• Shreyas B. Prabhu's avatar
    powerpc: Fix cpu_online_cores_map to return only online threads mask · e602ffb2
    Shreyas B. Prabhu authored
    Currently, cpu_online_cores_map returns a mask, which for every core with
    at least one online thread, has the bit for thread 0 of the core set to 1,
    and the bits for all other threads of the core set to 0. But thread 0 of
    the core itself may not be online always. In such cases, if the returned
    mask is used for IPI, then it'll cause IPIs to be skipped on cores where
    the first thread is offline, because the IPI code refuses to send IPIs to
    offline threads.
    
    Fix this by setting the bit of the first online thread in the core.
    This is done by fixing this in the underlying function
    cpu_thread_mask_to_cores.
    
    The result has the property that for all cores with online threads, there
    is one bit set in the returned map. And further, all bits that are set in
    the returned map correspond to online threads.
    Signed-off-by: default avatarShreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
    Reviewed-by: default avatarPreeti U Murthy <preeti@linux.vnet.ibm.com>
    [ Changelog from Michael Ellerman <mpe@ellerman.id.au> ]
    Reviewed-by: default avatarGautham R. Shenoy <ego@linux.vnet.ibm.com>
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    e602ffb2
cputhreads.h 2.5 KB