From: Len Brown <[email protected]> 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But mwait_idle() has been replaced by the more general mwait_idle_with_hints(), which handles both C1 and deeper C-states.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 will support it. cc: [email protected] cc: [email protected] Signed-off-by: Len Brown <[email protected]> --- Documentation/feature-removal-schedule.txt | 7 +++++++ 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 f587159..9ee4a2c 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -35,6 +35,13 @@ Who: Len Brown <[email protected]> ---------------------------- +What: x86 "idle=mwait" cmdline param +When: 2.6.40 +Why: simplify x86 idle code +Who: Len Brown <[email protected]> + +---------------------------- + What: PRISM54 When: 2.6.34 diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 17b8771..1f64501 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 2.6.40\"\n"); } else if (!strcmp(str, "halt")) { /* * When the boot option of idle=halt is added, halt is -- 1.7.5.rc0 _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
