Re: Fwd: Control page reclaim granularity

From: Zheng Liu
Date: Tue Mar 13 2012 - 04:22:54 EST


On Tue, Mar 13, 2012 at 01:38:56PM +0530, Kautuk Consul wrote:
> >
> > I agree, but that's not my point.
> >
> > All I'm saying is that we probably don't want to give normal
> > unprivileged usermode apps
> > the capability to set the mapping to AS_UNEVICTABLE as anyone can then
> > write an application
> > that hogs memory without allowing the kernel to free it through memory reclaim.

Yes, I think so. But it seems that there has some codes that are
possible to be abused. For example, as I said previously, applications
can mmap a normal data file with PROT_EXEC flag. Then this file gets a
high priority to keep in memory (commit: 8cab4754). So my point is that
we cannot control applications how to use these mechanisms. We just
provide them and let applications to choose how to use them.
:-)

Regards,
Zheng

>
> Sorry, I mean :
> "... that hogs kernel unmapped page-cache memory without allowing the
> kernel to free it through memory reclaim."
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