Re: [Xen-devel] [PATCH] tools/libxc: send page-in requests in batches in linux_privcmd_map_foreign_bulk

[Olaf Hering <olaf@xxxxxxxxx>]

On Thu, Jan 26, Andres Lagar-Cavilla wrote:

> >> Why not alloc a separate arr2 array, move the gfn's that failed with
> >> ENOENT there, and retry the whole new arr2 block? You only need to
> >> allocate arr2 once, to size num. That will batch always, everything.
> >
> > The errors for gfns are most likely fragmented. Merging the gfns means
> > they will get a different addr. So the overall layout of arr and err
> > needs to remain the same.
> 
> Ummh yeah, addr is the problem. But as you say, the error for the gfns are
> fragmented, so that seriously limits your batching abilities.
 
> You could pass the whole arr sub-segment encompassing the first and last
> gfn that failed with ENOENT. Successful maps within that array will be
> re-done by the hypervisor, at no correctness cost. I would imagine that
> the extra work is offset by the gains, but that remains to be seen.

Isnt that what the patch does, find a range of ENOENTs and try that
again?

Olaf

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