Review request for 5049299

[Florian Weimer]

* Andrew Haley:

> Florian Weimer wrote:
>> * Andrew Haley:
>> 
>>>> The latter leads to problems if the maximum heap size is relatively large.
>>>> Currently, -Xmx is reserved, and some software fails to build on
>>>> vm.overcommit_memory systems due to this.
>>> I don't get it.  Why would overcommit cause some software to fail to
>>> build?  I can understand it failing if overcommit was turned off.
>> 
>> Sorry, I meant to write "vm.overcommit_memory=2".
>
> Well, the system is doing what the user asked it to do.  -Xmx means
> "please reserve this memory for me, Hal"; if the memory isn't there,
> then it's surely quite reasonable for Hal to respond "I'm sorry Dave,
> I can't do that."

Well, I thought -Xms means that.  An untuned VM is not expected to hit
the -Xmx limit.  At least this is what I see in practice, and to me
this is the distinction expressed between the -Xmx and -Xms flags.

Reserving the -Xms heap portion does make sense, though.

-- 
Florian Weimer                <fweimer at bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
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