[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] blkif discard attributes
On Thu, Jul 03, 2014 at 11:24:30AM +0100, Jan Beulich wrote: > >>> On 03.07.14 at 12:17, <david.vrabel@xxxxxxxxxx> wrote: > > On 03/07/14 11:08, Jan Beulich wrote: > >>>>> On 03.07.14 at 11:43, <david.vrabel@xxxxxxxxxx> wrote: > >>> On 03/07/14 08:59, Jan Beulich wrote: > >>>> discard_zeroes_data also be communicated from backend to frontend? > >>> > >>> Perhaps. But how would you handle a guest that used to have > >>> discard_zeroes_data but is restored with different storage that no > >>> longer has this property? > >> > >> Don't these attributes gets re-evaluated after restore anyway? > > > > I don't see how that helps. What if a discard request was submitted > > before the suspend, expecting the discard to zero and on restore the > > requests is queued for the new backend which then might not zero. > > Hmm, good point. So it's then indeed better to not communicate this. > Albeit similar issues arise with the existing attributes we communicate: > What if the new backend doesn't satisfy the assumptions on the old > one? Possibly the request may get failed, but possibly it may also get > executed wrongly. Neither of which is very desirable. That is OK with discard operations. It is OK if they fail intermediately. > > Jan > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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