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    SubjectRe: [00/15] swiotlb cleanup
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    On Jul 13, 2009, at 10:13 PM, Becky Bruce wrote:

    >
    > On Jul 10, 2009, at 12:12 AM, Ingo Molnar wrote:
    >
    >>
    >> * FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:
    >>
    >>> - removes unused (and unnecessary) hooks in swiotlb.
    >>>
    >>> - adds dma_capable() and converts swiotlb to use it. It can be
    >>> used to
    >>> know if a memory area is dma capable or not. I added
    >>> is_buffer_dma_capable() for the same purpose long ago but it turned
    >>> out that the function doesn't work on POWERPC.
    >>>
    >>> This can be applied cleanly to linux-next, -mm, and mainline. This
    >>> patchset touches multiple architectures (ia64, powerpc, x86) so I
    >>> guess that -mm is appropriate for this patchset (I don't care much
    >>> what tree would merge this though).
    >>>
    >>> This is tested on x86 but only compile tested on POWERPC and IA64.
    >>>
    >>> Thanks,
    >>>
    >>> =
    >>> arch/ia64/include/asm/dma-mapping.h | 18 ++++++
    >>> arch/powerpc/include/asm/dma-mapping.h | 23 +++++++
    >>> arch/powerpc/kernel/dma-swiotlb.c | 48 +---------------
    >>> arch/x86/include/asm/dma-mapping.h | 18 ++++++
    >>> arch/x86/kernel/pci-dma.c | 2 +-
    >>> arch/x86/kernel/pci-gart_64.c | 5 +-
    >>> arch/x86/kernel/pci-nommu.c | 2 +-
    >>> arch/x86/kernel/pci-swiotlb.c | 25 --------
    >>> include/linux/dma-mapping.h | 5 --
    >>> include/linux/swiotlb.h | 11 ----
    >>> lib/swiotlb.c | 102 ++++++++
    >>> +-----------------------
    >>> 11 files changed, 92 insertions(+), 167 deletions(-)
    >>
    >> Hm, the functions and facilities you remove here were added as part
    >> of preparatory patches for Xen guest support. You were aware of
    >> them, you were involved in discussions about those aspects with Ian
    >> and Jeremy but still you chose not to Cc: either of them and you
    >> failed to address that aspect in the changelogs.
    >>
    >> I'd like the Xen code to become cleaner more than anyone else here i
    >> guess, but patch submission methods like this are not really
    >> helpful. A far better method is to be open about such disagreements,
    >> to declare them, to Cc: everyone who disagrees, and to line out the
    >> arguments in the changelogs as well - instead of just curtly
    >> declaring those APIs 'unused' and failing to Cc: involved parties.
    >>
    >> Alas, on the technical level the cleanups themselves look mostly
    >> fine to me. Ian, Jeremy, the changes will alter Xen's use of
    >> swiotlb, but can the Xen side still live with these new methods - in
    >> particular is dma_capable() sufficient as a mechanism and can the
    >> Xen side filter out DMA allocations to make them physically
    >> continuous?
    >>
    >> Ben, Tony, Becky, any objections wrt. the PowerPC / IA64 impact? If
    >> everyone agrees i can apply them to the IOMMU tree, test it and push
    >> it out to -next, etc.
    >>
    >
    > Ingo,
    >
    > With the exception of the patch I commented on, I think these look
    > OK from the powerpc point of view. I've successfully booted one of
    > my test platforms with the entire series applied and will run some
    > more extensive (i.e. not "Whee! A prompt!") tests tomorrow.

    Well, I am still testing. I've observed one unexpected LTP testcase
    failure with these patches applied, but so far have been unable to
    reproduce it. So these patches are probably OK, but I will look into
    this some more next week.

    -Becky

    >
    >
    > -Becky
    >
    > _______________________________________________
    > Linuxppc-dev mailing list
    > Linuxppc-dev@lists.ozlabs.org
    > https://lists.ozlabs.org/listinfo/linuxppc-dev



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