Re: Memory overcommit

[KAMEZAWA Hiroyuki]

On Tue, 27 Oct 2009 23:17:41 -0700 (PDT)
David Rientjes <rientjes@xxxxxxxxxx> wrote:

> On Wed, 28 Oct 2009, KAMEZAWA Hiroyuki wrote:
> 
> > All kernel engineers know "than expected or not" can be never known to the kernel.
> > So, oom_adj workaround is used now. (by some special users.)
> > OOM Killer itself is also a workaround, too.
> > "No kill" is the best thing but we know there are tend to be memory-leaker on bad
> > systems and all systems in this world are not perfect.
> > 
> 
> Right, and historically that has been addressed by considering total_vm 
> and adjusting it with oom_adj so that we can identify memory leaking tasks 
> through user-defined criteria.
> 
> > Yes, some more trustable values other than vmsize/rss/time are appriciated.
> > I wonder recent memory consumption speed can be an another key value.
> > 
> 
> Sounds very logical.
> 
> > Anyway, current bahavior of "killing X" is a bad thing.
> > We need some fixes.
> > 
> 
> You can easily protect X with OOM_DISABLE, as you know.  I don't think we 
> need any X-specific heuristics added to the kernel, it looks like the 
> special cases have already polluted badness() enough.
> 
It's _not_ special to X.

Almost all applications which uses many dynamica libraries can be affected by this,
total_vm. And, as I explained to Vedran, multi-threaded program like Java can easily
increase total_vm without using many anon_rss.
And it's the reason I hate overcommit_memory. size of VM doesn't tell anything.


Thanks,
-Kame

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/