Re: pg_shmem_allocations & documentation

Here's a proposal patch.

Le ven. 11 déc. 2020 à 09:58, Benoit Lobréau <benoit.lobreau@gmail.com> a
écrit :

> Would "NULL for anonymous allocations, since details related to them are
> not known." be ok ?
>
>
> Le ven. 11 déc. 2020 à 09:29, Kyotaro Horiguchi <horikyota.ntt@gmail.com>
> a écrit :
>
>> At Fri, 11 Dec 2020 14:42:45 +0900, Michael Paquier <michael@paquier.xyz>
>> wrote in
>> > On Fri, Dec 11, 2020 at 11:00:58AM +0900, Kyotaro Horiguchi wrote:
>> > > Although we could just rip some words off, I'd like to propose instead
>> > > to add an explanation why it is not exposed for anonymous allocations,
>> > > like the column allocated_size.
>> >
>> > Indeed, there is a hiccup between what the code does and what the docs
>> > tell: the offset is not NULL for unused memory.
>> >
>> > > -       The offset at which the allocation starts. NULL for anonymous
>> > > -       allocations and unused memory.
>> > > +       The offset at which the allocation starts. For anonymous
>> allocations,
>> > > +       no information about individual allocations is available, so
>> the column
>> > > +       will be NULL in that case.
>> >
>> > I'd say: let's be simple and just remove "and unused memory" because
>> > anonymous allocations are...  Anonymous so you cannot know details
>> > related to them.  That's something easy to reason about, and the docs
>> > were written originally to remain simple.
>>
>> Hmm. I don't object to that.  Howerver, isn't the description for
>> allocated_size too verbose in that sense?
>>
>> regards.
>>
>> --
>> Kyotaro Horiguchi
>> NTT Open Source Software Center
>>
>