* Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> it _DOESN'T_ boot ;-/ and I seem to have caught a flu that makes my
> whole body hurt like hell, so I'm not getting anything done.
i think i see where your boot problem comes from:
> +struct sched_clock_data {
> + spinlock_t lock;
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@xxxxxxx>
Date: Sat May 03 18:41:11 CEST 2008
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
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 @@ static void lock_double_clock(struct sch
struct sched_clock_data *data2)
{
if (data1 < data2) {
- spin_lock(&data1->lock);
- spin_lock_nested(&data2->lock, SINGLE_DEPTH_NESTING);
+ __raw_spin_lock(&data1->lock);
+ __raw_spin_lock(&data2->lock);
} else {
- spin_lock(&data2->lock);
- spin_lock_nested(&data1->lock, SINGLE_DEPTH_NESTING);
+ __raw_spin_lock(&data2->lock);
+ __raw_spin_lock(&data1->lock);
}
}
@@ -147,14 +153,14 @@ u64 sched_clock_cpu(int cpu)
now -= my_scd->tick_gtod;
now += scd->tick_gtod;
- spin_unlock(&my_scd->lock);
+ __raw_spin_unlock(&my_scd->lock);
} else
- spin_lock(&scd->lock);
+ __raw_spin_lock(&scd->lock);
__update_sched_clock(scd, now);
clock = scd->clock;
- spin_unlock(&scd->lock);
+ __raw_spin_unlock(&scd->lock);
return clock;
}
@@ -164,7 +170,7 @@ void sched_clock_tick(void)
struct sched_clock_data *scd = this_scd();
u64 now;
- spin_lock(&scd->lock);
+ __raw_spin_lock(&scd->lock);
now = sched_clock();
__update_sched_clock(scd, now);
/*
@@ -174,7 +180,7 @@ void sched_clock_tick(void)
*/
scd->tick_raw = now;
scd->tick_gtod = ktime_to_ns(ktime_get()); // XXX get from regular tick
- spin_unlock(&scd->lock);
+ __raw_spin_unlock(&scd->lock);
}
/*
@@ -199,10 +205,10 @@ void sched_clock_idle_wakeup_event(u64 d
* and use the PM-provided delta_ns to advance the
* rq clock:
*/
- spin_lock(&scd->lock);
+ __raw_spin_lock(&scd->lock);
scd->prev_raw = sched_clock();
scd->clock += delta_ns;
- spin_unlock(&scd->lock);
+ __raw_spin_unlock(&scd->lock);
touch_softlockup_watchdog();
}
--
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