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Message-Id: <20170330091915.GA12109@in.ibm.com>
Date: Thu, 30 Mar 2017 14:49:15 +0530
From: Gautham R Shenoy <ego@...ux.vnet.ibm.com>
To: Michael Ellerman <mpe@...erman.id.au>
Cc: "Gautham R. Shenoy" <ego@...ux.vnet.ibm.com>,
Michael Neuling <mikey@...ling.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
"Shreyas B. Prabhu" <shreyasbp@...il.com>,
Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>,
Anton Blanchard <anton@...ba.org>,
Balbir Singh <bsingharora@...il.com>,
Akshay Adiga <akshay.adiga@...ux.vnet.ibm.com>,
Nicholas Piggin <npiggin@...il.com>,
Mahesh J Salgaonkar <mahesh@...ux.vnet.ibm.com>,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [v3 PATCH 2/4] powernv:smp: Add busy-wait loop as fall back for
CPU-Hotplug
On Mon, Mar 27, 2017 at 10:43:44PM +1100, Michael Ellerman wrote:
> "Gautham R. Shenoy" <ego@...ux.vnet.ibm.com> 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 <npiggin@...il.com>
Signed-off-by: Gautham R. Shenoy <ego@...ux.vnet.ibm.com>
---
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 <asm/dbell.h>
#include <asm/kvm_ppc.h>
#include <asm/ppc-opcode.h>
+#include <asm/cpuidle.h>
#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_feature(CPU_FTR_ARCH_207S))
wmask = SRR1_WAKEMASK_P8;
- idle_states = pnv_get_supported_cpuidle_states();
-
/* We don't want to take decrementer interrupts while we are offline,
* so clear LPCR:PECE1. We keep PECE2 (and LPCR_PECE_HVEE on P9)
* enabled as to let IPIs in.
@@ -184,19 +182,7 @@ static void pnv_smp_cpu_kill_self(void)
kvmppc_set_host_ipi(cpu, 0);
ppc64_runlatch_off();
-
- 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);
- }
-
+ srr1 = pnv_cpu_offline(cpu);
ppc64_runlatch_on();
/*
--
1.9.4
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