Re: missing madvise functionality

[Rik van Riel]

Marko Macek wrote:
> Ulrich Drepper wrote:
> > A solution for this problem is a madvise() operation with the following
> > property:
> >
> >   - the content of the address range can be discarded
> >
> >   - if an access to a page in the range happens in the future it must
> >     succeed.  The old page content can be provided or a new, empty page
> >     can be provided
>
> Doesn't this conflict with disabling overcommit?

Not really.  The threshold below which glibc does not give memory
back to the kernel at all is dynamic already.  It is entirely
possible to make an application that frees tens of thousands of
3000 byte chunks, in a pattern that makes it impossible for glibc
to return any memory to the kernel.

If you want to run without overcommit, don't run too close to the
wire :)

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