• Yinghai Lu's avatar
    x86, numa: Use near(er) online node instead of roundrobin for NUMA · d9c2d5ac
    Yinghai Lu authored
    CPU to node mapping is set via the following sequence:
    
     1. numa_init_array(): Set up roundrobin from cpu to online node
    
     2. init_cpu_to_node(): Set that according to apicid_to_node[]
    			according to srat only handle the node that
    			is online, and leave other cpu on node
    			without ram (aka not online) to still
    			roundrobin.
    
    3. later call srat_detect_node for Intel/AMD, will use first_online
       node or nearby node.
    
    Problem is that setup_per_cpu_areas() is not called between 2 and 3,
    the per_cpu for cpu on node with ram is on different node, and could
    put that on node with two hops away.
    
    So try to optimize this and add find_near_online_node() and call
    init_cpu_to_node().
    Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
    Cc: Tejun Heo <tj@kernel.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Rusty Russell <rusty@rustcorp.com.au>
    Cc: David Rientjes <rientjes@google.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    LKML-Reference: <4B07A739.3030104@kernel.org>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    d9c2d5ac
intel.c 13.1 KB