that wont work very well when sched_clock() is called from within
CONFIG_LOCK_STAT instrumentation. Does the patch below solve the boot
problems for you?
Ingo
-------------------->
Subject: sched: sched_clock() fix
From: Ingo Molnar <mingo@elte.hu>
Date: Sat May 03 18:41:11 CEST 2008
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/sched.c | 2 --
kernel/sched_clock.c | 42 ++++++++++++++++++++++++------------------
2 files changed, 24 insertions(+), 20 deletions(-)
Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -1074,8 +1074,6 @@ static struct rq *this_rq_lock(void)
return rq;
}
- WARN_ON(!irqs_disabled());
- WARN_ON(!irqs_disabled());
static void __resched_task(struct task_struct *p, int tif_bit);
static inline void resched_task(struct task_struct *p)
Index: linux/kernel/sched_clock.c
===================================================================
--- linux.orig/kernel/sched_clock.c
+++ linux/kernel/sched_clock.c
@@ -33,12 +33,18 @@
#ifndef CONFIG_HAVE_STABLE_CLOCK
struct sched_clock_data {
- spinlock_t lock;
- unsigned long prev_jiffies;
- u64 prev_raw;
- u64 tick_raw;
- u64 tick_gtod;
- u64 clock;
+ /*
+ * Raw spinlock - this is a special case: this might be called
+ * from within instrumentation code so we dont want to do any
+ * instrumentation ourselves.
+ */
+ raw_spinlock_t lock;
+
+ unsigned long prev_jiffies;
+ u64 prev_raw;
+ u64 tick_raw;
+ u64 tick_gtod;
+ u64 clock;
};
static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);
@@ -62,7 +68,7 @@ void sched_clock_init(void)
for_each_possible_cpu(cpu) {
struct sched_clock_data *scd = cpu_sdc(cpu);
- spin_lock_init(&scd->lock);
+ scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
scd->prev_jiffies = jiffies;
scd->prev_raw = now;
scd->tick_raw = now;
@@ -116,11 +122,11 @@ ...
