Running with vm.overcommit_memory=2

Tyler Larson fedora-devel at
Sat Feb 19 06:50:39 UTC 2005

Luciano Miguel Ferreira Rocha wrote:
>>How much memory does it take to clone() a bash?
> $ ps -o size,vsz,rss,args 
> 1428 6244 2212 -bash
> About 1428MB, I guess. Not that it would be consumed, but that the
> kernel must guarantee to be available.
> Regards,
> Luciano Rocha

Erm.. Perhaps I'm a bit behind on things, but I though the SZ field 
shows the number of pages that a process is using, not the number of 
Megs guaranteed. That'd make your estimate just a few orders of 
magnitude high.

The VSZ will give your answer in bytes rather than pages. That's the 
total process size in virtual memory, displayed in KB. The RSS is the 
amount of that's actually IN memory. The discrepency between these 
numbers would then indicate, at least in a crude way, the difference 
between what the app thinks it's using versus what the OS actually has 
tied up in the process.

So, you're looking at something more along the lines of 6MB, rather than 
1.4GB; with 2M actually used.

Someone care to check my math?

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