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Re: [Xen-devel] [For Xen-4.10 PATCH v2 3/3] Avoid excess icache flushes in populate_physmap() before domain has been created

>>> On 26.05.17 at 13:14, <punit.agrawal@xxxxxxx> wrote:
> populate_physmap() calls alloc_heap_pages() per requested
> extent. alloc_heap_pages() invalidates the entire icache per
> extent. During domain creation, the icache invalidations can be deffered
> until all the extents have been allocated as there is no risk of
> executing stale instructions from the icache.
> Introduce a new flag "MEMF_no_icache_flush" to be used to prevent
> alloc_heap_pages() from performing icache maintenance operations. Use
> the flag in populate_physmap() before the domain has been unpaused and
> perform required icache maintenance function at the end of the
> allocation.
> One concern is the lack of synchronisation around testing for
> "creation_finished". But it seems, in practice the window where it is
> out of sync should be small enough to not matter.
> Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx>
> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>

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