Re: [RFC] /dev/anon

[Jeff Dike]

On Tue, Jan 13, 2004 at 08:46:23PM -0800, Davide Libenzi wrote:
> What do you mean for throw out data? If you mean writing DONTNEED'ed 
> dirty pages to the backed up file and release them to the page cache, it 
> does. 

Writing dirty pages to backing store isn't throwing them out.

> If you mean stop handling page faults inside the DONTNEED'ed region, 
> it does not. 

This is kind of moot since the region won't be mapped anywhere, so there
can't be page faults on it.

> If you mean zero-filling (ala ftruncate()) the DONTNEED'ed 
> region, it obviously does not. 

Yes, I mean this, as a side-effect of dropping the region as though it were
clean.

> I thought your goal was to release memory 
> to the host, that's why I proposed sys_madvise(MADV_DONTNEED).

It is, I want memory released immediately as though it were clean, and
MADV_DONTNEED doesn't help.

				Jeff
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