Re: pgsql: Add function to get memory context stats for processes - Mailing list pgsql-hackers

> On 17 Apr 2025, at 16:42, Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Tue, Apr 15, 2025 at 6:11 AM Andres Freund <andres@anarazel.de> wrote:
>> There very well could be a CFI - but it better be somewhere where the
>> in-memory state is consistent. Otherwise an error inside raised in the CFI
>> would lead the in-memory state inconsistent which then would cause problems
>> when cleaning up the dsa during resowner release or process exit.
>>
>> What am I missing here?
>
> I think maybe you're only thinking about gathering the data. What
> about publishing it? If the DSA code were interrupted at a CFI and the
> interrupting code went and tried to perform a DSA allocation to store
> the resulting data and then returned to the interrupted DSA operation,
> would you expect the code to cope with that? I do not believe we have
> anywhere enough guarantees about reentrancy for that to be safe.

Do you mean that an interrupt handler will make DSA allocations?  I don't think
that would be something we'd want to allow regardless of this patch.  Or did I
misunderstand the above?

--
Daniel Gustafsson