[Xen-changelog] NMI watchdog hooks off ac_timer softirq rather than apic timer irq.

[BitKeeper B. <ri...@su...>]

ChangeSet 1.1360, 2005/03/24 11:04:24+00:00, ka...@fi...

	NMI watchdog hooks off ac_timer softirq rather than apic timer irq.
	In extreme situations we may service ac_timer events without ever
	actually taking an apic interrupt.
	Signed-off-by: Keir Fraser <ke...@xe...>



 arch/x86/apic.c        |    5 -----
 arch/x86/nmi.c         |    2 +-
 common/ac_timer.c      |   17 +++++++----------
 include/asm-x86/apic.h |    5 -----
 include/xen/ac_timer.h |    8 ++++++++
 5 files changed, 16 insertions(+), 21 deletions(-)


diff -Nru a/xen/arch/x86/apic.c b/xen/arch/x86/apic.c
--- a/xen/arch/x86/apic.c	2005-03-24 07:02:49 -05:00
+++ b/xen/arch/x86/apic.c	2005-03-24 07:02:49 -05:00
@@ -722,15 +722,10 @@
     return 1;
 }
 
-unsigned int apic_timer_irqs [NR_CPUS];
-
 void smp_apic_timer_interrupt(struct xen_regs * regs)
 {
     ack_APIC_irq();
-
-    apic_timer_irqs[smp_processor_id()]++;
     perfc_incrc(apic_timer);
-
     raise_softirq(AC_TIMER_SOFTIRQ);
 }
 
diff -Nru a/xen/arch/x86/nmi.c b/xen/arch/x86/nmi.c
--- a/xen/arch/x86/nmi.c	2005-03-24 07:02:49 -05:00
+++ b/xen/arch/x86/nmi.c	2005-03-24 07:02:49 -05:00
@@ -271,7 +271,7 @@
 {
     int sum, cpu = smp_processor_id();
 
-    sum = apic_timer_irqs[cpu];
+    sum = ac_timers[cpu].softirqs;
 
     if ( (last_irq_sums[cpu] == sum) && watchdog_on )
     {
diff -Nru a/xen/common/ac_timer.c b/xen/common/ac_timer.c
--- a/xen/common/ac_timer.c	2005-03-24 07:02:49 -05:00
+++ b/xen/common/ac_timer.c	2005-03-24 07:02:49 -05:00
@@ -34,14 +34,7 @@
 
 #define DEFAULT_HEAP_LIMIT 127
 
-/* A timer list per CPU */
-typedef struct ac_timers_st
-{
-    spinlock_t        lock;
-    struct ac_timer **heap;
-} __cacheline_aligned ac_timers_t;
-static ac_timers_t ac_timers[NR_CPUS];
-
+struct ac_timers ac_timers[NR_CPUS];
 
 /****************************************************************************
  * HEAP OPERATIONS.
@@ -214,6 +207,8 @@
     s_time_t         now;
     void             (*fn)(unsigned long);
 
+    ac_timers[cpu].softirqs++;
+
     spin_lock_irq(&ac_timers[cpu].lock);
     
     do {
@@ -277,8 +272,10 @@
 
     for ( i = 0; i < smp_num_cpus; i++ )
     {
-        ac_timers[i].heap = xmalloc_array(struct ac_timer *, DEFAULT_HEAP_LIMIT+1);
-        if ( ac_timers[i].heap == NULL ) BUG();
+        ac_timers[i].heap = xmalloc_array(
+            struct ac_timer *, DEFAULT_HEAP_LIMIT+1);
+        BUG_ON(ac_timers[i].heap == NULL);
+
         SET_HEAP_SIZE(ac_timers[i].heap, 0);
         SET_HEAP_LIMIT(ac_timers[i].heap, DEFAULT_HEAP_LIMIT);
         spin_lock_init(&ac_timers[i].lock);
diff -Nru a/xen/include/asm-x86/apic.h b/xen/include/asm-x86/apic.h
--- a/xen/include/asm-x86/apic.h	2005-03-24 07:02:49 -05:00
+++ b/xen/include/asm-x86/apic.h	2005-03-24 07:02:49 -05:00
@@ -83,12 +83,7 @@
 extern void disable_APIC_timer(void);
 extern void enable_APIC_timer(void);
 
-/*extern struct pm_dev *apic_pm_register(pm_dev_t, unsigned long, pm_callback);*/
-/*extern void apic_pm_unregister(struct pm_dev*);*/
-
 extern unsigned int watchdog_on;
-
-extern unsigned int apic_timer_irqs [NR_CPUS];
 extern int check_nmi_watchdog (void);
 
 extern unsigned int nmi_watchdog;
diff -Nru a/xen/include/xen/ac_timer.h b/xen/include/xen/ac_timer.h
--- a/xen/include/xen/ac_timer.h	2005-03-24 07:02:49 -05:00
+++ b/xen/include/xen/ac_timer.h	2005-03-24 07:02:49 -05:00
@@ -19,6 +19,7 @@
 #ifndef _AC_TIMER_H_
 #define _AC_TIMER_H_
 
+#include <xen/spinlock.h>
 #include <xen/time.h>
 
 struct ac_timer {
@@ -86,6 +87,13 @@
  */
 
 extern int reprogram_ac_timer(s_time_t timeout);
+
+struct ac_timers {
+    spinlock_t        lock;
+    struct ac_timer **heap;
+    unsigned int      softirqs;
+} __cacheline_aligned;
+extern struct ac_timers ac_timers[];
 
 #endif /* _AC_TIMER_H_ */