Re: memory management suggestion

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Karel Zak <zakkr(at)zf(dot)jcu(dot)cz>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Jan Wieck <wieck(at)debis(dot)com>
Subject: Re: memory management suggestion
Date: 2000-06-13 00:08:15
Message-ID: 200006130008.UAA11578@candle.pha.pa.us
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Here is a followup to it.

> Karel Zak <zakkr(at)zf(dot)jcu(dot)cz> writes:
> > Create from this non-used residual space chunk and remove it into free
> > chunk list.
>
> There's at least one bug in that code: the minimum acceptable chunk size
> is not MAXALIGN(1), but 1 << ALLOC_MINBITS, and after that it goes up by
> powers of 2. You are putting the chunk into a freelist based on which
> freelist would be used to allocate a request for X amount of space...
> but it had better go into a freelist based on being large enough for the
> largest request that would be directed to that freelist, instead. As is,
> the chunk could be handed out to someone who would scribble past the
> allocated end of the block.
>
> -----> A tested patch (hmm, we are freeze, possible for 7.0.?):
>
> It's getting pretty late in the cycle for this sort of thing.
> We should consider it for 7.1, after you get it right...
>
> regards, tom lane
>

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