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    SubjectRe: [PATCH] mm/alloc: fallback to first node if the wanted node offline
    On Tue, 4 Dec 2018, Pingfan Liu wrote:

    > diff --git a/include/linux/gfp.h b/include/linux/gfp.h
    > index 76f8db0..8324953 100644
    > --- a/include/linux/gfp.h
    > +++ b/include/linux/gfp.h
    > @@ -453,6 +453,8 @@ static inline int gfp_zonelist(gfp_t flags)
    > */
    > static inline struct zonelist *node_zonelist(int nid, gfp_t flags)
    > {
    > + if (unlikely(!node_online(nid)))
    > + nid = first_online_node;
    > return NODE_DATA(nid)->node_zonelists + gfp_zonelist(flags);
    > }
    >

    So we're passing the node id from dev_to_node() to kmalloc which
    interprets that as the preferred node and then does node_zonelist() to
    find the zonelist at allocation time.

    What happens if we fix this in alloc_dr()? Does anything else cause
    problems?

    And rather than using first_online_node, would next_online_node() work?

    I'm thinking about this:

    diff --git a/drivers/base/devres.c b/drivers/base/devres.c
    --- a/drivers/base/devres.c
    +++ b/drivers/base/devres.c
    @@ -100,6 +100,8 @@ static __always_inline struct devres * alloc_dr(dr_release_t release,
    &tot_size)))
    return NULL;

    + if (unlikely(!node_online(nid)))
    + nid = next_online_node(nid);
    dr = kmalloc_node_track_caller(tot_size, gfp, nid);
    if (unlikely(!dr))
    return NULL;
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