Re: [v3 PATCH 2/4] powernv:smp: Add busy-wait loop as fall back for CPU-Hotplug

2017-03-30 Thread Gautham R Shenoy
On Mon, Mar 27, 2017 at 10:43:44PM +1100, Michael Ellerman wrote:
> "Gautham R. Shenoy"  writes:
> 
> > diff --git a/arch/powerpc/platforms/powernv/idle.c 
> > b/arch/powerpc/platforms/powernv/idle.c
> > index 419edff..f335e0f 100644
> > --- a/arch/powerpc/platforms/powernv/idle.c
> > +++ b/arch/powerpc/platforms/powernv/idle.c
> > @@ -283,8 +283,16 @@ unsigned long pnv_cpu_offline(unsigned int cpu)
> > } else if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
> >(idle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
> > srr1 = power7_sleep();
> > -   } else {
> > +   } else if (idle_states & OPAL_PM_NAP_ENABLED) {
> > srr1 = power7_nap(1);
> > +   } else {
> > +   /* This is the fallback method. We emulate snooze */
> > +   while (!generic_check_cpu_restart(cpu)) {
> 
> Breaks the SMP=n build :/

Hmmm.. Looks like I have missed adding a CONFIG_HOTPLUG_CPU somewhere.
> 
> arch/powerpc/platforms/powernv/idle.c:299:11: error: implicit declaration of 
> function 'generic_check_cpu_restart' [-Werror=implicit-function-declaration]
>

Could you add the following patch as the PATCH 1 in the series instead
of what was present in this series ? It adds a CONFIG_HOTPLUG_CPU
around pnv_cpu_offline(). I have compiled it with both all
combinations of CONFIG_HOTPLUG_CPU and CONFIG_SMP and it builds fine.


x-x-x---
powernv: Move CPU-Offline idle state invocation from smp.c to idle.c

Move the piece of code in powernv/smp.c::pnv_smp_cpu_kill_self() which
transitions the CPU to the deepest available platform idle state to a
new function named pnv_cpu_offline() in powernv/idle.c. The rationale
behind this code movement is that the data required to determine the
deepest available platform state resides in powernv/idle.c.

Reviewed-by: Nicholas Piggin 
Signed-off-by: Gautham R. Shenoy 
---
Restricts pnv_cpu_offline() to CONFIG_HOTPLUG_CPU

 arch/powerpc/include/asm/cpuidle.h   |  1 +
 arch/powerpc/platforms/powernv/idle.c| 27 +++
 arch/powerpc/platforms/powernv/powernv.h |  2 --
 arch/powerpc/platforms/powernv/smp.c | 18 ++
 4 files changed, 30 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/include/asm/cpuidle.h 
b/arch/powerpc/include/asm/cpuidle.h
index 1557315..4649ca0 100644
--- a/arch/powerpc/include/asm/cpuidle.h
+++ b/arch/powerpc/include/asm/cpuidle.h
@@ -46,6 +46,7 @@
 
 extern u64 pnv_first_deep_stop_state;
 
+unsigned long pnv_cpu_offline(unsigned int cpu);
 int validate_psscr_val_mask(u64 *psscr_val, u64 *psscr_mask, u32 flags);
 static inline void report_invalid_psscr_val(u64 psscr_val, int err)
 {
diff --git a/arch/powerpc/platforms/powernv/idle.c 
b/arch/powerpc/platforms/powernv/idle.c
index 4ee837e..fafafa3 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -265,6 +265,33 @@ static void power9_idle(void)
 u64 pnv_deepest_stop_psscr_val;
 u64 pnv_deepest_stop_psscr_mask;
 
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * pnv_cpu_offline: A function that puts the CPU into the deepest
+ * available platform idle state on a CPU-Offline.
+ */
+unsigned long pnv_cpu_offline(unsigned int cpu)
+{
+   unsigned long srr1;
+
+   u32 idle_states = pnv_get_supported_cpuidle_states();
+
+   if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+   srr1 = power9_idle_stop(pnv_deepest_stop_psscr_val,
+   pnv_deepest_stop_psscr_mask);
+   } else if (idle_states & OPAL_PM_WINKLE_ENABLED) {
+   srr1 = power7_winkle();
+   } else if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
+  (idle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
+   srr1 = power7_sleep();
+   } else {
+   srr1 = power7_nap(1);
+   }
+
+   return srr1;
+}
+#endif
+
 /*
  * Power ISA 3.0 idle initialization.
  *
diff --git a/arch/powerpc/platforms/powernv/powernv.h 
b/arch/powerpc/platforms/powernv/powernv.h
index 6130522..6dbc0a1 100644
--- a/arch/powerpc/platforms/powernv/powernv.h
+++ b/arch/powerpc/platforms/powernv/powernv.h
@@ -18,8 +18,6 @@ static inline void pnv_pci_shutdown(void) { }
 #endif
 
 extern u32 pnv_get_supported_cpuidle_states(void);
-extern u64 pnv_deepest_stop_psscr_val;
-extern u64 pnv_deepest_stop_psscr_mask;
 
 extern void pnv_lpc_init(void);
 
diff --git a/arch/powerpc/platforms/powernv/smp.c 
b/arch/powerpc/platforms/powernv/smp.c
index 8b67e1e..914b456 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -35,6 +35,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include "powernv.h"
 
@@ -140,7 +141,6 @@ static void pnv_smp_cpu_kill_self(void)
 {
unsigned int cpu;
unsigned long srr1, wmask;
-   u32 idle_states;
 
/* Standard hot unplug procedure */
local_irq_disable();
@@ -155,8 +155,6 @@ static void pnv_smp_cpu_kill_self(void)
if (cpu_has

Re: [v3 PATCH 2/4] powernv:smp: Add busy-wait loop as fall back for CPU-Hotplug

2017-03-27 Thread Michael Ellerman
"Gautham R. Shenoy"  writes:

> diff --git a/arch/powerpc/platforms/powernv/idle.c 
> b/arch/powerpc/platforms/powernv/idle.c
> index 419edff..f335e0f 100644
> --- a/arch/powerpc/platforms/powernv/idle.c
> +++ b/arch/powerpc/platforms/powernv/idle.c
> @@ -283,8 +283,16 @@ unsigned long pnv_cpu_offline(unsigned int cpu)
>   } else if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
>  (idle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
>   srr1 = power7_sleep();
> - } else {
> + } else if (idle_states & OPAL_PM_NAP_ENABLED) {
>   srr1 = power7_nap(1);
> + } else {
> + /* This is the fallback method. We emulate snooze */
> + while (!generic_check_cpu_restart(cpu)) {

Breaks the SMP=n build :/

arch/powerpc/platforms/powernv/idle.c:299:11: error: implicit declaration of 
function 'generic_check_cpu_restart' [-Werror=implicit-function-declaration]

cheers