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Date: Thu, 25 Nov 2010 18:55:59 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: Ingo Molnar <mingo@...e.hu>
Cc: Lin Ming <ming.m.lin@...el.com>,
Stephane Eranian <eranian@...gle.com>,
"robert.richter" <robert.richter@....com>,
Corey Ashford <cjashfor@...ux.vnet.ibm.com>,
fweisbec <fweisbec@...il.com>, paulus <paulus@...ba.org>,
Greg Kroah-Hartman <gregkh@...e.de>,
Kay Sievers <kay.sievers@...y.org>,
"H. Peter Anvin" <hpa@...or.com>,
Kyle Moffett <kyle@...fetthome.net>,
linux-kernel@...r.kernel.org, davem <davem@...emloft.net>,
Michael Cree <mcree@...on.net.nz>,
Deng-Cheng Zhu <dengcheng.zhu@...il.com>,
Will Deacon <will.deacon@....com>,
Paul Mundt <lethal@...ux-sh.org>,
Don Zickus <dzickus@...hat.com>,
Jason Wessel <jason.wessel@...driver.com>
Subject: Re: [RFC][PATCH 2/8] perf, arch: Use early_initcall() for all arch
pmu implementations
On Thu, 2010-11-25 at 11:25 +0100, Peter Zijlstra wrote:
>
> Right, so hw perf init happens from (after this patch):
>
> arch_initcall: powerpc, arm, sh, mips
> early_initcall: x86, sparc, alpha
>
>
> Now the problem is that the generic watchdog code (kernel/watchdog.c)
> tries to create hw perf events, and that too runs from early_initcall.
>
> So my question is, how do we go about curing this, because powerpc, arm,
> sh and mips are too late and the rest depends on link order to work, not
> really a nice situation.
>
> There's two categories of solutions:
> - move the watchdog later, and
> - move the hw perf init earlier.
>
> The former is undesired because we want the watchdog as early as
> possible, the later needs new infrastructure (also, I don't know if the
> arch implementations can actually run this early).
>
> So do I create a perf_initcall() or is there another solution that
> avoids things like calling the watchdog code from all arch init code?
So the perf_event_init() site is _waaay_ to early to init stuff.. I
guess I'll move it all to early_initcall() and I'll move the watchdog to
an explicit call right after it.
Something like the below,.. now I guess the question to all of you is,
can your arch pmu code cope with early_initcall() or does it need to be
some other place?
---
arch/alpha/include/asm/perf_event.h | 6 ------
arch/alpha/kernel/irq_alpha.c | 2 --
arch/alpha/kernel/perf_event.c | 9 ++++++---
arch/arm/kernel/perf_event.c | 2 +-
arch/mips/kernel/perf_event_mipsxx.c | 2 +-
arch/powerpc/kernel/e500-pmu.c | 2 +-
arch/powerpc/kernel/mpc7450-pmu.c | 2 +-
arch/powerpc/kernel/power4-pmu.c | 2 +-
arch/powerpc/kernel/power5+-pmu.c | 2 +-
arch/powerpc/kernel/power5-pmu.c | 2 +-
arch/powerpc/kernel/power6-pmu.c | 2 +-
arch/powerpc/kernel/power7-pmu.c | 2 +-
arch/powerpc/kernel/ppc970-pmu.c | 2 +-
arch/sh/kernel/cpu/sh4/perf_event.c | 2 +-
arch/sh/kernel/cpu/sh4a/perf_event.c | 2 +-
arch/sparc/include/asm/perf_event.h | 4 ----
arch/sparc/kernel/nmi.c | 2 --
arch/sparc/kernel/perf_event.c | 7 +++++--
arch/x86/include/asm/perf_event.h | 2 --
arch/x86/kernel/cpu/common.c | 1 -
arch/x86/kernel/cpu/perf_event.c | 11 +++++++----
include/linux/sched.h | 4 ++++
init/main.c | 1 +
kernel/watchdog.c | 7 +++----
24 files changed, 38 insertions(+), 42 deletions(-)
Index: linux-2.6/include/linux/sched.h
===================================================================
--- linux-2.6.orig/include/linux/sched.h
+++ linux-2.6/include/linux/sched.h
@@ -316,6 +316,7 @@ extern int proc_dowatchdog_thresh(struct
size_t *lenp, loff_t *ppos);
extern unsigned int softlockup_panic;
extern int softlockup_thresh;
+void lockup_detector_init(void);
#else
static inline void touch_softlockup_watchdog(void)
{
@@ -326,6 +327,9 @@ static inline void touch_softlockup_watc
static inline void touch_all_softlockup_watchdogs(void)
{
}
+static inline void lockup_detector_init(void)
+{
+}
#endif
#ifdef CONFIG_DETECT_HUNG_TASK
Index: linux-2.6/init/main.c
===================================================================
--- linux-2.6.orig/init/main.c
+++ linux-2.6/init/main.c
@@ -884,6 +884,7 @@ static int __init kernel_init(void * unu
smp_prepare_cpus(setup_max_cpus);
do_pre_smp_initcalls();
+ lockup_detector_init();
smp_init();
sched_init_smp();
Index: linux-2.6/kernel/watchdog.c
===================================================================
--- linux-2.6.orig/kernel/watchdog.c
+++ linux-2.6/kernel/watchdog.c
@@ -547,13 +547,13 @@ static struct notifier_block __cpuinitda
.notifier_call = cpu_callback
};
-static int __init spawn_watchdog_task(void)
+void __init lockup_detector_init(void)
{
void *cpu = (void *)(long)smp_processor_id();
int err;
if (no_watchdog)
- return 0;
+ return;
err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
WARN_ON(notifier_to_errno(err));
@@ -561,6 +561,5 @@ static int __init spawn_watchdog_task(vo
cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
register_cpu_notifier(&cpu_nfb);
- return 0;
+ return;
}
-early_initcall(spawn_watchdog_task);
Index: linux-2.6/arch/alpha/include/asm/perf_event.h
===================================================================
--- linux-2.6.orig/arch/alpha/include/asm/perf_event.h
+++ linux-2.6/arch/alpha/include/asm/perf_event.h
@@ -1,10 +1,4 @@
#ifndef __ASM_ALPHA_PERF_EVENT_H
#define __ASM_ALPHA_PERF_EVENT_H
-#ifdef CONFIG_PERF_EVENTS
-extern void init_hw_perf_events(void);
-#else
-static inline void init_hw_perf_events(void) { }
-#endif
-
#endif /* __ASM_ALPHA_PERF_EVENT_H */
Index: linux-2.6/arch/alpha/kernel/irq_alpha.c
===================================================================
--- linux-2.6.orig/arch/alpha/kernel/irq_alpha.c
+++ linux-2.6/arch/alpha/kernel/irq_alpha.c
@@ -112,8 +112,6 @@ init_IRQ(void)
wrent(entInt, 0);
alpha_mv.init_irq();
-
- init_hw_perf_events();
}
/*
Index: linux-2.6/arch/alpha/kernel/perf_event.c
===================================================================
--- linux-2.6.orig/arch/alpha/kernel/perf_event.c
+++ linux-2.6/arch/alpha/kernel/perf_event.c
@@ -14,6 +14,7 @@
#include <linux/kernel.h>
#include <linux/kdebug.h>
#include <linux/mutex.h>
+#include <linux/init.h>
#include <asm/hwrpb.h>
#include <asm/atomic.h>
@@ -863,13 +864,13 @@ static void alpha_perf_event_irq_handler
/*
* Init call to initialise performance events at kernel startup.
*/
-void __init init_hw_perf_events(void)
+int __init init_hw_perf_events(void)
{
pr_info("Performance events: ");
if (!supported_cpu()) {
pr_cont("No support for your CPU.\n");
- return;
+ return 0;
}
pr_cont("Supported CPU type!\n");
@@ -882,5 +883,7 @@ void __init init_hw_perf_events(void)
alpha_pmu = &ev67_pmu;
perf_pmu_register(&pmu);
-}
+ return 0;
+}
+early_initcall(init_hw_perf_events);
Index: linux-2.6/arch/arm/kernel/perf_event.c
===================================================================
--- linux-2.6.orig/arch/arm/kernel/perf_event.c
+++ linux-2.6/arch/arm/kernel/perf_event.c
@@ -3038,7 +3038,7 @@ init_hw_perf_events(void)
return 0;
}
-arch_initcall(init_hw_perf_events);
+early_initcall(init_hw_perf_events);
/*
* Callchain handling code.
Index: linux-2.6/arch/mips/kernel/perf_event_mipsxx.c
===================================================================
--- linux-2.6.orig/arch/mips/kernel/perf_event_mipsxx.c
+++ linux-2.6/arch/mips/kernel/perf_event_mipsxx.c
@@ -1047,6 +1047,6 @@ init_hw_perf_events(void)
return 0;
}
-arch_initcall(init_hw_perf_events);
+early_initcall(init_hw_perf_events);
#endif /* defined(CONFIG_CPU_MIPS32)... */
Index: linux-2.6/arch/powerpc/kernel/e500-pmu.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/e500-pmu.c
+++ linux-2.6/arch/powerpc/kernel/e500-pmu.c
@@ -126,4 +126,4 @@ static int init_e500_pmu(void)
return register_fsl_emb_pmu(&e500_pmu);
}
-arch_initcall(init_e500_pmu);
+early_initcall(init_e500_pmu);
Index: linux-2.6/arch/powerpc/kernel/mpc7450-pmu.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/mpc7450-pmu.c
+++ linux-2.6/arch/powerpc/kernel/mpc7450-pmu.c
@@ -414,4 +414,4 @@ static int init_mpc7450_pmu(void)
return register_power_pmu(&mpc7450_pmu);
}
-arch_initcall(init_mpc7450_pmu);
+early_initcall(init_mpc7450_pmu);
Index: linux-2.6/arch/powerpc/kernel/power4-pmu.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/power4-pmu.c
+++ linux-2.6/arch/powerpc/kernel/power4-pmu.c
@@ -613,4 +613,4 @@ static int init_power4_pmu(void)
return register_power_pmu(&power4_pmu);
}
-arch_initcall(init_power4_pmu);
+early_initcall(init_power4_pmu);
Index: linux-2.6/arch/powerpc/kernel/power5+-pmu.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/power5+-pmu.c
+++ linux-2.6/arch/powerpc/kernel/power5+-pmu.c
@@ -682,4 +682,4 @@ static int init_power5p_pmu(void)
return register_power_pmu(&power5p_pmu);
}
-arch_initcall(init_power5p_pmu);
+early_initcall(init_power5p_pmu);
Index: linux-2.6/arch/powerpc/kernel/power5-pmu.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/power5-pmu.c
+++ linux-2.6/arch/powerpc/kernel/power5-pmu.c
@@ -621,4 +621,4 @@ static int init_power5_pmu(void)
return register_power_pmu(&power5_pmu);
}
-arch_initcall(init_power5_pmu);
+early_initcall(init_power5_pmu);
Index: linux-2.6/arch/powerpc/kernel/power6-pmu.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/power6-pmu.c
+++ linux-2.6/arch/powerpc/kernel/power6-pmu.c
@@ -544,4 +544,4 @@ static int init_power6_pmu(void)
return register_power_pmu(&power6_pmu);
}
-arch_initcall(init_power6_pmu);
+early_initcall(init_power6_pmu);
Index: linux-2.6/arch/powerpc/kernel/power7-pmu.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/power7-pmu.c
+++ linux-2.6/arch/powerpc/kernel/power7-pmu.c
@@ -369,4 +369,4 @@ static int init_power7_pmu(void)
return register_power_pmu(&power7_pmu);
}
-arch_initcall(init_power7_pmu);
+early_initcall(init_power7_pmu);
Index: linux-2.6/arch/powerpc/kernel/ppc970-pmu.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/ppc970-pmu.c
+++ linux-2.6/arch/powerpc/kernel/ppc970-pmu.c
@@ -494,4 +494,4 @@ static int init_ppc970_pmu(void)
return register_power_pmu(&ppc970_pmu);
}
-arch_initcall(init_ppc970_pmu);
+early_initcall(init_ppc970_pmu);
Index: linux-2.6/arch/sh/kernel/cpu/sh4/perf_event.c
===================================================================
--- linux-2.6.orig/arch/sh/kernel/cpu/sh4/perf_event.c
+++ linux-2.6/arch/sh/kernel/cpu/sh4/perf_event.c
@@ -250,4 +250,4 @@ static int __init sh7750_pmu_init(void)
return register_sh_pmu(&sh7750_pmu);
}
-arch_initcall(sh7750_pmu_init);
+early_initcall(sh7750_pmu_init);
Index: linux-2.6/arch/sh/kernel/cpu/sh4a/perf_event.c
===================================================================
--- linux-2.6.orig/arch/sh/kernel/cpu/sh4a/perf_event.c
+++ linux-2.6/arch/sh/kernel/cpu/sh4a/perf_event.c
@@ -284,4 +284,4 @@ static int __init sh4a_pmu_init(void)
return register_sh_pmu(&sh4a_pmu);
}
-arch_initcall(sh4a_pmu_init);
+early_initcall(sh4a_pmu_init);
Index: linux-2.6/arch/sparc/include/asm/perf_event.h
===================================================================
--- linux-2.6.orig/arch/sparc/include/asm/perf_event.h
+++ linux-2.6/arch/sparc/include/asm/perf_event.h
@@ -4,8 +4,6 @@
#ifdef CONFIG_PERF_EVENTS
#include <asm/ptrace.h>
-extern void init_hw_perf_events(void);
-
#define perf_arch_fetch_caller_regs(regs, ip) \
do { \
unsigned long _pstate, _asi, _pil, _i7, _fp; \
@@ -26,8 +24,6 @@ do { \
(regs)->u_regs[UREG_I6] = _fp; \
(regs)->u_regs[UREG_I7] = _i7; \
} while (0)
-#else
-static inline void init_hw_perf_events(void) { }
#endif
#endif
Index: linux-2.6/arch/sparc/kernel/nmi.c
===================================================================
--- linux-2.6.orig/arch/sparc/kernel/nmi.c
+++ linux-2.6/arch/sparc/kernel/nmi.c
@@ -270,8 +270,6 @@ int __init nmi_init(void)
atomic_set(&nmi_active, -1);
}
}
- if (!err)
- init_hw_perf_events();
return err;
}
Index: linux-2.6/arch/sparc/kernel/perf_event.c
===================================================================
--- linux-2.6.orig/arch/sparc/kernel/perf_event.c
+++ linux-2.6/arch/sparc/kernel/perf_event.c
@@ -1307,20 +1307,23 @@ static bool __init supported_pmu(void)
return false;
}
-void __init init_hw_perf_events(void)
+int __init init_hw_perf_events(void)
{
pr_info("Performance events: ");
if (!supported_pmu()) {
pr_cont("No support for PMU type '%s'\n", sparc_pmu_type);
- return;
+ return 0;
}
pr_cont("Supported PMU type is '%s'\n", sparc_pmu_type);
perf_pmu_register(&pmu);
register_die_notifier(&perf_event_nmi_notifier);
+
+ return 0;
}
+early_initcall(init_hw_perf_event);
void perf_callchain_kernel(struct perf_callchain_entry *entry,
struct pt_regs *regs)
Index: linux-2.6/arch/x86/include/asm/perf_event.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/perf_event.h
+++ linux-2.6/arch/x86/include/asm/perf_event.h
@@ -125,7 +125,6 @@ union cpuid10_edx {
#define IBS_OP_MAX_CNT_EXT 0x007FFFFFULL /* not a register bit mask */
#ifdef CONFIG_PERF_EVENTS
-extern void init_hw_perf_events(void);
extern void perf_events_lapic_init(void);
#define PERF_EVENT_INDEX_OFFSET 0
@@ -156,7 +155,6 @@ extern unsigned long perf_misc_flags(str
}
#else
-static inline void init_hw_perf_events(void) { }
static inline void perf_events_lapic_init(void) { }
#endif
Index: linux-2.6/arch/x86/kernel/cpu/common.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/common.c
+++ linux-2.6/arch/x86/kernel/cpu/common.c
@@ -894,7 +894,6 @@ void __init identify_boot_cpu(void)
#else
vgetcpu_set_mode();
#endif
- init_hw_perf_events();
}
void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -1423,7 +1423,7 @@ static void __init pmu_check_apic(void)
pr_info("no hardware sampling interrupt available.\n");
}
-void __init init_hw_perf_events(void)
+int __init init_hw_perf_events(void)
{
struct event_constraint *c;
int err;
@@ -1438,11 +1438,11 @@ void __init init_hw_perf_events(void)
err = amd_pmu_init();
break;
default:
- return;
+ return 0;
}
if (err != 0) {
pr_cont("no PMU driver, software events only.\n");
- return;
+ return 0;
}
pmu_check_apic();
@@ -1450,7 +1450,7 @@ void __init init_hw_perf_events(void)
/* sanity check that the hardware exists or is emulated */
if (!check_hw_exists()) {
pr_cont("Broken PMU hardware detected, software events only.\n");
- return;
+ return 0;
}
pr_cont("%s PMU driver.\n", x86_pmu.name);
@@ -1501,7 +1501,10 @@ void __init init_hw_perf_events(void)
perf_pmu_register(&pmu);
perf_cpu_notifier(x86_pmu_notifier);
+
+ return 0;
}
+early_initcall(init_hw_perf_events);
static inline void x86_pmu_read(struct perf_event *event)
{
--
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