueue
reason at bits 12 to 14, sit right above the single-bit flags, so the new
flag would have to take bit 11 or 15, out of sequence with the rest.

Pack the fields at the top of the word, below SCX_TASK_CURSOR, the state at
bits 25 to 27 and the reason at bits 28 to 30, so that the single-bit flags
continue from bit 8.

The renumbering changes the values a BPF scheduler reads from p->scx.flags.
Nothing in the kernel or the in-tree schedulers hardcodes the numbers. The
enum ABI table in tools/sched_ext/include/scx/enums_abi.autogen.h, kept for
repairing enum values that a kernel's BTF truncates, is regenerated for the
two fields. In the scx repository, scx_eevdf tests SCX_TASK_REENQ_IMMED and
SCX_TASK_REENQ_PREEMPTED against SCX_TASK_REENQ_REASON_MASK. Those three
names belong in its load-time enum table, so that they follow the running
kernel. No behavior change.

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

0 files changed, 0 insertions, 0 deletions