From: Jack F Vogel <jfv@bluesong.net>
A bug against an xSeries system showed up recently noting that the
check_nmi_watchdog() test was failing.
I have been investigating it and discovered in both i386 and x86_64 the
recent change to the routine to use the cpu_callin_map has uncovered a
problem. Prior to that change, on an SMP box, the test was trivally
passing because all cpu's were found to not yet be online, but now with the
callin_map they are discovered, it goes on to test the counter and they
have not yet begun to increment, so it announces a CPU is stuck and bails
out.
On all the systems I have access to test, the announcement of failure is
also bougs... by the time you can login and check /proc/interrupts, the
NMI count is happily incrementing on all CPUs. Its just that the test is
being done too early.
I have tried moving the call to the test around a bit, and it was always
too early. I finally hit on this proposed solution, it delays the routine
via a late_initcall(), seems like the right solution to me.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/i386/kernel/apic.c | 2 --
25-akpm/arch/i386/kernel/io_apic.c | 2 --
25-akpm/arch/i386/kernel/nmi.c | 11 +++++++----
25-akpm/arch/i386/kernel/smpboot.c | 3 ---
25-akpm/arch/x86_64/kernel/io_apic.c | 2 --
25-akpm/arch/x86_64/kernel/nmi.c | 9 +++++++--
25-akpm/include/asm-i386/apic.h | 1 -
7 files changed, 14 insertions(+), 16 deletions(-)
diff -puN arch/i386/kernel/apic.c~rfc-check-nmi-watchdog-is-broken arch/i386/kernel/apic.c
--- 25/arch/i386/kernel/apic.c~rfc-check-nmi-watchdog-is-broken 2005-03-30 18:28:21.000000000 -0800
+++ 25-akpm/arch/i386/kernel/apic.c 2005-03-30 18:28:21.000000000 -0800
@@ -1265,8 +1265,6 @@ int __init APIC_init_uniprocessor (void)
setup_local_APIC();
- if (nmi_watchdog == NMI_LOCAL_APIC)
- check_nmi_watchdog();
#ifdef CONFIG_X86_IO_APIC
if (smp_found_config)
if (!skip_ioapic_setup && nr_ioapics)
diff -puN arch/i386/kernel/io_apic.c~rfc-check-nmi-watchdog-is-broken arch/i386/kernel/io_apic.c
--- 25/arch/i386/kernel/io_apic.c~rfc-check-nmi-watchdog-is-broken 2005-03-30 18:28:21.000000000 -0800
+++ 25-akpm/arch/i386/kernel/io_apic.c 2005-03-30 18:28:21.000000000 -0800
@@ -2175,7 +2175,6 @@ static inline void check_timer(void)
disable_8259A_irq(0);
setup_nmi();
enable_8259A_irq(0);
- check_nmi_watchdog();
}
return;
}
@@ -2198,7 +2197,6 @@ static inline void check_timer(void)
add_pin_to_irq(0, 0, pin2);
if (nmi_watchdog == NMI_IO_APIC) {
setup_nmi();
- check_nmi_watchdog();
}
return;
}
diff -puN arch/i386/kernel/nmi.c~rfc-check-nmi-watchdog-is-broken arch/i386/kernel/nmi.c
--- 25/arch/i386/kernel/nmi.c~rfc-check-nmi-watchdog-is-broken 2005-03-30 18:28:21.000000000 -0800
+++ 25-akpm/arch/i386/kernel/nmi.c 2005-03-30 18:28:21.000000000 -0800
@@ -102,20 +102,21 @@ int nmi_active;
(P4_CCCR_OVF_PMI0|P4_CCCR_THRESHOLD(15)|P4_CCCR_COMPLEMENT| \
P4_CCCR_COMPARE|P4_CCCR_REQUIRED|P4_CCCR_ESCR_SELECT(4)|P4_CCCR_ENABLE)
-int __init check_nmi_watchdog (void)
+static int __init check_nmi_watchdog(void)
{
unsigned int prev_nmi_count[NR_CPUS];
int cpu;
- printk(KERN_INFO "testing NMI watchdog ... ");
+ if (nmi_watchdog == NMI_NONE)
+ return 0;
+
+ printk(KERN_INFO "Testing NMI watchdog ... ");
for (cpu = 0; cpu < NR_CPUS; cpu++)
prev_nmi_count[cpu] = per_cpu(irq_stat, cpu).__nmi_count;
local_irq_enable();
mdelay((10*1000)/nmi_hz); // wait 10 ticks
- /* FIXME: Only boot CPU is online at this stage. Check CPUs
- as they come up. */
for (cpu = 0; cpu < NR_CPUS; cpu++) {
#ifdef CONFIG_SMP
/* Check cpu_callin_map here because that is set
@@ -139,6 +140,8 @@ int __init check_nmi_watchdog (void)
return 0;
}
+/* This needs to happen later in boot so counters are working */
+late_initcall(check_nmi_watchdog);
static int __init setup_nmi_watchdog(char *str)
{
diff -puN arch/i386/kernel/smpboot.c~rfc-check-nmi-watchdog-is-broken arch/i386/kernel/smpboot.c
--- 25/arch/i386/kernel/smpboot.c~rfc-check-nmi-watchdog-is-broken 2005-03-30 18:28:21.000000000 -0800
+++ 25-akpm/arch/i386/kernel/smpboot.c 2005-03-30 18:28:21.000000000 -0800
@@ -1062,9 +1062,6 @@ static void __init smp_boot_cpus(unsigne
printk(KERN_WARNING "WARNING: %d siblings found for CPU%d, should be %d\n", siblings, cpu, smp_num_siblings);
}
- if (nmi_watchdog == NMI_LOCAL_APIC)
- check_nmi_watchdog();
-
smpboot_setup_io_apic();
setup_boot_APIC_clock();
diff -puN arch/x86_64/kernel/io_apic.c~rfc-check-nmi-watchdog-is-broken arch/x86_64/kernel/io_apic.c
--- 25/arch/x86_64/kernel/io_apic.c~rfc-check-nmi-watchdog-is-broken 2005-03-30 18:28:21.000000000 -0800
+++ 25-akpm/arch/x86_64/kernel/io_apic.c 2005-03-30 18:28:21.000000000 -0800
@@ -1607,7 +1607,6 @@ static inline void check_timer(void)
disable_8259A_irq(0);
setup_nmi();
enable_8259A_irq(0);
- check_nmi_watchdog();
}
return;
}
@@ -1627,7 +1626,6 @@ static inline void check_timer(void)
nmi_watchdog_default();
if (nmi_watchdog == NMI_IO_APIC) {
setup_nmi();
- check_nmi_watchdog();
}
return;
}
diff -puN arch/x86_64/kernel/nmi.c~rfc-check-nmi-watchdog-is-broken arch/x86_64/kernel/nmi.c
--- 25/arch/x86_64/kernel/nmi.c~rfc-check-nmi-watchdog-is-broken 2005-03-30 18:28:21.000000000 -0800
+++ 25-akpm/arch/x86_64/kernel/nmi.c 2005-03-30 18:28:21.000000000 -0800
@@ -112,17 +112,20 @@ static __init int cpu_has_lapic(void)
}
}
-int __init check_nmi_watchdog (void)
+static int __init check_nmi_watchdog (void)
{
int counts[NR_CPUS];
int cpu;
+ if (nmi_watchdog == NMI_NONE)
+ return 0;
+
if (nmi_watchdog == NMI_LOCAL_APIC && !cpu_has_lapic()) {
nmi_watchdog = NMI_NONE;
return -1;
}
- printk(KERN_INFO "testing NMI watchdog ... ");
+ printk(KERN_INFO "Testing NMI watchdog ... ");
for (cpu = 0; cpu < NR_CPUS; cpu++)
counts[cpu] = cpu_pda[cpu].__nmi_count;
@@ -154,6 +157,8 @@ int __init check_nmi_watchdog (void)
return 0;
}
+/* Have this called later during boot so counters are updating */
+late_initcall(check_nmi_watchdog);
int __init setup_nmi_watchdog(char *str)
{
diff -puN include/asm-i386/apic.h~rfc-check-nmi-watchdog-is-broken include/asm-i386/apic.h
--- 25/include/asm-i386/apic.h~rfc-check-nmi-watchdog-is-broken 2005-03-30 18:29:19.000000000 -0800
+++ 25-akpm/include/asm-i386/apic.h 2005-03-30 18:29:25.000000000 -0800
@@ -109,7 +109,6 @@ extern int APIC_init_uniprocessor (void)
extern void disable_APIC_timer(void);
extern void enable_APIC_timer(void);
-extern int check_nmi_watchdog (void);
extern void enable_NMI_through_LVT0 (void * dummy);
extern unsigned int nmi_watchdog;
_