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    SubjectRe: [Part1 PATCH v5 16/22] x86, mm, numa: Move numa emulation handling down.
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    On Mon, Jun 17, 2013 at 11:22 PM, Yinghai Lu <yinghai@kernel.org> wrote:
    > On Mon, Jun 17, 2013 at 6:58 PM, Tejun Heo <tj@kernel.org> wrote:
    >> On Thu, Jun 13, 2013 at 09:03:03PM +0800, Tang Chen wrote:
    >>> From: Yinghai Lu <yinghai@kernel.org>
    >>>
    >>> numa_emulation() needs to allocate buffer for new numa_meminfo
    >>> and distance matrix, so execute it later in x86_numa_init().
    >>>
    >>> Also we change the behavoir:
    >>> - before this patch, if user input wrong data in command
    >>> line, it will fall back to next numa probing or disabling
    >>> numa.
    >>> - after this patch, if user input wrong data in command line,
    >>> it will stay with numa info probed from previous probing,
    >>> like ACPI SRAT or amd_numa.
    >>>
    >>> We need to call numa_check_memblks to reject wrong user inputs early
    >>> so that we can keep the original numa_meminfo not changed.
    >>
    >> So, this is another very subtle ordering you're adding without any
    >> comment and I'm not sure it even makes sense because the function can
    >> fail after that point.
    >
    > Yes, if it fail, we will stay with current numa info from firmware.
    > That looks like right behavior.
    >
    > Before this patch, it will fail to next numa way like if acpi srat + user
    > input fail, it will try to go with amd_numa then try apply user info.
    >
    >>
    >> I'm getting really doubtful about this whole approach of carefully
    >> splitting discovery and registration. It's inherently fragile like
    >> hell and the poor documentation makes it a lot worse. I'm gonna reply
    >> to the head message.
    >
    > Maybe look at the patch is not clear enough, but if looks at the final changed
    > code it would be more clear.

    update the patches from 1-15 with your review.

    git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git
    for-x86-mm

    https://git.kernel.org/cgit/linux/kernel/git/yinghai/linux-yinghai.git/log/?h=for-x86-mm

    Yinghai


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