[PATCH] Add a build option to freeze the number of arenas to 1

[Mike Hommey]

On Thu, Feb 23, 2012 at 02:40:41PM +0100, Justin Lebar wrote:
> > Mozilla does not currently make extensive use of concurrent allocation,
> > so the increased fragmentation associated with multiple arenas is not
> > warranted.
> 
> If any testing was done on Firefox with its fork of jemalloc to reach
> this conclusion, surely it's no longer valid.
> 
> I'd rather stick closer to the stock implementation until we can
> demonstrate that changes are beneficial.

I really don't think Firefox will benefit from having as much arenas as
there are CPUs, and each thread being bound to a given arena. I'm pretty
certain this will significantly increase its memory footprint.

I also don't think things changed significantly with multiple arenas
between the old jemalloc fork it uses and current jemalloc.

Anyways, besides Mozilla, I'm pretty sure this can have some other uses.

Mike