[Intel-gfx] [PATCH 41/46] drm/i915: Introduce concept of per-timeline (context) HWSP

[Chris Wilson]

Quoting John Harrison (2019-01-15 00:55:39)
> On 1/7/2019 03:55, Chris Wilson wrote:
> > Supplement the per-engine HWSP with a per-timeline HWSP. That is a
> > per-request pointer through which we can check a local seqno,
> > abstracting away the presumption of a global seqno. In this first step,
> > we point each request back into the engine's HWSP so everything
> > continues to work with the global timeline.
> > ---
> > +static inline u32 i915_request_hwsp(const struct i915_request *rq)
> > +{
> > +     return READ_ONCE(*rq->hwsp_seqno);
> > +}
> > +
> Shouldn't the function name have an _seqno as well? Just 
> 'i915_request_hwsp()' is fairly ambiguous, there could be many different 
> things stored in the HWSP.

It's not even necessarily the HWSP! :)

i915_request_hw_seqno() // dissatisfying
-> i915_request_hwsp_seqno() // but rq only stores one element in HWSP!
-> i915_request_hwsp()

Was the evolution of names I chose.

Of that mix, i915_request_hwsp_seqno(). hw_seqno just feels nondescript.

i915_request_current_[hw]_seqno() maybe, but because we start with
i915_request I find it confusing and expect the seqno to be tied to the
request. So maybe just drop i915_request here, and go with something
like hwsp_breadcrumb(), that just happens to take i915_request as a
convenience.
-Chris