Review request for 5049299 (original) (raw)

Andrew Haley aph at redhat.com
Fri May 29 10:54:37 UTC 2009

Florian Weimer wrote:

* 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.overcommitmemory 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.overcommitmemory=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.

I am very sorry, "-Xmx" was a typo, or perhaps a thinko. In my original posting -- which was trimmed -- I said

It makes more sense to allocate all the -Xms size immediately.

and I thought you were disagreeing with me, but:

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

you weren't.

Andrew.

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