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    SubjectRe: [PATCH 1/5] x86: Change size of node ids from u8 to u16 fixup
    David Rientjes wrote:
    > On Fri, 18 Jan 2008, Yinghai Lu wrote:
    >
    >>> +#if MAX_NUMNODES > 256
    >>> +typedef u16 numanode_t;
    >>> +#else
    >>> +typedef u8 numanode_t;
    >>> +#endif
    >>> +
    >>> #endif /* _LINUX_NUMA_H */
    >> that is wrong, you can not change pxm_to_node_map from int to u8 or u16.
    >>

    Thanks for finding this!

    >
    > Yeah, NID_INVAL is negative so no unsigned type will work here,
    > unfortunately. And that reduces the intended savings of your change since
    > the smaller type can only be used with a smaller CONFIG_NODES_SHIFT.
    >

    Excuse my ignorance but why wouldn't this work:

    static numanode_t pxm_to_node_map[MAX_PXM_DOMAINS]
    = { [0 ... MAX_PXM_DOMAINS - 1] = NUMA_NO_NODE };
    ...
    >> int acpi_map_pxm_to_node(int pxm)
    >> {
    > int node = pxm_to_node_map[pxm];
    >
    > if (node < 0)

    numanode_t node = pxm_to_node_map[pxm];

    if (node != NUMA_NO_NODE) {
    >> if (nodes_weight(nodes_found_map) >= MAX_NUMNODES)
    >> return NID_INVAL;
    >> node = first_unset_node(nodes_found_map);
    >> __acpi_map_pxm_to_node(pxm, node);
    >> node_set(node, nodes_found_map);
    >> }

    or change:
    #define NID_INVAL (-1)
    to
    #define NID_INVAL ((numanode_t)(-1))
    ...
    if (node != NID_INVAL) {
    >> if (nodes_weight(nodes_found_map) >= MAX_NUMNODES)
    >> return NID_INVAL;
    >> node = first_unset_node(nodes_found_map);
    >> __acpi_map_pxm_to_node(pxm, node);
    >> node_set(node, nodes_found_map);
    >> }

    Though why there two "node invalid" values I'm not sure... ?

    >>
    >> return node;
    >> }

    And btw, shouldn't the pxm value be sized to numanode_t size as well?
    Will it ever be larger than the largest node id?

    Thanks,
    Mike


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