[FFmpeg-devel] [PATCH] NellyMoser audio decoder

[Daniel Serpell]

Hi

El Tue, Sep 11, 2007 at 08:02:32PM -0400, Rich Felker escribio:
> On Wed, Sep 12, 2007 at 01:30:22AM +0200, Michael Niedermayer wrote:
> > 
> > the argument that the kernel can find such tables quickly even if 
> > generated at runtime and share them with a copy on write hasnt been
> > brought up yet :)
> 
> I don't want a kernel process hashing and comparing pages while I'm
> trying to watch a movie to determine which ones it can combine... The
> extra bookkeeping is just a bad idea.

But you could do it only on page-out. Just hash the page before going
to disk. If the hash matches an already paged-out one, you don't have
to store it again.

And, when you page-in some page from swap, you traverse the list of
pages with that hash and bring all in, using copy-on-write.

    Daniel.