Re: [ANNOUNCE] 3.0.1-rt11

From: Mike Galbraith
Date: Sat Aug 13 2011 - 07:49:16 EST


On Sat, 2011-08-13 at 12:53 +0200, Peter Zijlstra wrote:
> Whee, I can skip release announcements too!
>
> So no the subject ain't no mistake its not, 3.0.1-rt11 is there for the
> grabs.
>
> Changes include (including the missing -rt10):
>
> - hrtimer fix that should make RT_GROUP work again
> - RCU fixes that should make the RCU stalls go away

Oh goodie, I was just looking at some of those.

coverdale:/abuild/mike/linux-3.0-rt/:[1]# wget http://www.kernel.org/pub/linux/kernel/projects/rt/patches-3.0.1-rt11.tar.bz2
--2011-08-13 13:38:13-- http://www.kernel.org/pub/linux/kernel/projects/rt/patches-3.0.1-rt11.tar.bz2
Resolving www.kernel.org... 130.239.17.5, 199.6.1.165, 2001:6b0:e:4017:1994:313:1:0, ...
Connecting to www.kernel.org|130.239.17.5|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2011-08-13 13:38:13 ERROR 404: Not Found.

Aw poo. Darn mirrors.

This (not-signed-off-by, etc) patchlet gets -rt9 booting gripe free on
UV100 box. Well, gripe free unless you turn on spinlock debugging that
is. I haven't found where uvhub_lock and queue_lock are initialized.

[ 24.640574] BUG: spinlock bad magic on CPU#29, init/235
[ 24.640580] lock: ffff8813ffc0b008, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[ 24.640587] Pid: 235, comm: init Not tainted 3.0.1-rt9 #3


---
arch/x86/include/asm/uv/uv_bau.h | 10 +++++-----
arch/x86/kernel/apic/x2apic_uv_x.c | 6 +++---
arch/x86/platform/uv/tlb_uv.c | 2 +-
arch/x86/platform/uv/uv_time.c | 21 +++++++++++++--------
4 files changed, 22 insertions(+), 17 deletions(-)

Index: linux-3.0-rt/arch/x86/include/asm/uv/uv_bau.h
===================================================================
--- linux-3.0-rt.orig/arch/x86/include/asm/uv/uv_bau.h
+++ linux-3.0-rt/arch/x86/include/asm/uv/uv_bau.h
@@ -508,7 +508,7 @@ struct bau_control {
unsigned short uvhub_quiesce;
short socket_acknowledge_count[DEST_Q_SIZE];
cycles_t send_message;
- spinlock_t uvhub_lock;
+ raw_spinlock_t uvhub_lock;
spinlock_t queue_lock;
/* tunables */
int max_concurr;
@@ -664,15 +664,15 @@ static inline int atom_asr(short i, stru
* to be lowered below the current 'v'. atomic_add_unless can only stop
* on equal.
*/
-static inline int atomic_inc_unless_ge(spinlock_t *lock, atomic_t *v, int u)
+static inline int atomic_inc_unless_ge(raw_spinlock_t *lock, atomic_t *v, int u)
{
- spin_lock(lock);
+ raw_spin_lock(lock);
if (atomic_read(v) >= u) {
- spin_unlock(lock);
+ raw_spin_unlock(lock);
return 0;
}
atomic_inc(v);
- spin_unlock(lock);
+ raw_spin_unlock(lock);
return 1;
}

Index: linux-3.0-rt/arch/x86/platform/uv/tlb_uv.c
===================================================================
--- linux-3.0-rt.orig/arch/x86/platform/uv/tlb_uv.c
+++ linux-3.0-rt/arch/x86/platform/uv/tlb_uv.c
@@ -712,7 +712,7 @@ static void record_send_stats(cycles_t t
*/
static void uv1_throttle(struct bau_control *hmaster, struct ptc_stats *stat)
{
- spinlock_t *lock = &hmaster->uvhub_lock;
+ raw_spinlock_t *lock = &hmaster->uvhub_lock;
atomic_t *v;

v = &hmaster->active_descriptor_count;
Index: linux-3.0-rt/arch/x86/platform/uv/uv_time.c
===================================================================
--- linux-3.0-rt.orig/arch/x86/platform/uv/uv_time.c
+++ linux-3.0-rt/arch/x86/platform/uv/uv_time.c
@@ -58,7 +58,7 @@ static DEFINE_PER_CPU(struct clock_event

/* There is one of these allocated per node */
struct uv_rtc_timer_head {
- spinlock_t lock;
+ raw_spinlock_t lock;
/* next cpu waiting for timer, local node relative: */
int next_cpu;
/* number of cpus on this node: */
@@ -178,7 +178,7 @@ static __init int uv_rtc_allocate_timers
uv_rtc_deallocate_timers();
return -ENOMEM;
}
- spin_lock_init(&head->lock);
+ raw_spin_lock_init(&head->lock);
head->ncpus = uv_blade_nr_possible_cpus(bid);
head->next_cpu = -1;
blade_info[bid] = head;
@@ -232,7 +232,7 @@ static int uv_rtc_set_timer(int cpu, u64
unsigned long flags;
int next_cpu;

- spin_lock_irqsave(&head->lock, flags);
+ raw_spin_lock_irqsave(&head->lock, flags);

next_cpu = head->next_cpu;
*t = expires;
@@ -244,12 +244,12 @@ static int uv_rtc_set_timer(int cpu, u64
if (uv_setup_intr(cpu, expires)) {
*t = ULLONG_MAX;
uv_rtc_find_next_timer(head, pnode);
- spin_unlock_irqrestore(&head->lock, flags);
+ raw_spin_unlock_irqrestore(&head->lock, flags);
return -ETIME;
}
}

- spin_unlock_irqrestore(&head->lock, flags);
+ raw_spin_unlock_irqrestore(&head->lock, flags);
return 0;
}

@@ -268,7 +268,7 @@ static int uv_rtc_unset_timer(int cpu, i
unsigned long flags;
int rc = 0;

- spin_lock_irqsave(&head->lock, flags);
+ raw_spin_lock_irqsave(&head->lock, flags);

if ((head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t) || force)
rc = 1;
@@ -280,7 +280,7 @@ static int uv_rtc_unset_timer(int cpu, i
uv_rtc_find_next_timer(head, pnode);
}

- spin_unlock_irqrestore(&head->lock, flags);
+ raw_spin_unlock_irqrestore(&head->lock, flags);

return rc;
}
@@ -300,13 +300,18 @@ static int uv_rtc_unset_timer(int cpu, i
static cycle_t uv_read_rtc(struct clocksource *cs)
{
unsigned long offset;
+ cycle_t cycles;

+ preempt_disable();
if (uv_get_min_hub_revision_id() == 1)
offset = 0;
else
offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;

- return (cycle_t)uv_read_local_mmr(UVH_RTC | offset);
+ cycles = (cycle_t)uv_read_local_mmr(UVH_RTC | offset);
+ __preempt_enable_no_resched();
+
+ return cycles;
}

/*
Index: linux-3.0-rt/arch/x86/kernel/apic/x2apic_uv_x.c
===================================================================
--- linux-3.0-rt.orig/arch/x86/kernel/apic/x2apic_uv_x.c
+++ linux-3.0-rt/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -56,7 +56,7 @@ int uv_min_hub_revision_id;
EXPORT_SYMBOL_GPL(uv_min_hub_revision_id);
unsigned int uv_apicid_hibits;
EXPORT_SYMBOL_GPL(uv_apicid_hibits);
-static DEFINE_SPINLOCK(uv_nmi_lock);
+static DEFINE_RAW_SPINLOCK(uv_nmi_lock);

static struct apic apic_x2apic_uv_x;

@@ -713,10 +713,10 @@ int uv_handle_nmi(struct notifier_block
* Use a lock so only one cpu prints at a time.
* This prevents intermixed output.
*/
- spin_lock(&uv_nmi_lock);
+ raw_spin_lock(&uv_nmi_lock);
pr_info("UV NMI stack dump cpu %u:\n", smp_processor_id());
dump_stack();
- spin_unlock(&uv_nmi_lock);
+ raw_spin_unlock(&uv_nmi_lock);

return NOTIFY_STOP;
}


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