• Michael Holzheu's avatar
    s390/numa: add emulation support · c29a7baf
    Michael Holzheu authored
    NUMA emulation (aka fake NUMA) distributes the available memory to nodes
    without using real topology information about the physical memory of the
    machine.
    
    Splitting the system memory into nodes replicates the memory management
    structures for each node. Particularly each node has its own "mm locks"
    and its own "kswapd" task.
    
    For large systems, under certain conditions, this results in improved
    system performance and/or latency based on reduced pressure on the mm
    locks and the kswapd tasks.
    
    NUMA emulation distributes CPUs to nodes while respecting the original
    machine topology information. This is done by trying to avoid to separate
    CPUs which reside on the same book or even on the same MC. Because the
    current Linux scheduler code requires a stable cpu to node mapping, cores
    are pinned to nodes when the first CPU thread is set online.
    
    This patch is based on the initial implementation from Philipp Hachtmann.
    Signed-off-by: default avatarMichael Holzheu <holzheu@linux.vnet.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    c29a7baf
numa_mode.h 718 Bytes