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RE: [Xen-devel] Reducing impact of save/restore/dump on Dom0

> -----Original Message-----
> From: Jeremy Fitzhardinge [mailto:jeremy@xxxxxxxx]
> Ian Pratt wrote:
> > As for making the IO bypass the buffer cache, I'm not sure what the
> best
> > way to do this is. There are some occasions where we want the
> > image to be in the buffer cache (e.g. as used by the fault injection
> > testing for fast domain restart) but I agree that its not helpful in
> the
> > normal case. My first inclination would be O_DIRECT, but there may
> a
> > better way.
> O_DIRECT is strongly deprecated.  fadvise(..., FADV_DONTNEED, ...) is
> the preferred interface.

I'm currently experimenting with using fsync/fadvise - will post results
shortly. If this works well, then it's not essential to change the
on-disk format although I think the performance will be better if it is

I do find it a little annoying that in Linux the routine is actually
called posix_fadvise64 rather than fadvise64 but I can obviously work
round that.


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