diff options
| author | Len Brown <len.brown@intel.com> | 2011-04-01 15:46:09 -0400 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2011-05-29 03:39:17 -0400 |
| commit | 5d4c47e0195b989f284907358bd5c268a44b91c7 (patch) | |
| tree | 3a7c81ff3b3f5a5eb6199044a72c0145b58db413 | |
| parent | cdaab4a0d330f70c0e5ad8c3f7c65c2e375ea180 (diff) | |
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But mwait_idle() has been replaced by the more general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: x86@kernel.org
cc: stable@kernel.org # .39.x
Signed-off-by: Len Brown <len.brown@intel.com>
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 7 | ||||
| -rw-r--r-- | arch/x86/kernel/process.c | 1 |
2 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index f1b0eb02aa1..13f0bb3187b 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -35,6 +35,13 @@ Who: Len Brown <len.brown@intel.com> ---------------------------- +What: x86 "idle=mwait" cmdline param +When: 2012 +Why: simplify x86 idle code +Who: Len Brown <len.brown@intel.com> + +---------------------------- + What: PRISM54 When: 2.6.34 diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 84f3cdae440..8fb182956cb 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -645,6 +645,7 @@ static int __init idle_setup(char *str) boot_option_idle_override = IDLE_POLL; } else if (!strcmp(str, "mwait")) { boot_option_idle_override = IDLE_FORCE_MWAIT; + WARN_ONCE(1, "\idle=mwait\" will be removed in 2012\"\n"); } else if (!strcmp(str, "halt")) { /* * When the boot option of idle=halt is added, halt is |