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Commit 27415a4f authored by Hiroshi Shimamoto's avatar Hiroshi Shimamoto Committed by Ingo Molnar
Browse files

x86: move warning message of polling idle and HT enabled 



The warning message at idle_setup() is never shown because
smp_num_sibling hasn't been updated at this point yet.

Move this polling idle and HT enabled warning to select_idle_routine().
I also implement this warning on 64-bit kernel.

Signed-off-by: default avatarHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 2274c33e

arch/x86/kernel/process_32.c

+12 −6
Original line number Diff line number Diff line
@@ -295,17 +295,27 @@ static int mwait_usable(const struct cpuinfo_x86 *c) 


void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)

{

	static int selected;



	if (selected)

		return;

#ifdef CONFIG_X86_SMP

	if (pm_idle == poll_idle && smp_num_siblings > 1) {

		printk(KERN_WARNING "WARNING: polling idle and HT enabled,"

			" performance may degrade.\n");

	}

#endif

	if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {

		printk("monitor/mwait feature present.\n");

		/*

		 * Skip, if setup has overridden idle.

		 * One CPU supports mwait => All CPUs supports mwait

		 */

		if (!pm_idle) {

			printk("using mwait in idle threads.\n");

			printk(KERN_INFO "using mwait in idle threads.\n");

			pm_idle = mwait_idle;

		}

	}

	selected = 1;

}



static int __init idle_setup(char *str)
@@ -313,10 +323,6 @@ static int __init idle_setup(char *str) 
	if (!strcmp(str, "poll")) {

		printk("using polling idle threads.\n");

		pm_idle = poll_idle;

#ifdef CONFIG_X86_SMP

		if (smp_num_siblings > 1)

			printk("WARNING: polling idle and HT enabled, performance may degrade.\n");

#endif

	} else if (!strcmp(str, "mwait"))

		force_mwait = 1;

	else

arch/x86/kernel/process_64.c

+12 −5
Original line number Diff line number Diff line
@@ -291,20 +291,27 @@ static int mwait_usable(const struct cpuinfo_x86 *c) 


void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)

{

	static int printed;

	static int selected;



	if (selected)

		return;

#ifdef CONFIG_X86_SMP

	if (pm_idle == poll_idle && smp_num_siblings > 1) {

		printk(KERN_WARNING "WARNING: polling idle and HT enabled,"

			" performance may degrade.\n");

	}

#endif

	if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {

		/*

		 * Skip, if setup has overridden idle.

		 * One CPU supports mwait => All CPUs supports mwait

		 */

		if (!pm_idle) {

			if (!printed) {

			printk(KERN_INFO "using mwait in idle threads.\n");

				printed = 1;

			}

			pm_idle = mwait_idle;

		}

	}

	selected = 1;

}



static int __init idle_setup(char *str)