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    SubjectRe: [PATCH 1/2] kmemcheck v3
    Hi Christoph,

    On Thu, 7 Feb 2008, Vegard Nossum wrote:
    > > - DMA can be a problem since there's generally no way for kmemcheck to
    > > determine when/if a chunk of memory is used for DMA. Ideally, DMA should be
    > > allocated with untracked caches, but this requires annotation of the
    > > drivers in question.

    On Feb 8, 2008 9:10 AM, Christoph Lameter <clameter@sgi.com> wrote:
    > There is a fundamental misunderstanding here: GFP_DMA allocations have
    > nothing to do with DMA. Rather GFP_DMA means allocate memory in a special
    > range of physical memory that is required by legacy devices that cannot
    > use the high address bits for one or the other reason. Any regular
    > memory can be used for DMA.

    No there isn't and we've been over this with Vegard many times :-).
    Christoph, can you actually see this in the patch? There shouldn't be
    any __GFP_DMA confusion there. What we have is per-object
    __GFP_NOTRACK which can be used to suppress false positives for
    DMA-filled objects and SLAB_NOTRACK for whole _caches_ that contains
    objects which we must not take page faults at all.


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