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    SubjectRe: [RFC PATCH] Add /proc/<pid>/numa_vamaps for numa node information
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    On 05/03/2018 03:58 AM, Dave Hansen wrote:
    > On 05/02/2018 02:33 PM, Andrew Morton wrote:
    >> On Tue, 1 May 2018 22:58:06 -0700 Prakash Sangappa <prakash.sangappa@oracle.com> wrote:
    >>> For analysis purpose it is useful to have numa node information
    >>> corresponding mapped address ranges of the process. Currently
    >>> /proc/<pid>/numa_maps provides list of numa nodes from where pages are
    >>> allocated per VMA of the process. This is not useful if an user needs to
    >>> determine which numa node the mapped pages are allocated from for a
    >>> particular address range. It would have helped if the numa node information
    >>> presented in /proc/<pid>/numa_maps was broken down by VA ranges showing the
    >>> exact numa node from where the pages have been allocated.
    >
    > I'm finding myself a little lost in figuring out what this does. Today,
    > numa_maps might us that a 3-page VMA has 1 page from Node 0 and 2 pages
    > from Node 1. We group *entirely* by VMA:
    >
    > 1000-4000 N0=1 N1=2
    >
    > We don't want that. We want to tell exactly where each node's memory is
    > despite if they are in the same VMA, like this:
    >
    > 1000-2000 N1=1
    > 2000-3000 N0=1
    > 3000-4000 N1=1

    I am kind of wondering on a big memory system how many lines of output
    we might have for a large (consuming lets say 80 % of system RAM) VMA
    in interleave policy. Is not that a problem ?

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