[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/3] cpuidle: If disable_cpuidle() is called, set pm_idle to default_idle.
On Tue, Nov 08, 2011 at 04:15:12PM -0500, Konrad Rzeszutek Wilk wrote: > . however we ignore the disable_cpuidle() directive and > in select_idle_routine() set it to type preferred by the CPU. > > This is a regression introduced by > > commit a0bfa1373859e9d11dc92561a8667588803e42d8 > Author: Len Brown <len.brown@xxxxxxxxx> > Date: Fri Apr 1 19:34:59 2011 -0400 > > cpuidle: stop depending on pm_idle > > specifically this patch: > > commit d91ee5863b71e8c90eaf6035bff3078a85e2e7b5 > Author: Len Brown <len.brown@xxxxxxxxx> > Date: Fri Apr 1 18:28:35 2011 -0400 > > cpuidle: replace xen access to x86 pm_idle and default_idle > > ..scribble on pm_idle and access default_idle, > have it simply disable_cpuidle() so acpi_idle will not load and > architecture default HLT will be used. > > .. but the default HLT does not get used. Instead we end up in the > situation that select_idle_routine() is called from > arch/x86/kernel/cpu/common.c > and if we called cpuidle_disable(), then the pm_idle is not set, and > we end up setting pm_idle to mwait_idle or amd_e400_idle. > > This patch uses the cpuidle_disabled() functionality and > makes select_idle_routine() adhere to that. > > Reported-by: Stefan Bader <stefan.bader@xxxxxxxxxxxxx> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> And just found that there is a BZ for this as well: https://bugzilla.redhat.com/show_bug.cgi?id=739499 And this patch fixes the Linux kernel to boot under Amazon EC2. Another option which I played with today was to do this instead: diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 46d6d21..45136f2 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -448,6 +448,6 @@ void __init xen_arch_setup(void) #endif disable_cpuidle(); boot_option_idle_override = IDLE_HALT; - + pm_idle = default_idle; fiddle_vdso(); } But that defeats the whole purpose of the patch series that Len developed where we would _not_ scribble on the pm_idle. <sigh> Thoughts? > > CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > CC: Ingo Molnar <mingo@xxxxxxxxxx> > CC: "H. Peter Anvin" <hpa@xxxxxxxxx> > CC: x86@xxxxxxxxxx > CC: Len Brown <len.brown@xxxxxxxxx> > CC: Borislav Petkov <bp@xxxxxxxxx> > CC: Tejun Heo <tj@xxxxxxxxxx> > CC: Thomas Renninger <trenn@xxxxxxx> > CC: stable@xxxxxxxxxx > --- > arch/x86/kernel/process.c | 5 +++++ > include/linux/cpuidle.h | 2 ++ > 2 files changed, 7 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c > index e7e3b01..1f7f8c8 100644 > --- a/arch/x86/kernel/process.c > +++ b/arch/x86/kernel/process.c > @@ -14,6 +14,7 @@ > #include <linux/utsname.h> > #include <trace/events/power.h> > #include <linux/hw_breakpoint.h> > +#include <linux/cpuidle.h> > #include <asm/cpu.h> > #include <asm/system.h> > #include <asm/apic.h> > @@ -587,6 +588,10 @@ void __cpuinit select_idle_routine(const struct > cpuinfo_x86 *c) > if (pm_idle) > return; > > + if (cpuidle_disabled()) { > + pm_idle = default_idle; > + return; > + } > if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) { > /* > * One CPU supports mwait => All CPUs supports mwait > diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h > index b51629e..123fe9e 100644 > --- a/include/linux/cpuidle.h > +++ b/include/linux/cpuidle.h > @@ -122,6 +122,7 @@ struct cpuidle_driver { > }; > > #ifdef CONFIG_CPU_IDLE > +extern int cpuidle_disabled(void); > extern void disable_cpuidle(void); > extern int cpuidle_idle_call(void); > > @@ -137,6 +138,7 @@ extern int cpuidle_enable_device(struct cpuidle_device > *dev); > extern void cpuidle_disable_device(struct cpuidle_device *dev); > > #else > +static inline int cpuidle_disabled(void) { return 1; } > static inline void disable_cpuidle(void) { } > static inline int cpuidle_idle_call(void) { return -ENODEV; } > > -- > 1.7.7.1 > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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