Review request for 5049299
fweimer at bfk.de
Fri May 29 10:47:06 UTC 2009
* 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/
Kriegsstraße 100 tel: +49-721-96201-1
D-76133 Karlsruhe fax: +49-721-96201-99
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