Re: [patch] swapin rlimit

Martin J. Bligh
2005-11-04T15:24:04Z

> System instrumentation people are already complaining about how costly
> /proc parsing is. If you have to get some nontrivial stat from all
> threads in the system, and if Linux doesnt offer that counter or summary
> by default, it gets pretty expensive.
>
> One solution i can think of would be to make a binary representation of
> /proc/<pid>/stats readonly-mmap-able. This would add a 4K page to every
> task tracked that way, and stats updates would have to update this page
> too - but it would make instrumentation of running apps really
> unintrusive and scalable.

That would be awesome - the current methods we have are mostly crap. There
are some atomicity issues though. Plus when I suggested this 2 years ago,
everyone told me to piss off, but I'm not bitter ;-) Seriously, we do
need a fast communication mechanism.

M.