On Sun, Dec 4, 2016 at 11:05 PM, Michal Hocko <mhocko@kernel.org> wrote:

> On Sun 04-12-16 13:56:54, Raymond Jennings wrote:
> > I have an application that is generating HUGE amounts of dirty data.
> > Multiple GiB worth, and I'd like to allow it to fill at least half of my
> > RAM.
>
> Could you be more specific why and what kind of problem you are trying
> to solve?
>
> > I already have /proc/sys/vm/dirty_ratio pegged at 80 and the background
> one
> > pegged at 50.  RAM is 32GiB.
>
> There is also dirty_bytes alternative which is an absolute numer.
>

How does this compare to setting dirty_ratio to a high percentage?

>
> > it appears to be butting heads with clean memory.  How do I tell my
> system
> > to prefer using RAM to soak up writes instead of caching?
>
> I am not sure I understand. Could you be more specific about what is the
> actual problem? Is it possible that your dirty data is already being
> flushed and that is wy you see a clean cache?
>

What I'm wanting is for my writing process not to get throttled, even when
the dirty memory it starts creating starts hogging memory the system would
rather use for cache.