• Martin Schwidefsky's avatar
    s390/preempt: move preempt_count to the lowcore · c360192b
    Martin Schwidefsky authored
    Convert s390 to use a field in the struct lowcore for the CPU
    preemption count. It is a bit cheaper to access a lowcore field
    compared to a thread_info variable and it removes the depencency
    on a task related structure.
    
    bloat-o-meter on the vmlinux image for the default configuration
    (CONFIG_PREEMPT_NONE=y) reports a small reduction in text size:
    
    add/remove: 0/0 grow/shrink: 18/578 up/down: 228/-5448 (-5220)
    
    A larger improvement is achieved with the default configuration
    but with CONFIG_PREEMPT=y and CONFIG_DEBUG_PREEMPT=n:
    
    add/remove: 2/6 grow/shrink: 59/4477 up/down: 1618/-228762 (-227144)
    Reviewed-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    c360192b
lowcore.h 6.18 KB