Re: pgstat: add pgstat_prep_pending() for entry ref pending setup

On Wed, Jul 15, 2026 at 08:40:21PM -0500, Sami Imseih wrote:
> What I am saying is that in order to perform steps 1-4 with individual
> steps rather than the single pgstat_prep_pending_entry(), the API for
> step 4, to prepare the pending entry, is missing.
>
> In the common fast path case (step 1 succeeds, entry already exists), I have
> a valid entry_ref from pgstat_get_entry_ref(create=false). To attach
> pending data to it without the proposed API, I would have to call
> pgstat_prep_pending_entry(), which internally calls pgstat_get_entry_ref
> (create=true) again. That repeats all the work that was already done in
> step 1, key initialization, setup checks, the GC scan
> (pgstat_need_entry_refs_gc),
> and the local cache lookup, all to get back the same entry I already hold.
>
> pgstat_prep_pending() avoids that: it attaches pending data directly
> to the entry_ref I already have, with none of the redundant overhead.

Ah, OK. So your argument is about making even the fast path where an
entry already exists. Indeed that looks like a waste to not do a
separation. I initially thought that this was no big deal, but now I
see your point. Your change makes sense, then.
--
Michael