[Engine-devel] Fixed -Xmx could kill your JVM

[Alon Bar-Lev]

----- Original Message -----
> From: "Juan Hernandez" <jhernand at redhat.com>
> To: "Laszlo Hornyak" <lhornyak at redhat.com>
> Cc: engine-devel at ovirt.org
> Sent: Wednesday, September 12, 2012 3:57:33 PM
> Subject: Re: [Engine-devel] Fixed -Xmx could kill your JVM

<snip>

> 
> 
> Worst case we can change the defaults for ENGINE_HEAP_MIN and
> ENGINE_HEAP_MAX to get that behavior, for example:
> 
> ENGINE_HEAP_MIN=128m
> ENGINE_HEAP_MAX=1g
> 
> I am open to do that change, specially if you show me hard data
> proving
> that it is better for performance ;-) .

We are talking about virtual memory, allocation of the heap is done as reserved, so there is no real impact on the system if memory is unused. When a reserved page is actually used it is committed.

Unless there is a system with small page file, there is no real reason to use lower values in HEAP_MIN.

Alon.