[Pan-users] Re: Feature request: CLI operation

[Duncan]

Ron Johnson posted on Tue, 29 Mar 2011 03:09:22 -0500 as excerpted:

> It's 32-bit.  Running "top" clearly shows pan's memory usage (RES)
> growing and growing.  At about 3GB (a processes' address space in x86)
> it barfs.

FWIW, on Linux that's a kernel option (with 2.6 kernels, anyway).  With 
the 4-gig limit, the kernel/userspace split can be set to 3G/1G, 2G/2G, or 
the default 1G/3G.  Additionally, there's a somewhat less efficient mode 
that sets 4G/4G, thus allowing access to (almost) a full 4-gig userspace 
(and a full 4G kernelspace, thus significantly reducing low memory 
pressure on 32G+ physical memory systems), but at the cost of switching 
memory pagetables and doing TLB flushes at every usercode/kernelcode 
switch.

So it's possible to up that ~3GB to ~4GB.  (There's a few MB worth of 
buffers of commonly mapped space between the two modes, so it's not 
/quite/ 4GB.)

Whether it's worth the additional overhead I don't know...  If you've >16G 
of physical memory, it likely is, and almost certainly is with >32G 
physical memory, due to the reduction in low-memory pressure, but under 
16G...

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman