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From: Tom Lane <[email protected]>
To: Robert Haas <[email protected]>
Cc: Daniel Gustafsson <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Cc: Rahila Syed <[email protected]>
Subject: Re: pgsql: Add function to get memory context stats for processes
Date: Wed, 23 Apr 2025 14:14:34 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <CA+Tgmob1HFe-EbDmLs-xoQQfWAj8aB_cPToW-OOfhs4mFLfizg@mail.gmail.com>
References: <[email protected]>
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	<CA+Tgmob7yyONbdv-DRRrWxQPL9AsXFxzs3OH1F6vxSc14prLFA@mail.gmail.com>
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	<CA+TgmoZgOwiF1auY+wxUBC+7GcjKqXFBf7D97sF4WL7HER4LgA@mail.gmail.com>
	<[email protected]>
	<CA+Tgmob1HFe-EbDmLs-xoQQfWAj8aB_cPToW-OOfhs4mFLfizg@mail.gmail.com>

Robert Haas <[email protected]> writes:
> My primary concern about the patch is that
> ProcessGetMemoryContextInterrupt() can be called from any
> CHECK_FOR_INTERRUPTS() and calls lots of DSA functions, including
> dsa_create() and, via PublishMemoryContext(), dsa_allocate0(). I'm
> shocked to hear that you and Andres think that's safe to do at any
> current or future CHECK_FOR_INTERRUPTS() anywhere in the code; but
> Andres seems very confident that it's fine, so perhaps I should just
> stop worrying and be happy that we have the feature.

Just for the record, it sounds quite unsafe to me too.  I could
credit it being all right to examine the process' MemoryContext data
structures, but calling dsa_create() from CFI seems really insane.
Way too many moving parts there.

			regards, tom lane






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