• Peter Zijlstra's avatar
    perf: Remove the nmi parameter from the swevent and overflow interface · a8b0ca17
    Peter Zijlstra authored
    
    
    The nmi parameter indicated if we could do wakeups from the current
    context, if not, we would set some state and self-IPI and let the
    resulting interrupt do the wakeup.
    
    For the various event classes:
    
      - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from
        the PMI-tail (ARM etc.)
      - tracepoint: nmi=0; since tracepoint could be from NMI context.
      - software: nmi=[0,1]; some, like the schedule thing cannot
        perform wakeups, and hence need 0.
    
    As one can see, there is very little nmi=1 usage, and the down-side of
    not using it is that on some platforms some software events can have a
    jiffy delay in wakeup (when arch_irq_work_raise isn't implemented).
    
    The up-side however is that we can remove the nmi parameter and save a
    bunch of conditionals in fast paths.
    Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: Michael Cree <mcree@orcon.net.nz>
    Cc: Will Deacon <will.deacon@arm.com>
    Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
    Cc: Anton Blanchard <anton@samba.org>
    Cc: Eric B Munson <emunson@mgebm.net>
    Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
    Cc: Paul Mundt <lethal@linux-sh.org>
    Cc: David S. Miller <davem@davemloft.net>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Jason Wessel <jason.wessel@windriver.com>
    Cc: Don Zickus <dzickus@redhat.com>
    Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org
    
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    a8b0ca17
fault.c 17.1 KB