• Zachary Amsden's avatar
    [PATCH] vmi: timer fixes round two · 7507ba34
    Zachary Amsden authored
    Critical bugfixes for the VMI-Timer code.
    
    1) Do not setup a one shot alarm if we are keeping the periodic alarm
       armed.  Additionally, since the periodic alarm can be run at a lower rate
       than HZ, let's fixup the guard to the no-idle-hz mode appropriately.  This
       fixes the bug where the no-idle-hz mode might have a higher interrupt rate
       than the non-idle case.
    
    2) The interrupt handler can no longer adjust xtime due to nested lock
       acquisition.  Drop this.  We don't need to check for wallclock time at
       every tick, it can be done in userspace instead.
    
    3) Add a bypass to disable noidle operation.  This is useful as a last
       minute workaround, or testing measure.
    
    4) The code to skip the IO_APIC timer testing (no_timer_check) should be
       conditional on IO_APIC, not SMP, since UP kernels can have this configured
       in as well.
    Signed-off-by: default avatarDan Hecht <dhecht@vmware.com>
    Signed-off-by: default avatarZachary Amsden <zach@vmware.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    7507ba34
vmitime.c 14.3 KB