Re: [PATCH v3 1/2] sched_ext: Add dispatch transaction API

[Tejun Heo <tj@kernel.org>]

On Sun, May 10, 2026 at 03:11:56AM +0800, Cheng-Yang Chou wrote:
> -static void scx_dsq_insert_commit(struct scx_sched *sch, struct task_struct *p,
> -				  u64 dsq_id, u64 enq_flags)
> +static void scx_dsq_insert_buf(struct scx_sched *sch, struct task_struct *p,
> +			       u64 dsq_id, u64 enq_flags, unsigned long qseq)

Please don't mix rename and functional changes in the same patch. Can we do
scx_dsq_insert_stage() instead?

> +/**
> + * scx_bpf_dsq_insert_commit - Commit a dispatch transaction
> + * @p: task_struct to insert
> + * @dsq_id: DSQ to insert into
> + * @enq_flags: SCX_ENQ_*
> + * @token: token from scx_bpf_dsq_insert_begin()
> + * @aux: implicit BPF argument
> + *
> + * Like scx_bpf_dsq_insert() with slice=0, but commits a dispatch transaction
> + * begun with scx_bpf_dsq_insert_begin(). If @p was dequeued or claimed
> + * between begin and commit, the dispatch is silently discarded. Use
> + * scx_bpf_task_set_slice() to set a non-default slice.
> + *
> + * Returns %true if the entry was buffered for dispatch, %false on preamble
> + * failure (e.g. @p is not owned by this scheduler). Note: stale token
> + * detection fires asynchronously in finish_dispatch() after ops.dispatch()
> + * returns. A %true return does not guarantee the task was actually dispatched.
> + */

I think this needs more detailed documentation. It's difficult to tell what
it provides and why one would want to use it from the above and it's a
pretty subtle thing.

Thanks.

-- 
tejun