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Date:      Mon, 28 Oct 1996 22:01:46 +0000 (GMT)
From:      Rob Hartill <robh@imdb.com>
To:        freebsd-questions@freebsd.org
Subject:   Re: server death when swap space is all gone.
Message-ID:  <199610282201.WAA10772>

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John Dyson wrote:
>
>(The "humor" in this message is not directed to the original poster, but
> perhaps is slightly misguided Linux oriented friend :-)).
>
>> 
>> On a related note, a Linux using friend takes pleasure in telling me
>> that FreeBSD is brian-dead w.r.t memory management because it can't diff
>> a couple of 20Mb files on a machine with ample memory and swap (combined).
>> 
>Didn't know that diff used mmap?  Linux is brain-dead because it doesn't
>push unused pages out to swapspace, until memory needs to be freed. :-).
>You know that it is faster to free up the memory, thereby letting the
>system utilize the ram, as opposed to tying it up with stuff that should
>be on swap? :-).  Many of the complaints are due to people not
>understanding this bit of info (or perhaps Linux fervor)...

I know linux is crap, but the simple fact is my 96Mb FreeBSD machine
with 77Mb of swap, doing nothing but "diff" on two files falls over
with "diff: memory exhausted", while a 48mb linux machine with ? swap
can produce the 700k diff file.

When I run diff, "top" shows no evidence that the swap is being used or
that 'cache' memory being reclaimed. The process grows to 33Mb then reports
"diff: memory exhausted".

I think we tried this once on a FreeBSD machine with far more swap and
it failed there too.

Why does the FreeBSD's superior memory management let me down ?


-- 
Rob Hartill (robh@imdb.com)    
http://www.imdb.com/  ... why wait for a clear night to see the stars?.



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