Re: [Xen-devel] [PATCH] (resent) NUMA node migration

tgh
Sat, 22 Dec 2007 09:42:01 -0000

hi
for PV, is there a fast checkpoint mechanism available ? how does it
work , that is ,what paremeters in the common line"xm migration ",or
how
to invoke it? and how does it work ,say ,fast checkpoint for PV in an
incremental way such as live migration, or how to fast checkpoint ?

Thanks in advance


Ian Pratt 写道:
>
> Doing page migration for HVM guests is easy as you can just stop the
> guest, copy a bunch of pages and update the p2m table, flush the shadow
> page table cache and all VCPU''s TLBs, then resume. Doing it live
is a
> little tricky as you have to go from MFN''s to PTE''s which
currently
> requires a full shadow page table scan. [Though some of the experimental
> page sharing patches maintain linked lists of backpointers, and we could
> switch to a shadow mode that supports this while doing page migration]
>
> PV guests are a little more challenging as all references in the
> direct-mode page tables need to be updated. We also need to make sure
> that the guest isn''t holding MFNs outside of pagetables, so we
need to
> get all the VCPUs into a known state. The best way of handling this is
> to use the PV fast checkpoint support to freeze the guest, copy the
>

> badly located pages, scan and update all pagetables, resume from
> checkpoint. This would make a nice little project for someone...
>
> Ian
>
>
>
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