Commit [ad010c]  Maximize  Restore  History

x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param

mwait_idle() is a C1-only idle loop intended to be more efficient
than HLT on SMP hardware that supports it.

But mwait_idle() has been replaced by the more general
mwait_idle_with_hints(), which handles both C1 and deeper C-states.
ACPI uses only mwait_idle_with_hints(), and never uses mwait_idle().

Deprecate mwait_idle() and the "idle=mwait" cmdline param
to simplify the x86 idle code.

After this change, kernels configured with
(!CONFIG_ACPI=n && !CONFIG_INTEL_IDLE=n) when run on hardware
that support MWAIT will simply use HLT. If MWAIT is desired
on those systems, cpuidle and the cpuidle drivers above
can be used.

cc: # .39.x
Signed-off-by: Len Brown <>

Len Brown Len Brown 2011-04-01

changed Documentation/feature-removal-schedule.txt
changed arch/x86/kernel/process.c
Documentation/feature-removal-schedule.txt Diff Switch to side-by-side view
arch/x86/kernel/process.c Diff Switch to side-by-side view