• Len Brown's avatar
    x86 idle: remove mwait_idle() and "idle=mwait" cmdline param · 69fb3676
    Len Brown authored
    mwait_idle() is a C1-only idle loop intended to be more efficient
    than HLT, starting on Pentium-4 HT-enabled processors.
    
    But mwait_idle() has been replaced by the more general
    mwait_idle_with_hints(), which handles both C1 and deeper C-states.
    ACPI processor_idle and intel_idle use only mwait_idle_with_hints(),
    and no longer use mwait_idle().
    
    Here we simplify the x86 native idle code by removing mwait_idle(),
    and the "idle=mwait" bootparam used to invoke it.
    
    Since Linux 3.0 there has been a boot-time warning when "idle=mwait"
    was invoked saying it would be removed in 2012.  This removal
    was also noted in the (now removed:-) feature-removal-schedule.txt.
    
    After this change, kernels configured with
    (CONFIG_ACPI=n && CONFIG_INTEL_IDLE=n) when run on hardware
    that supports MWAIT will simply use HLT.  If MWAIT is desired
    on those systems, cpuidle and the cpuidle drivers above
    can be enabled.
    Signed-off-by: default avatarLen Brown <len.brown@intel.com>
    Cc: x86@kernel.org
    69fb3676
smpboot.c 35.3 KB