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    SubjectRe: [Xen-devel] Re: [Revert] Re: [PATCH] mm: sync vmalloc address space page tables in alloc_vm_area()
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    On 02/09/2011 08:22, "Ian Campbell" <Ian.Campbell@citrix.com> wrote:

    > On Thu, 2011-09-01 at 21:37 +0100, Jeremy Fitzhardinge wrote:
    >> On 09/01/2011 09:11 AM, Konrad Rzeszutek Wilk wrote:
    >>> On Thu, Sep 01, 2011 at 12:51:03PM +0100, David Vrabel wrote:
    >>>> From: David Vrabel <david.vrabel@citrix.com>
    >>> Andrew,
    >>>
    >>> I was wondering if you would be Ok with this patch for 3.1.
    >>>
    >>> It is a revert (I can prepare a proper revert if you would like
    >>> that instead of this patch).
    >>>
    >>> The users of this particular function (alloc_vm_area) are just
    >>> Xen. There are no others.
    >>
    >> I'd prefer to put explicit vmalloc_sync_all()s in the callsites where
    >> necessary, and ultimately try to work out ways of avoiding it altogether
    >> (like have some hypercall wrapper which touches the arg memory to make
    >> sure its mapped?).
    >
    > That only syncs the current pagetable though. If that is sufficient (and
    > it could well be) then perhaps just doing a vmalloc_sync_one on the
    > current page tables directly would be better than faulting to do it?

    It's probably sufficient unless the kernel has non-voluntary preemption, and
    we are not preempt_disable()d.

    -- Keir

    > It's the sort of thing you could hide inside the gnttab_set_map_op type
    > helpers I guess?
    >
    > Ian.
    >
    >
    >
    > _______________________________________________
    > Xen-devel mailing list
    > Xen-devel@lists.xensource.com
    > http://lists.xensource.com/xen-devel




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