More then 2G of memory per process

Matt Domsch Matt_Domsch at
Tue Aug 5 16:33:01 CDT 2003

> I'm running an application that was developed in house. We are starting
> to exceed the limit of approximately 2 gigs of memory per application.
> Are there any options that will allow us to increase this limit?

Red Hat Enterprise Linux 3 public beta "Taroon" has a 'bigmem' kernel 
which implements a 4GB kernel / 4GB user memory split.  This increases the 
amount of address space available to user processes from 3GB to just under 
4GB, which should help a good bit.  It *really* helps the kernel, as it 
now gets 4GB of address space, up from 1GB previously.

There is a performance penalty to switching to a 4GB/4GB model from the 
current 1GB/3GB model in use today.  Each application will behave 
somewhate differently.  We'd love to hear what your performance 
differences are between running on a kernel with a 3/1 split vs. a 4/4 

> We are currently using 7.3 bigmem kernel with 4 gigs of physical ram. I'm
> planning on increasing the physical ram to 8 gigs.

There are no plans to release a 4/4 split kernel for products such as 


Matt Domsch
Sr. Software Engineer, Lead Engineer
Dell Linux Solutions
Linux on Dell mailing lists @

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