* [PATCH RT 1/8] cpu_down: move migrate_enable() back
2014-01-16 1:58 [PATCH RT 0/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
@ 2014-01-16 1:58 ` Steven Rostedt
2014-01-16 1:58 ` [PATCH RT 2/8] swait: Add a few more users Steven Rostedt
` (7 subsequent siblings)
8 siblings, 0 replies; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 1:58 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Tiejun Chen
[-- Attachment #1: 0001-cpu_down-move-migrate_enable-back.patch --]
[-- Type: text/plain, Size: 1633 bytes --]
3.2.53-rt76-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Tiejun Chen <tiejun.chen@windriver.com>
Commit 08c1ab68, "hotplug-use-migrate-disable.patch", intends to
use migrate_enable()/migrate_disable() to replace that combination
of preempt_enable() and preempt_disable(), but actually in
!CONFIG_PREEMPT_RT_FULL case, migrate_enable()/migrate_disable()
are still equal to preempt_enable()/preempt_disable(). So that
followed cpu_hotplug_begin()/cpu_unplug_begin(cpu) would go schedule()
to trigger schedule_debug() like this:
_cpu_down()
|
+ migrate_disable() = preempt_disable()
|
+ cpu_hotplug_begin() or cpu_unplug_begin()
|
+ schedule()
|
+ __schedule()
|
+ preempt_disable();
|
+ __schedule_bug() is true!
So we should move migrate_enable() as the original scheme.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/cpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 063c2bb..031c644 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -546,6 +546,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
err = -EBUSY;
goto restore_cpus;
}
+ migrate_enable();
cpu_hotplug_begin();
err = cpu_unplug_begin(cpu);
@@ -598,7 +599,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
out_release:
cpu_unplug_done(cpu);
out_cancel:
- migrate_enable();
cpu_hotplug_done();
if (!err)
cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
--
1.8.4.3
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH RT 2/8] swait: Add a few more users
2014-01-16 1:58 [PATCH RT 0/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
2014-01-16 1:58 ` [PATCH RT 1/8] cpu_down: move migrate_enable() back Steven Rostedt
@ 2014-01-16 1:58 ` Steven Rostedt
2014-01-16 1:58 ` [PATCH RT 3/8] lockdep: Correctly annotate hardirq context in irq_exit() Steven Rostedt
` (6 subsequent siblings)
8 siblings, 0 replies; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 1:58 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior, John Kacur
[-- Attachment #1: 0002-swait-Add-a-few-more-users.patch --]
[-- Type: text/plain, Size: 2651 bytes --]
3.2.53-rt76-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
The wait-simple queue is lighter weight and more efficient than the full
wait queue, and may be used in atomic context on PREEMPT_RT.
Fix up some places that needed to call the swait_*() functions instead
of the wait_*() functions.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
drivers/net/wireless/orinoco/orinoco_usb.c | 2 +-
drivers/usb/gadget/f_fs.c | 2 +-
drivers/usb/gadget/inode.c | 4 ++--
3 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/wireless/orinoco/orinoco_usb.c b/drivers/net/wireless/orinoco/orinoco_usb.c
index 0793e42..d45833f 100644
--- a/drivers/net/wireless/orinoco/orinoco_usb.c
+++ b/drivers/net/wireless/orinoco/orinoco_usb.c
@@ -714,7 +714,7 @@ static void ezusb_req_ctx_wait(struct ezusb_priv *upriv,
while (!ctx->done.done && msecs--)
udelay(1000);
} else {
- wait_event_interruptible(ctx->done.wait,
+ swait_event_interruptible(ctx->done.wait,
ctx->done.done);
}
break;
diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index 0e641a1..c6154ca 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -1270,7 +1270,7 @@ static void ffs_data_put(struct ffs_data *ffs)
BUG_ON(mutex_is_locked(&ffs->mutex) ||
spin_is_locked(&ffs->ev.waitq.lock) ||
waitqueue_active(&ffs->ev.waitq) ||
- waitqueue_active(&ffs->ep0req_completion.wait));
+ swaitqueue_active(&ffs->ep0req_completion.wait));
kfree(ffs);
}
}
diff --git a/drivers/usb/gadget/inode.c b/drivers/usb/gadget/inode.c
index 7138540..616d19e 100644
--- a/drivers/usb/gadget/inode.c
+++ b/drivers/usb/gadget/inode.c
@@ -339,7 +339,7 @@ ep_io (struct ep_data *epdata, void *buf, unsigned len)
spin_unlock_irq (&epdata->dev->lock);
if (likely (value == 0)) {
- value = wait_event_interruptible (done.wait, done.done);
+ value = swait_event_interruptible (done.wait, done.done);
if (value != 0) {
spin_lock_irq (&epdata->dev->lock);
if (likely (epdata->ep != NULL)) {
@@ -348,7 +348,7 @@ ep_io (struct ep_data *epdata, void *buf, unsigned len)
usb_ep_dequeue (epdata->ep, epdata->req);
spin_unlock_irq (&epdata->dev->lock);
- wait_event (done.wait, done.done);
+ swait_event (done.wait, done.done);
if (epdata->status == -ECONNRESET)
epdata->status = -EINTR;
} else {
--
1.8.4.3
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH RT 3/8] lockdep: Correctly annotate hardirq context in irq_exit()
2014-01-16 1:58 [PATCH RT 0/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
2014-01-16 1:58 ` [PATCH RT 1/8] cpu_down: move migrate_enable() back Steven Rostedt
2014-01-16 1:58 ` [PATCH RT 2/8] swait: Add a few more users Steven Rostedt
@ 2014-01-16 1:58 ` Steven Rostedt
2014-01-16 1:58 ` [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock Steven Rostedt
` (5 subsequent siblings)
8 siblings, 0 replies; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 1:58 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Frederic Weisbecker, Linus Torvalds, Andrew Morton,
Peter Zijlstra, Ingo Molnar
[-- Attachment #1: 0003-lockdep-Correctly-annotate-hardirq-context-in-irq_ex.patch --]
[-- Type: text/plain, Size: 4289 bytes --]
3.2.53-rt76-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Peter Zijlstra <peterz@infradead.org>
There was a reported deadlock on -rt which lockdep didn't report.
It turns out that in irq_exit() we tell lockdep that the hardirq
context ends and then do all kinds of locking afterwards.
To fix it, move trace_hardirq_exit() to the very end of irq_exit(), this
ensures all locking in tick_irq_exit() and rcu_irq_exit() are properly
recorded as happening from hardirq context.
This however leads to the 'fun' little problem of running softirqs
while in hardirq context. To cure this make the softirq code a little
more complex (in the CONFIG_TRACE_IRQFLAGS case).
Due to stack swizzling arch dependent trickery we cannot pass an
argument to __do_softirq() to tell it if it was done from hardirq
context or not; so use a side-band argument.
When we do __do_softirq() from hardirq context, 'atomically' flip to
softirq context and back, so that no locking goes without being in
either hard- or soft-irq context.
I didn't find any new problems in mainline using this patch, but it
did show the -rt problem.
Cc: stable-rt@vger.kernel.org
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-dgwc5cdksbn0jk09vbmcc9sa@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/softirq.c | 45 ++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 42 insertions(+), 3 deletions(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index ca00a68..b261fad 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -297,6 +297,44 @@ EXPORT_SYMBOL(local_bh_enable_ip);
*/
#define MAX_SOFTIRQ_RESTART 10
+#ifdef CONFIG_TRACE_IRQFLAGS
+/*
+ * Convoluted means of passing __do_softirq() a message through the various
+ * architecture execute_on_stack() bits.
+ *
+ * When we run softirqs from irq_exit() and thus on the hardirq stack we need
+ * to keep the lockdep irq context tracking as tight as possible in order to
+ * not miss-qualify lock contexts and miss possible deadlocks.
+ */
+static DEFINE_PER_CPU(int, softirq_from_hardirq);
+
+static inline void lockdep_softirq_from_hardirq(void)
+{
+ this_cpu_write(softirq_from_hardirq, 1);
+}
+
+static inline void lockdep_softirq_start(void)
+{
+ if (this_cpu_read(softirq_from_hardirq))
+ trace_hardirq_exit();
+ lockdep_softirq_enter();
+}
+
+static inline void lockdep_softirq_end(void)
+{
+ lockdep_softirq_exit();
+ if (this_cpu_read(softirq_from_hardirq)) {
+ this_cpu_write(softirq_from_hardirq, 0);
+ trace_hardirq_enter();
+ }
+}
+
+#else
+static inline void lockdep_softirq_from_hardirq(void) { }
+static inline void lockdep_softirq_start(void) { }
+static inline void lockdep_softirq_end(void) { }
+#endif
+
asmlinkage void __do_softirq(void)
{
__u32 pending;
@@ -308,7 +346,7 @@ asmlinkage void __do_softirq(void)
__local_bh_disable((unsigned long)__builtin_return_address(0),
SOFTIRQ_OFFSET);
- lockdep_softirq_enter();
+ lockdep_softirq_start();
cpu = smp_processor_id();
restart:
@@ -324,7 +362,7 @@ restart:
if (pending)
wakeup_softirqd();
- lockdep_softirq_exit();
+ lockdep_softirq_end();
account_system_vtime(current);
__local_bh_enable(SOFTIRQ_OFFSET);
@@ -583,6 +621,7 @@ static inline void invoke_softirq(void)
{
#ifndef CONFIG_PREEMPT_RT_FULL
if (!force_irqthreads)
+ lockdep_softirq_from_hardirq();
__do_softirq();
else {
__local_bh_disable((unsigned long)__builtin_return_address(0),
@@ -618,7 +657,6 @@ static inline void invoke_softirq(void)
void irq_exit(void)
{
account_system_vtime(current);
- trace_hardirq_exit();
sub_preempt_count(IRQ_EXIT_OFFSET);
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();
@@ -629,6 +667,7 @@ void irq_exit(void)
if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched())
tick_nohz_stop_sched_tick(0);
#endif
+ trace_hardirq_exit(); /* must be last! */
__preempt_enable_no_resched();
}
--
1.8.4.3
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock
2014-01-16 1:58 [PATCH RT 0/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
` (2 preceding siblings ...)
2014-01-16 1:58 ` [PATCH RT 3/8] lockdep: Correctly annotate hardirq context in irq_exit() Steven Rostedt
@ 2014-01-16 1:58 ` Steven Rostedt
2014-01-16 3:08 ` Mike Galbraith
2014-01-16 1:58 ` [PATCH RT 5/8] smp: introduce a generic on_each_cpu_mask() function Steven Rostedt
` (4 subsequent siblings)
8 siblings, 1 reply; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 1:58 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Mike Galbraith
[-- Attachment #1: 0004-rtmutex-use-a-trylock-for-waiter-lock-in-trylock.patch --]
[-- Type: text/plain, Size: 5107 bytes --]
3.2.53-rt76-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Mike Galbraith captered the following:
| >#11 [ffff88017b243e90] _raw_spin_lock at ffffffff815d2596
| >#12 [ffff88017b243e90] rt_mutex_trylock at ffffffff815d15be
| >#13 [ffff88017b243eb0] get_next_timer_interrupt at ffffffff81063b42
| >#14 [ffff88017b243f00] tick_nohz_stop_sched_tick at ffffffff810bd1fd
| >#15 [ffff88017b243f70] tick_nohz_irq_exit at ffffffff810bd7d2
| >#16 [ffff88017b243f90] irq_exit at ffffffff8105b02d
| >#17 [ffff88017b243fb0] reschedule_interrupt at ffffffff815db3dd
| >--- <IRQ stack> ---
| >#18 [ffff88017a2a9bc8] reschedule_interrupt at ffffffff815db3dd
| > [exception RIP: task_blocks_on_rt_mutex+51]
| >#19 [ffff88017a2a9ce0] rt_spin_lock_slowlock at ffffffff815d183c
| >#20 [ffff88017a2a9da0] lock_timer_base.isra.35 at ffffffff81061cbf
| >#21 [ffff88017a2a9dd0] schedule_timeout at ffffffff815cf1ce
| >#22 [ffff88017a2a9e50] rcu_gp_kthread at ffffffff810f9bbb
| >#23 [ffff88017a2a9ed0] kthread at ffffffff810796d5
| >#24 [ffff88017a2a9f50] ret_from_fork at ffffffff815da04c
lock_timer_base() does a try_lock() which deadlocks on the waiter lock
not the lock itself.
This patch takes the waiter_lock with trylock so it should work from interrupt
context as well. If the fastpath doesn't work and the waiter_lock itself is
taken then it seems that the lock itself taken.
This patch also adds a "rt_spin_try_unlock" to keep lockdep happy. If we
managed to take the wait_lock in the first place we should also be able
to take it in the unlock path.
Cc: stable-rt@vger.kernel.org
Reported-by: Mike Galbraith <bitbucket@online.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
include/linux/spinlock_rt.h | 1 +
kernel/rtmutex.c | 31 +++++++++++++++++++++++++++----
kernel/timer.c | 2 +-
3 files changed, 29 insertions(+), 5 deletions(-)
diff --git a/include/linux/spinlock_rt.h b/include/linux/spinlock_rt.h
index 3b555b4..28edba7 100644
--- a/include/linux/spinlock_rt.h
+++ b/include/linux/spinlock_rt.h
@@ -20,6 +20,7 @@ extern void __lockfunc rt_spin_lock(spinlock_t *lock);
extern unsigned long __lockfunc rt_spin_lock_trace_flags(spinlock_t *lock);
extern void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass);
extern void __lockfunc rt_spin_unlock(spinlock_t *lock);
+extern void __lockfunc rt_spin_unlock_after_trylock_in_irq(spinlock_t *lock);
extern void __lockfunc rt_spin_unlock_wait(spinlock_t *lock);
extern int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags);
extern int __lockfunc rt_spin_trylock_bh(spinlock_t *lock);
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 6075f17..d759326 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -801,10 +801,8 @@ static void noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
/*
* Slow path to release a rt_mutex spin_lock style
*/
-static void noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
+static void __sched __rt_spin_lock_slowunlock(struct rt_mutex *lock)
{
- raw_spin_lock(&lock->wait_lock);
-
debug_rt_mutex_unlock(lock);
rt_mutex_deadlock_account_unlock(current);
@@ -823,6 +821,23 @@ static void noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
rt_mutex_adjust_prio(current);
}
+static void noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
+{
+ raw_spin_lock(&lock->wait_lock);
+ __rt_spin_lock_slowunlock(lock);
+}
+
+static void noinline __sched rt_spin_lock_slowunlock_hirq(struct rt_mutex *lock)
+{
+ int ret;
+
+ do {
+ ret = raw_spin_trylock(&lock->wait_lock);
+ } while (!ret);
+
+ __rt_spin_lock_slowunlock(lock);
+}
+
void __lockfunc rt_spin_lock(spinlock_t *lock)
{
rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
@@ -853,6 +868,13 @@ void __lockfunc rt_spin_unlock(spinlock_t *lock)
}
EXPORT_SYMBOL(rt_spin_unlock);
+void __lockfunc rt_spin_unlock_after_trylock_in_irq(spinlock_t *lock)
+{
+ /* NOTE: we always pass in '1' for nested, for simplicity */
+ spin_release(&lock->dep_map, 1, _RET_IP_);
+ rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock_hirq);
+}
+
void __lockfunc __rt_spin_unlock(struct rt_mutex *lock)
{
rt_spin_lock_fastunlock(lock, rt_spin_lock_slowunlock);
@@ -1064,7 +1086,8 @@ rt_mutex_slowtrylock(struct rt_mutex *lock)
{
int ret = 0;
- raw_spin_lock(&lock->wait_lock);
+ if (!raw_spin_trylock(&lock->wait_lock))
+ return ret;
init_lists(lock);
if (likely(rt_mutex_owner(lock) != current)) {
diff --git a/kernel/timer.c b/kernel/timer.c
index 7fa30e0..b7ef082 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1336,7 +1336,7 @@ unsigned long get_next_timer_interrupt(unsigned long now)
if (time_before_eq(base->next_timer, base->timer_jiffies))
base->next_timer = __next_timer_interrupt(base);
expires = base->next_timer;
- rt_spin_unlock(&base->lock);
+ rt_spin_unlock_after_trylock_in_irq(&base->lock);
} else {
expires = now + 1;
}
--
1.8.4.3
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock
2014-01-16 1:58 ` [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock Steven Rostedt
@ 2014-01-16 3:08 ` Mike Galbraith
2014-01-17 4:22 ` Steven Rostedt
0 siblings, 1 reply; 22+ messages in thread
From: Mike Galbraith @ 2014-01-16 3:08 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, linux-rt-users, Thomas Gleixner, Carsten Emde,
Sebastian Andrzej Siewior, John Kacur
On Wed, 2014-01-15 at 20:58 -0500, Steven Rostedt wrote:
> 3.2.53-rt76-rc1 stable review patch.
> If anyone has any objections, please let me know.
Not sure this is needed without the tglx don't unconditionally raise
timer softirq patch, and with that patch applied in the form it exists
in 3.12-rt9, as well as this one, you'll still eventually deadlock.
> ------------------
>
> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
>
> Mike Galbraith captered the following:
> | >#11 [ffff88017b243e90] _raw_spin_lock at ffffffff815d2596
> | >#12 [ffff88017b243e90] rt_mutex_trylock at ffffffff815d15be
> | >#13 [ffff88017b243eb0] get_next_timer_interrupt at ffffffff81063b42
> | >#14 [ffff88017b243f00] tick_nohz_stop_sched_tick at ffffffff810bd1fd
> | >#15 [ffff88017b243f70] tick_nohz_irq_exit at ffffffff810bd7d2
> | >#16 [ffff88017b243f90] irq_exit at ffffffff8105b02d
> | >#17 [ffff88017b243fb0] reschedule_interrupt at ffffffff815db3dd
> | >--- <IRQ stack> ---
> | >#18 [ffff88017a2a9bc8] reschedule_interrupt at ffffffff815db3dd
> | > [exception RIP: task_blocks_on_rt_mutex+51]
> | >#19 [ffff88017a2a9ce0] rt_spin_lock_slowlock at ffffffff815d183c
> | >#20 [ffff88017a2a9da0] lock_timer_base.isra.35 at ffffffff81061cbf
> | >#21 [ffff88017a2a9dd0] schedule_timeout at ffffffff815cf1ce
> | >#22 [ffff88017a2a9e50] rcu_gp_kthread at ffffffff810f9bbb
> | >#23 [ffff88017a2a9ed0] kthread at ffffffff810796d5
> | >#24 [ffff88017a2a9f50] ret_from_fork at ffffffff815da04c
>
> lock_timer_base() does a try_lock() which deadlocks on the waiter lock
> not the lock itself.
> This patch takes the waiter_lock with trylock so it should work from interrupt
> context as well. If the fastpath doesn't work and the waiter_lock itself is
> taken then it seems that the lock itself taken.
> This patch also adds a "rt_spin_try_unlock" to keep lockdep happy. If we
> managed to take the wait_lock in the first place we should also be able
> to take it in the unlock path.
>
> Cc: stable-rt@vger.kernel.org
> Reported-by: Mike Galbraith <bitbucket@online.de>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
> include/linux/spinlock_rt.h | 1 +
> kernel/rtmutex.c | 31 +++++++++++++++++++++++++++----
> kernel/timer.c | 2 +-
> 3 files changed, 29 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/spinlock_rt.h b/include/linux/spinlock_rt.h
> index 3b555b4..28edba7 100644
> --- a/include/linux/spinlock_rt.h
> +++ b/include/linux/spinlock_rt.h
> @@ -20,6 +20,7 @@ extern void __lockfunc rt_spin_lock(spinlock_t *lock);
> extern unsigned long __lockfunc rt_spin_lock_trace_flags(spinlock_t *lock);
> extern void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass);
> extern void __lockfunc rt_spin_unlock(spinlock_t *lock);
> +extern void __lockfunc rt_spin_unlock_after_trylock_in_irq(spinlock_t *lock);
> extern void __lockfunc rt_spin_unlock_wait(spinlock_t *lock);
> extern int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags);
> extern int __lockfunc rt_spin_trylock_bh(spinlock_t *lock);
> diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
> index 6075f17..d759326 100644
> --- a/kernel/rtmutex.c
> +++ b/kernel/rtmutex.c
> @@ -801,10 +801,8 @@ static void noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
> /*
> * Slow path to release a rt_mutex spin_lock style
> */
> -static void noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
> +static void __sched __rt_spin_lock_slowunlock(struct rt_mutex *lock)
> {
> - raw_spin_lock(&lock->wait_lock);
> -
> debug_rt_mutex_unlock(lock);
>
> rt_mutex_deadlock_account_unlock(current);
> @@ -823,6 +821,23 @@ static void noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
> rt_mutex_adjust_prio(current);
> }
>
> +static void noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
> +{
> + raw_spin_lock(&lock->wait_lock);
> + __rt_spin_lock_slowunlock(lock);
> +}
> +
> +static void noinline __sched rt_spin_lock_slowunlock_hirq(struct rt_mutex *lock)
> +{
> + int ret;
> +
> + do {
> + ret = raw_spin_trylock(&lock->wait_lock);
> + } while (!ret);
> +
> + __rt_spin_lock_slowunlock(lock);
> +}
> +
> void __lockfunc rt_spin_lock(spinlock_t *lock)
> {
> rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
> @@ -853,6 +868,13 @@ void __lockfunc rt_spin_unlock(spinlock_t *lock)
> }
> EXPORT_SYMBOL(rt_spin_unlock);
>
> +void __lockfunc rt_spin_unlock_after_trylock_in_irq(spinlock_t *lock)
> +{
> + /* NOTE: we always pass in '1' for nested, for simplicity */
> + spin_release(&lock->dep_map, 1, _RET_IP_);
> + rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock_hirq);
> +}
> +
> void __lockfunc __rt_spin_unlock(struct rt_mutex *lock)
> {
> rt_spin_lock_fastunlock(lock, rt_spin_lock_slowunlock);
> @@ -1064,7 +1086,8 @@ rt_mutex_slowtrylock(struct rt_mutex *lock)
> {
> int ret = 0;
>
> - raw_spin_lock(&lock->wait_lock);
> + if (!raw_spin_trylock(&lock->wait_lock))
> + return ret;
> init_lists(lock);
>
> if (likely(rt_mutex_owner(lock) != current)) {
> diff --git a/kernel/timer.c b/kernel/timer.c
> index 7fa30e0..b7ef082 100644
> --- a/kernel/timer.c
> +++ b/kernel/timer.c
> @@ -1336,7 +1336,7 @@ unsigned long get_next_timer_interrupt(unsigned long now)
> if (time_before_eq(base->next_timer, base->timer_jiffies))
> base->next_timer = __next_timer_interrupt(base);
> expires = base->next_timer;
> - rt_spin_unlock(&base->lock);
> + rt_spin_unlock_after_trylock_in_irq(&base->lock);
> } else {
> expires = now + 1;
> }
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock
2014-01-16 3:08 ` Mike Galbraith
@ 2014-01-17 4:22 ` Steven Rostedt
2014-01-17 5:17 ` Mike Galbraith
0 siblings, 1 reply; 22+ messages in thread
From: Steven Rostedt @ 2014-01-17 4:22 UTC (permalink / raw)
To: Mike Galbraith
Cc: linux-kernel, linux-rt-users, Thomas Gleixner, Carsten Emde,
Sebastian Andrzej Siewior, John Kacur
On Thu, 16 Jan 2014 04:08:57 +0100
Mike Galbraith <bitbucket@online.de> wrote:
> On Wed, 2014-01-15 at 20:58 -0500, Steven Rostedt wrote:
>
>
> > 3.2.53-rt76-rc1 stable review patch.
> > If anyone has any objections, please let me know.
>
> Not sure this is needed without the tglx don't unconditionally raise
> timer softirq patch, and with that patch applied in the form it exists
> in 3.12-rt9, as well as this one, you'll still eventually deadlock.
Hmm, I'll have to take a look. This sounds to be missing from all the
stable -rt kernels. I'll be pulling in the latest updates from 3.12-rt
soon.
Thanks,
-- Steve
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock
2014-01-17 4:22 ` Steven Rostedt
@ 2014-01-17 5:17 ` Mike Galbraith
2014-01-31 22:07 ` Sebastian Andrzej Siewior
0 siblings, 1 reply; 22+ messages in thread
From: Mike Galbraith @ 2014-01-17 5:17 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, linux-rt-users, Thomas Gleixner, Carsten Emde,
Sebastian Andrzej Siewior, John Kacur
On Thu, 2014-01-16 at 23:22 -0500, Steven Rostedt wrote:
> On Thu, 16 Jan 2014 04:08:57 +0100
> Mike Galbraith <bitbucket@online.de> wrote:
>
> > On Wed, 2014-01-15 at 20:58 -0500, Steven Rostedt wrote:
> >
> >
> > > 3.2.53-rt76-rc1 stable review patch.
> > > If anyone has any objections, please let me know.
> >
> > Not sure this is needed without the tglx don't unconditionally raise
> > timer softirq patch, and with that patch applied in the form it exists
> > in 3.12-rt9, as well as this one, you'll still eventually deadlock.
>
> Hmm, I'll have to take a look. This sounds to be missing from all the
> stable -rt kernels. I'll be pulling in the latest updates from 3.12-rt
> soon.
Below are the two deadlocks I encountered with 3.12-rt9, which has both
$subject and timers-do-not-raise-softirq-unconditionally.patch applied.
With bandaids applied, no others appeared.
nohz_full_all:
PID: 508 TASK: ffff8802739ba340 CPU: 16 COMMAND: "ksoftirqd/16"
#0 [ffff880276806a40] machine_kexec at ffffffff8103bc07
#1 [ffff880276806aa0] crash_kexec at ffffffff810d56b3
#2 [ffff880276806b70] panic at ffffffff815bf8b0
#3 [ffff880276806bf0] watchdog_overflow_callback at ffffffff810fed3d
#4 [ffff880276806c10] __perf_event_overflow at ffffffff81131928
#5 [ffff880276806ca0] perf_event_overflow at ffffffff81132254
#6 [ffff880276806cb0] intel_pmu_handle_irq at ffffffff8102078f
#7 [ffff880276806de0] perf_event_nmi_handler at ffffffff815c5825
#8 [ffff880276806e10] nmi_handle at ffffffff815c4ed3
#9 [ffff880276806ea0] default_do_nmi at ffffffff815c5063
#10 [ffff880276806ed0] do_nmi at ffffffff815c5388
#11 [ffff880276806ef0] end_repeat_nmi at ffffffff815c4371
[exception RIP: _raw_spin_trylock+48]
RIP: ffffffff815c3790 RSP: ffff880276803e28 RFLAGS: 00000002
RAX: 0000000000000010 RBX: 0000000000000010 RCX: 0000000000000002
RDX: ffff880276803e28 RSI: 0000000000000018 RDI: 0000000000000001
RBP: ffffffff815c3790 R8: ffffffff815c3790 R9: 0000000000000018
R10: ffff880276803e28 R11: 0000000000000002 R12: ffffffffffffffff
R13: ffff880273a0c000 R14: ffff8802739ba340 R15: ffff880273a03fd8
ORIG_RAX: ffff880273a03fd8 CS: 0010 SS: 0018
--- <RT exception stack> ---
#12 [ffff880276803e28] _raw_spin_trylock at ffffffff815c3790
#13 [ffff880276803e30] rt_spin_lock_slowunlock_hirq at ffffffff815c2cc8
#14 [ffff880276803e50] rt_spin_unlock_after_trylock_in_irq at ffffffff815c3425
#15 [ffff880276803e60] get_next_timer_interrupt at ffffffff810684a7
#16 [ffff880276803ed0] tick_nohz_stop_sched_tick at ffffffff810c5f2e
#17 [ffff880276803f50] tick_nohz_irq_exit at ffffffff810c6333
#18 [ffff880276803f70] irq_exit at ffffffff81060065
#19 [ffff880276803f90] smp_apic_timer_interrupt at ffffffff810358f5
#20 [ffff880276803fb0] apic_timer_interrupt at ffffffff815cbf9d
--- <IRQ stack> ---
#21 [ffff880273a03b28] apic_timer_interrupt at ffffffff815cbf9d
[exception RIP: _raw_spin_lock+50]
RIP: ffffffff815c3642 RSP: ffff880273a03bd8 RFLAGS: 00000202
RAX: 0000000000008b49 RBX: ffff880272157290 RCX: ffff8802739ba340
RDX: 0000000000008b4a RSI: 0000000000000010 RDI: ffff880273a0c000
RBP: ffff880273a03bd8 R8: 0000000000000001 R9: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffffffff810927b5
R13: ffff880273a03b68 R14: 0000000000000010 R15: 0000000000000010
ORIG_RAX: ffffffffffffff10 CS: 0010 SS: 0018
#22 [ffff880273a03be0] rt_spin_lock_slowlock at ffffffff815c2591
#23 [ffff880273a03cc0] rt_spin_lock at ffffffff815c3362
#24 [ffff880273a03cd0] run_timer_softirq at ffffffff81069002
#25 [ffff880273a03d70] handle_softirq at ffffffff81060d0f
#26 [ffff880273a03db0] do_current_softirqs at ffffffff81060f3c
#27 [ffff880273a03e20] run_ksoftirqd at ffffffff81061045
#28 [ffff880273a03e40] smpboot_thread_fn at ffffffff81089c31
#29 [ffff880273a03ec0] kthread at ffffffff810807fe
#30 [ffff880273a03f50] ret_from_fork at ffffffff815cb28c
nohz_tick:
PID: 6948 TASK: ffff880272d1f1c0 CPU: 29 COMMAND: "tbench"
#0 [ffff8802769a6a40] machine_kexec at ffffffff8103bc07
#1 [ffff8802769a6aa0] crash_kexec at ffffffff810d3e93
#2 [ffff8802769a6b70] panic at ffffffff815bce70
#3 [ffff8802769a6bf0] watchdog_overflow_callback at ffffffff810fd51d
#4 [ffff8802769a6c10] __perf_event_overflow at ffffffff8112f1f8
#5 [ffff8802769a6ca0] perf_event_overflow at ffffffff8112fb14
#6 [ffff8802769a6cb0] intel_pmu_handle_irq at ffffffff8102078f
#7 [ffff8802769a6de0] perf_event_nmi_handler at ffffffff815c2de5
#8 [ffff8802769a6e10] nmi_handle at ffffffff815c2493
#9 [ffff8802769a6ea0] default_do_nmi at ffffffff815c2623
#10 [ffff8802769a6ed0] do_nmi at ffffffff815c2948
#11 [ffff8802769a6ef0] end_repeat_nmi at ffffffff815c1931
[exception RIP: preempt_schedule+36]
RIP: ffffffff815be944 RSP: ffff8802769a3d98 RFLAGS: 00000002
RAX: 0000000000000010 RBX: 0000000000000010 RCX: 0000000000000002
RDX: ffff8802769a3d98 RSI: 0000000000000018 RDI: 0000000000000001
RBP: ffffffff815be944 R8: ffffffff815be944 R9: 0000000000000018
R10: ffff8802769a3d98 R11: 0000000000000002 R12: ffffffffffffffff
R13: ffff880273f74000 R14: ffff880272d1f1c0 R15: ffff880269cedfd8
ORIG_RAX: ffff880269cedfd8 CS: 0010 SS: 0018
--- <RT exception stack> ---
#12 [ffff8802769a3d98] preempt_schedule at ffffffff815be944
#13 [ffff8802769a3db0] _raw_spin_trylock at ffffffff815c0d6e
#14 [ffff8802769a3dc0] rt_spin_lock_slowunlock_hirq at ffffffff815c0288
#15 [ffff8802769a3de0] rt_spin_unlock_after_trylock_in_irq at ffffffff815c09e5
#16 [ffff8802769a3df0] run_local_timers at ffffffff81068025
#17 [ffff8802769a3e10] update_process_times at ffffffff810680ac
#18 [ffff8802769a3e40] tick_sched_handle at ffffffff810c3a92
#19 [ffff8802769a3e60] tick_sched_timer at ffffffff810c3d2f
#20 [ffff8802769a3e90] __run_hrtimer at ffffffff8108471d
#21 [ffff8802769a3ed0] hrtimer_interrupt at ffffffff8108497a
#22 [ffff8802769a3f70] local_apic_timer_interrupt at ffffffff810349e6
#23 [ffff8802769a3f90] smp_apic_timer_interrupt at ffffffff810358ee
#24 [ffff8802769a3fb0] apic_timer_interrupt at ffffffff815c955d
--- <IRQ stack> ---
#25 [ffff880269ced848] apic_timer_interrupt at ffffffff815c955d
[exception RIP: _raw_spin_lock+53]
RIP: ffffffff815c0c05 RSP: ffff880269ced8f8 RFLAGS: 00000202
RAX: 0000000000000b7b RBX: 0000000000000282 RCX: ffff880272d1f1c0
RDX: 0000000000000b7d RSI: ffff880269ceda38 RDI: ffff880273f74000
RBP: ffff880269ced8f8 R8: 0000000000000001 R9: 00000000b54d13a4
R10: 0000000000000001 R11: 0000000000000001 R12: ffff880269ced910
R13: ffff880276d32170 R14: ffffffff810c9030 R15: ffff880269ced8b8
ORIG_RAX: ffffffffffffff10 CS: 0010 SS: 0018
#26 [ffff880269ced900] rt_spin_lock_slowlock at ffffffff815bfb51
#27 [ffff880269ced9e0] rt_spin_lock at ffffffff815c0922
#28 [ffff880269ced9f0] lock_timer_base at ffffffff81067f92
#29 [ffff880269ceda20] mod_timer at ffffffff81069bcb
#30 [ffff880269ceda70] sk_reset_timer at ffffffff814d1e57
#31 [ffff880269ceda90] inet_csk_reset_xmit_timer at ffffffff8152d4a8
#32 [ffff880269cedac0] tcp_rearm_rto at ffffffff8152d583
#33 [ffff880269cedae0] tcp_ack at ffffffff81534085
#34 [ffff880269cedb60] tcp_rcv_established at ffffffff8153443d
#35 [ffff880269cedbb0] tcp_v4_do_rcv at ffffffff8153f56a
#36 [ffff880269cedbe0] __release_sock at ffffffff814d3891
#37 [ffff880269cedc10] release_sock at ffffffff814d3942
#38 [ffff880269cedc30] tcp_sendmsg at ffffffff8152b955
#39 [ffff880269cedd00] inet_sendmsg at ffffffff8155350e
#40 [ffff880269cedd30] sock_sendmsg at ffffffff814cea87
#41 [ffff880269cede40] sys_sendto at ffffffff814cebdf
#42 [ffff880269cedf80] tracesys at ffffffff815c8b09 (via system_call)
RIP: 00007f0441a1fc35 RSP: 00007fffdea86130 RFLAGS: 00000246
RAX: ffffffffffffffda RBX: ffffffff815c8b09 RCX: ffffffffffffffff
RDX: 000000000000248d RSI: 0000000000607260 RDI: 0000000000000004
RBP: 000000000000248d R8: 0000000000000000 R9: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffdea86a10
R13: 00007fffdea86414 R14: 0000000000000004 R15: 0000000000607260
ORIG_RAX: 000000000000002c CS: 0033 SS: 002b
Unrelated to this, just FYI, hotplug is still racy in -rt, though I'm
suspecting -rt isn't really to blame. I'm trying to finger it out now.
Your stress script makes virgin -rt9 explode in get_group() ala below.
You can also end up accessing bad domain data in idle_balance().. 64
core box with no SMT enabled enters idle_balance(), and finds SIBLING
domain with groups of 0 weight, and promptly do /0 in that case.
This is virgin source running on 64 core DL980.. well, virgin plus one
trace_printk() to help asm-challenged self find stuff on the stack.
[ 4466.495899] CPU: 9 PID: 63150 Comm: stress-cpu-hotp Tainted: GF 3.12.7-rt9 #240
[ 4466.495900] Hardware name: Hewlett-Packard ProLiant DL980 G7, BIOS P66 07/07/2010
[ 4466.495901] task: ffff88026ddfbd40 ti: ffff880267486000 task.ti: ffff880267486000
[ 4466.495904] RIP: 0010:[<ffffffff8108c58f>] [<ffffffff8108c58f>] get_group+0x4f/0x80
[ 4466.495905] RSP: 0018:ffff880267487b88 EFLAGS: 00010282
[ 4466.495906] RAX: 0000000000017390 RBX: ffff8802703aba48 RCX: 0000000000000100
[ 4466.495906] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000100
[ 4466.495907] RBP: ffff880267487b98 R08: 0000000000000100 R09: ffff880270215290
[ 4466.495908] R10: ffff880270215290 R11: 0000000000000007 R12: ffff880267487bc8
[ 4466.495909] R13: ffff880270215290 R14: ffff8802703aba48 R15: 0000000000000011
[ 4466.495910] FS: 00007fb8c9390700(0000) GS:ffff880276f20000(0000) knlGS:0000000000000000
[ 4466.495911] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 4466.495912] CR2: 0000000000017390 CR3: 0000000265033000 CR4: 00000000000007e0
[ 4466.495913] Stack:
[ 4466.495917] 0000000000000012 00000000ffffffff ffff880267487bf8 ffffffff8108c6b0
[ 4466.495921] ffff8802703aba00 ffff8802682d1b40 ffff8802648b3380 ffffffff8108d2da
[ 4466.495925] ffff8802648b3380 ffff880270215200 0000000000000000 0000000000000000
[ 4466.495925] Call Trace:
[ 4466.495931] [<ffffffff8108c6b0>] build_sched_groups+0xf0/0x200
[ 4466.495934] [<ffffffff8108d2da>] ? build_sched_domain+0x5a/0xf0
[ 4466.495936] [<ffffffff8108f7ca>] build_sched_domains+0x22a/0x490
[ 4466.495939] [<ffffffff8108fbd1>] partition_sched_domains+0x1a1/0x3e0
[ 4466.495946] [<ffffffff810dfcb2>] cpuset_update_active_cpus+0x12/0x30
[ 4466.495948] [<ffffffff8108fe4c>] cpuset_cpu_active+0x3c/0x70
[ 4466.495954] [<ffffffff815c987f>] notifier_call_chain+0x3f/0x80
[ 4466.495960] [<ffffffff81085c09>] __raw_notifier_call_chain+0x9/0x10
[ 4466.495966] [<ffffffff8105a138>] _cpu_up+0x158/0x170
[ 4466.495968] [<ffffffff8105a3aa>] cpu_up+0xca/0x130
[ 4466.495974] [<ffffffff815bcc26>] cpu_subsys_online+0x56/0xb0
[ 4466.495978] [<ffffffff8141303d>] device_online+0x7d/0xa0
[ 4466.495982] [<ffffffff814149b8>] online_store+0x78/0x80
[ 4466.495989] [<ffffffff814124db>] dev_attr_store+0x1b/0x20
[ 4466.495996] [<ffffffff8121ba35>] sysfs_write_file+0xc5/0x140
[ 4466.496003] [<ffffffff811a0f27>] vfs_write+0xe7/0x190
[ 4466.496007] [<ffffffff811a187d>] SyS_write+0x5d/0xa0
[ 4466.496012] [<ffffffff815cd4b9>] system_call_fastpath+0x16/0x1b
[ 4466.496026] Code: 85 c0 74 13 48 8d b8 90 00 00 00 be 00 01 00 00 e8 c7 9d 29 00 89 c7 4d 85 e4 74 39 48 63 cf 48 8b 43 08 48 8b 14 cd 40 27 ab 81 <48> 8b 34 10 49 89 34 24 48 8b 14 cd 40 27 ab 81 48 8b 43 10 48
[ 4466.496028] RIP [<ffffffff8108c58f>] get_group+0x4f/0x80
[ 4466.496028] RSP <ffff880267487b88>
[ 4466.496029] CR2: 0000000000017390
crash> bt
PID: 63150 TASK: ffff88026ddfbd40 CPU: 9 COMMAND: "stress-cpu-hotp"
#0 [ffff880267487790] machine_kexec at ffffffff8103b9e7
#1 [ffff8802674877f0] crash_kexec at ffffffff810d3763
#2 [ffff8802674878c0] oops_end at ffffffff815c6f58
#3 [ffff8802674878f0] no_context at ffffffff81048529
#4 [ffff880267487930] __bad_area_nosemaphore at ffffffff8104873d
#5 [ffff880267487980] bad_area at ffffffff8104888c
#6 [ffff8802674879b0] __do_page_fault at ffffffff815c97ac
#7 [ffff880267487ac0] do_page_fault at ffffffff815c9839
#8 [ffff880267487ad0] page_fault at ffffffff815c6348
[exception RIP: get_group+79] core.c:5721 *sg = *per_cpu_ptr(sdd->sg, cpu)
RIP: ffffffff8108c58f RSP: ffff880267487b88 RFLAGS: 00010282
RAX: 0000000000017390 RBX: ffff8802703aba48 RCX: 0000000000000100
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000100
RBP: ffff880267487b98 R8: 0000000000000100 R9: ffff880270215290
R10: ffff880270215290 R11: 0000000000000007 R12: ffff880267487bc8
R13: ffff880270215290 R14: ffff8802703aba48 R15: 0000000000000011
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#9 [ffff880267487ba0] build_sched_groups at ffffffff8108c6b0 core.c:5763 group = get_group(i, sdd, &sg);
#10 [ffff880267487c00] build_sched_domains at ffffffff8108f7ca core.c:6407 if (build_sched_groups(sd, i))
#11 [ffff880267487c50] partition_sched_domains at ffffffff8108fbd1 core.c:6608 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
#12 [ffff880267487d00] cpuset_update_active_cpus at ffffffff810dfcb2 cpuset.c:2286 partition_sched_domains(1, NULL, NULL);
#13 [ffff880267487d10] cpuset_cpu_active at ffffffff8108fe4c core.c:6662 cpuset_update_active_cpus(true);
#14 [ffff880267487d20] notifier_call_chain at ffffffff815c987f
#15 [ffff880267487d60] __raw_notifier_call_chain at ffffffff81085c09
#16 [ffff880267487d70] _cpu_up at ffffffff8105a138
#17 [ffff880267487dc0] cpu_up at ffffffff8105a3aa
#18 [ffff880267487df0] cpu_subsys_online at ffffffff815bcc26
#19 [ffff880267487e30] device_online at ffffffff8141303d
#20 [ffff880267487e60] online_store at ffffffff814149b8
#21 [ffff880267487e90] dev_attr_store at ffffffff814124db
#22 [ffff880267487ea0] sysfs_write_file at ffffffff8121ba35
#23 [ffff880267487ef0] vfs_write at ffffffff811a0f27
#24 [ffff880267487f20] sys_write at ffffffff811a187d
#25 [ffff880267487f80] system_call_fastpath at ffffffff815cd4b9
RIP: 00007fb8c8ab31f0 RSP: 00007fff96a6f348 RFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffff815cd4b9 RCX: ffffffffffffffff
RDX: 0000000000000002 RSI: 00007fb8c93b9000 RDI: 0000000000000001
RBP: 00007fb8c93b9000 R8: 00007fb8c9390700 R9: 00007fb8c8d59e30
R10: 00007fb8c8d59e30 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff96a6f470 R14: 0000000000000002 R15: 00007fb8c8d587a0
ORIG_RAX: 0000000000000001 CS: 0033 SS: 002b
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock
2014-01-17 5:17 ` Mike Galbraith
@ 2014-01-31 22:07 ` Sebastian Andrzej Siewior
2014-02-01 4:21 ` Mike Galbraith
0 siblings, 1 reply; 22+ messages in thread
From: Sebastian Andrzej Siewior @ 2014-01-31 22:07 UTC (permalink / raw)
To: Mike Galbraith
Cc: Steven Rostedt, linux-kernel, linux-rt-users, Thomas Gleixner,
Carsten Emde, John Kacur
* Mike Galbraith | 2014-01-17 06:17:12 [+0100]:
>On Thu, 2014-01-16 at 23:22 -0500, Steven Rostedt wrote:
>> On Thu, 16 Jan 2014 04:08:57 +0100
>> Mike Galbraith <bitbucket@online.de> wrote:
>>
>> > On Wed, 2014-01-15 at 20:58 -0500, Steven Rostedt wrote:
>> >
>> >
>> > > 3.2.53-rt76-rc1 stable review patch.
>> > > If anyone has any objections, please let me know.
>> >
>> > Not sure this is needed without the tglx don't unconditionally raise
>> > timer softirq patch, and with that patch applied in the form it exists
>> > in 3.12-rt9, as well as this one, you'll still eventually deadlock.
>>
>> Hmm, I'll have to take a look. This sounds to be missing from all the
>> stable -rt kernels. I'll be pulling in the latest updates from 3.12-rt
>> soon.
>
>Below are the two deadlocks I encountered with 3.12-rt9, which has both
>$subject and timers-do-not-raise-softirq-unconditionally.patch applied.
This patch was introduced because we had a deadlock in
run_local_timers() which took a sleeping lock in hardirq context. This
seem not to be the case in v3.2 therefore I would suggest not to take
this patch here because it does not fix anything.
Mike, do you see these deadlocks with 3.12.*-rt11 as well?
Sebastian
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock
2014-01-31 22:07 ` Sebastian Andrzej Siewior
@ 2014-02-01 4:21 ` Mike Galbraith
2014-02-01 4:54 ` Mike Galbraith
0 siblings, 1 reply; 22+ messages in thread
From: Mike Galbraith @ 2014-02-01 4:21 UTC (permalink / raw)
To: Sebastian Andrzej Siewior
Cc: Steven Rostedt, linux-kernel, linux-rt-users, Thomas Gleixner,
Carsten Emde, John Kacur
On Fri, 2014-01-31 at 23:07 +0100, Sebastian Andrzej Siewior wrote:
> * Mike Galbraith | 2014-01-17 06:17:12 [+0100]:
>
> >On Thu, 2014-01-16 at 23:22 -0500, Steven Rostedt wrote:
> >> On Thu, 16 Jan 2014 04:08:57 +0100
> >> Mike Galbraith <bitbucket@online.de> wrote:
> >>
> >> > On Wed, 2014-01-15 at 20:58 -0500, Steven Rostedt wrote:
> >> >
> >> >
> >> > > 3.2.53-rt76-rc1 stable review patch.
> >> > > If anyone has any objections, please let me know.
> >> >
> >> > Not sure this is needed without the tglx don't unconditionally raise
> >> > timer softirq patch, and with that patch applied in the form it exists
> >> > in 3.12-rt9, as well as this one, you'll still eventually deadlock.
> >>
> >> Hmm, I'll have to take a look. This sounds to be missing from all the
> >> stable -rt kernels. I'll be pulling in the latest updates from 3.12-rt
> >> soon.
> >
> >Below are the two deadlocks I encountered with 3.12-rt9, which has both
> >$subject and timers-do-not-raise-softirq-unconditionally.patch applied.
>
> This patch was introduced because we had a deadlock in
> run_local_timers() which took a sleeping lock in hardirq context. This
> seem not to be the case in v3.2 therefore I would suggest not to take
> this patch here because it does not fix anything.
>
> Mike, do you see these deadlocks with 3.12.*-rt11 as well?
No. I beat 64 core box hard configured both nohz_idle and nohz_full,
the only thing that fell out was the nohz_full irqs enabled warning.
If Stevens patch didn't fix them, it did make them hide very well.
-Mike
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock
2014-02-01 4:21 ` Mike Galbraith
@ 2014-02-01 4:54 ` Mike Galbraith
0 siblings, 0 replies; 22+ messages in thread
From: Mike Galbraith @ 2014-02-01 4:54 UTC (permalink / raw)
To: Sebastian Andrzej Siewior
Cc: Steven Rostedt, linux-kernel, linux-rt-users, Thomas Gleixner,
Carsten Emde, John Kacur
On Sat, 2014-02-01 at 05:21 +0100, Mike Galbraith wrote:
> On Fri, 2014-01-31 at 23:07 +0100, Sebastian Andrzej Siewior wrote:
> > * Mike Galbraith | 2014-01-17 06:17:12 [+0100]:
> >
> > >On Thu, 2014-01-16 at 23:22 -0500, Steven Rostedt wrote:
> > >> On Thu, 16 Jan 2014 04:08:57 +0100
> > >> Mike Galbraith <bitbucket@online.de> wrote:
> > >>
> > >> > On Wed, 2014-01-15 at 20:58 -0500, Steven Rostedt wrote:
> > >> >
> > >> >
> > >> > > 3.2.53-rt76-rc1 stable review patch.
> > >> > > If anyone has any objections, please let me know.
> > >> >
> > >> > Not sure this is needed without the tglx don't unconditionally raise
> > >> > timer softirq patch, and with that patch applied in the form it exists
> > >> > in 3.12-rt9, as well as this one, you'll still eventually deadlock.
> > >>
> > >> Hmm, I'll have to take a look. This sounds to be missing from all the
> > >> stable -rt kernels. I'll be pulling in the latest updates from 3.12-rt
> > >> soon.
> > >
> > >Below are the two deadlocks I encountered with 3.12-rt9, which has both
> > >$subject and timers-do-not-raise-softirq-unconditionally.patch applied.
> >
> > This patch was introduced because we had a deadlock in
> > run_local_timers() which took a sleeping lock in hardirq context. This
> > seem not to be the case in v3.2 therefore I would suggest not to take
> > this patch here because it does not fix anything.
> >
> > Mike, do you see these deadlocks with 3.12.*-rt11 as well?
>
> No. I beat 64 core box hard configured both nohz_idle and nohz_full,
> the only thing that fell out was the nohz_full irqs enabled warning.
Oh, and the softirq pending warnings appearing under heavy load. I
hadn't gotten to chasing those, but I see they should be history.
I'll wedge the pending -rt11 fixes in, and let 64 core stress a bit
while you're kneading -rt12 dough.
-Mike
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH RT 5/8] smp: introduce a generic on_each_cpu_mask() function
2014-01-16 1:58 [PATCH RT 0/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
` (3 preceding siblings ...)
2014-01-16 1:58 ` [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock Steven Rostedt
@ 2014-01-16 1:58 ` Steven Rostedt
2014-01-16 1:58 ` [PATCH RT 6/8] smp: add func to IPI cpus based on parameter func Steven Rostedt
` (3 subsequent siblings)
8 siblings, 0 replies; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 1:58 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Gilad Ben-Yossef, Christoph Lameter, Chris Metcalf,
Peter Zijlstra, Frederic Weisbecker, Russell King, Pekka Enberg,
Matt Mackall, Rik van Riel, Andi Kleen, Sasha Levin, Mel Gorman,
Alexander Viro, Avi Kivity, Michal Nazarewicz, Kosaki Motohiro,
Milton Miller, Andrew Morton, Linus Torvalds
[-- Attachment #1: 0005-smp-introduce-a-generic-on_each_cpu_mask-function.patch --]
[-- Type: text/plain, Size: 9236 bytes --]
3.2.53-rt76-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Gilad Ben-Yossef <gilad@benyossef.com>
[ Upstream commit 3fc498f165304dc913f1d13b5ac9ab4c758ee7ab ]
We have lots of infrastructure in place to partition multi-core systems
such that we have a group of CPUs that are dedicated to specific task:
cgroups, scheduler and interrupt affinity, and cpuisol= boot parameter.
Still, kernel code will at times interrupt all CPUs in the system via IPIs
for various needs. These IPIs are useful and cannot be avoided
altogether, but in certain cases it is possible to interrupt only specific
CPUs that have useful work to do and not the entire system.
This patch set, inspired by discussions with Peter Zijlstra and Frederic
Weisbecker when testing the nohz task patch set, is a first stab at trying
to explore doing this by locating the places where such global IPI calls
are being made and turning the global IPI into an IPI for a specific group
of CPUs. The purpose of the patch set is to get feedback if this is the
right way to go for dealing with this issue and indeed, if the issue is
even worth dealing with at all. Based on the feedback from this patch set
I plan to offer further patches that address similar issue in other code
paths.
This patch creates an on_each_cpu_mask() and on_each_cpu_cond()
infrastructure API (the former derived from existing arch specific
versions in Tile and Arm) and uses them to turn several global IPI
invocation to per CPU group invocations.
Core kernel:
on_each_cpu_mask() calls a function on processors specified by cpumask,
which may or may not include the local processor.
You must not call this function with disabled interrupts or from a
hardware interrupt handler or from a bottom half handler.
arch/arm:
Note that the generic version is a little different then the Arm one:
1. It has the mask as first parameter
2. It calls the function on the calling CPU with interrupts disabled,
but this should be OK since the function is called on the other CPUs
with interrupts disabled anyway.
arch/tile:
The API is the same as the tile private one, but the generic version
also calls the function on the with interrupts disabled in UP case
This is OK since the function is called on the other CPUs
with interrupts disabled.
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Avi Kivity <avi@redhat.com>
Acked-by: Michal Nazarewicz <mina86@mina86.org>
Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com>
Cc: Milton Miller <miltonm@bga.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
arch/arm/kernel/smp_tlb.c | 20 +++++---------------
arch/tile/include/asm/smp.h | 7 -------
arch/tile/kernel/smp.c | 19 -------------------
include/linux/smp.h | 22 ++++++++++++++++++++++
kernel/smp.c | 29 +++++++++++++++++++++++++++++
5 files changed, 56 insertions(+), 41 deletions(-)
diff --git a/arch/arm/kernel/smp_tlb.c b/arch/arm/kernel/smp_tlb.c
index 7dcb352..02c5d2c 100644
--- a/arch/arm/kernel/smp_tlb.c
+++ b/arch/arm/kernel/smp_tlb.c
@@ -13,18 +13,6 @@
#include <asm/smp_plat.h>
#include <asm/tlbflush.h>
-static void on_each_cpu_mask(void (*func)(void *), void *info, int wait,
- const struct cpumask *mask)
-{
- preempt_disable();
-
- smp_call_function_many(mask, func, info, wait);
- if (cpumask_test_cpu(smp_processor_id(), mask))
- func(info);
-
- preempt_enable();
-}
-
/**********************************************************************/
/*
@@ -87,7 +75,7 @@ void flush_tlb_all(void)
void flush_tlb_mm(struct mm_struct *mm)
{
if (tlb_ops_need_broadcast())
- on_each_cpu_mask(ipi_flush_tlb_mm, mm, 1, mm_cpumask(mm));
+ on_each_cpu_mask(mm_cpumask(mm), ipi_flush_tlb_mm, mm, 1);
else
local_flush_tlb_mm(mm);
}
@@ -98,7 +86,8 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
struct tlb_args ta;
ta.ta_vma = vma;
ta.ta_start = uaddr;
- on_each_cpu_mask(ipi_flush_tlb_page, &ta, 1, mm_cpumask(vma->vm_mm));
+ on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_page,
+ &ta, 1);
} else
local_flush_tlb_page(vma, uaddr);
}
@@ -121,7 +110,8 @@ void flush_tlb_range(struct vm_area_struct *vma,
ta.ta_vma = vma;
ta.ta_start = start;
ta.ta_end = end;
- on_each_cpu_mask(ipi_flush_tlb_range, &ta, 1, mm_cpumask(vma->vm_mm));
+ on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_range,
+ &ta, 1);
} else
local_flush_tlb_range(vma, start, end);
}
diff --git a/arch/tile/include/asm/smp.h b/arch/tile/include/asm/smp.h
index 532124a..1aa759a 100644
--- a/arch/tile/include/asm/smp.h
+++ b/arch/tile/include/asm/smp.h
@@ -43,10 +43,6 @@ void evaluate_message(int tag);
/* Boot a secondary cpu */
void online_secondary(void);
-/* Call a function on a specified set of CPUs (may include this one). */
-extern void on_each_cpu_mask(const struct cpumask *mask,
- void (*func)(void *), void *info, bool wait);
-
/* Topology of the supervisor tile grid, and coordinates of boot processor */
extern HV_Topology smp_topology;
@@ -91,9 +87,6 @@ void print_disabled_cpus(void);
#else /* !CONFIG_SMP */
-#define on_each_cpu_mask(mask, func, info, wait) \
- do { if (cpumask_test_cpu(0, (mask))) func(info); } while (0)
-
#define smp_master_cpu 0
#define smp_height 1
#define smp_width 1
diff --git a/arch/tile/kernel/smp.c b/arch/tile/kernel/smp.c
index c52224d..a44e103 100644
--- a/arch/tile/kernel/smp.c
+++ b/arch/tile/kernel/smp.c
@@ -87,25 +87,6 @@ void send_IPI_allbutself(int tag)
send_IPI_many(&mask, tag);
}
-
-/*
- * Provide smp_call_function_mask, but also run function locally
- * if specified in the mask.
- */
-void on_each_cpu_mask(const struct cpumask *mask, void (*func)(void *),
- void *info, bool wait)
-{
- int cpu = get_cpu();
- smp_call_function_many(mask, func, info, wait);
- if (cpumask_test_cpu(cpu, mask)) {
- local_irq_disable();
- func(info);
- local_irq_enable();
- }
- put_cpu();
-}
-
-
/*
* Functions related to starting/stopping cpus.
*/
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 78fd0a2..742a45a 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -101,6 +101,13 @@ static inline void call_function_init(void) { }
int on_each_cpu(smp_call_func_t func, void *info, int wait);
/*
+ * Call a function on processors specified by mask, which might include
+ * the local one.
+ */
+void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
+ void *info, bool wait);
+
+/*
* Mark the boot cpu "online" so that it can call console drivers in
* printk() and can access its per-cpu storage.
*/
@@ -131,6 +138,21 @@ static inline int up_smp_call_function(smp_call_func_t func, void *info)
local_irq_enable(); \
0; \
})
+/*
+ * Note we still need to test the mask even for UP
+ * because we actually can get an empty mask from
+ * code that on SMP might call us without the local
+ * CPU in the mask.
+ */
+#define on_each_cpu_mask(mask, func, info, wait) \
+ do { \
+ if (cpumask_test_cpu(0, (mask))) { \
+ local_irq_disable(); \
+ (func)(info); \
+ local_irq_enable(); \
+ } \
+ } while (0)
+
static inline void smp_send_reschedule(int cpu) { }
#define num_booting_cpus() 1
#define smp_prepare_boot_cpu() do {} while (0)
diff --git a/kernel/smp.c b/kernel/smp.c
index 9e800b2..7b4e359 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -712,3 +712,32 @@ int on_each_cpu(void (*func) (void *info), void *info, int wait)
return ret;
}
EXPORT_SYMBOL(on_each_cpu);
+
+/**
+ * on_each_cpu_mask(): Run a function on processors specified by
+ * cpumask, which may include the local processor.
+ * @mask: The set of cpus to run on (only runs on online subset).
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: If true, wait (atomically) until function has completed
+ * on other CPUs.
+ *
+ * If @wait is true, then returns once @func has returned.
+ *
+ * You must not call this function with disabled interrupts or
+ * from a hardware interrupt handler or from a bottom half handler.
+ */
+void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
+ void *info, bool wait)
+{
+ int cpu = get_cpu();
+
+ smp_call_function_many(mask, func, info, wait);
+ if (cpumask_test_cpu(cpu, mask)) {
+ local_irq_disable();
+ func(info);
+ local_irq_enable();
+ }
+ put_cpu();
+}
+EXPORT_SYMBOL(on_each_cpu_mask);
--
1.8.4.3
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH RT 6/8] smp: add func to IPI cpus based on parameter func
2014-01-16 1:58 [PATCH RT 0/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
` (4 preceding siblings ...)
2014-01-16 1:58 ` [PATCH RT 5/8] smp: introduce a generic on_each_cpu_mask() function Steven Rostedt
@ 2014-01-16 1:58 ` Steven Rostedt
2014-01-16 1:58 ` [PATCH RT 7/8] fs: only send IPI to invalidate LRU BH when needed Steven Rostedt
` (2 subsequent siblings)
8 siblings, 0 replies; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 1:58 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Gilad Ben-Yossef, Chris Metcalf, Christoph Lameter,
Peter Zijlstra, Frederic Weisbecker, Russell King, Pekka Enberg,
Matt Mackall, Sasha Levin, Rik van Riel, Andi Kleen,
Alexander Viro, Avi Kivity, Michal Nazarewicz, Kosaki Motohiro,
Milton Miller, Srivatsa S. Bhat, Andrew Morton, Linus Torvalds
[-- Attachment #1: 0006-smp-add-func-to-IPI-cpus-based-on-parameter-func.patch --]
[-- Type: text/plain, Size: 5827 bytes --]
3.2.53-rt76-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Gilad Ben-Yossef <gilad@benyossef.com>
[ Upstream commit b3a7e98e024ffa9f7e4554dd720c508015c4a831 ]
Add the on_each_cpu_cond() function that wraps on_each_cpu_mask() and
calculates the cpumask of cpus to IPI by calling a function supplied as a
parameter in order to determine whether to IPI each specific cpu.
The function works around allocation failure of cpumask variable in
CONFIG_CPUMASK_OFFSTACK=y by itereating over cpus sending an IPI a time
via smp_call_function_single().
The function is useful since it allows to seperate the specific code that
decided in each case whether to IPI a specific cpu for a specific request
from the common boilerplate code of handling creating the mask, handling
failures etc.
[akpm@linux-foundation.org: s/gfpflags/gfp_flags/]
[akpm@linux-foundation.org: avoid double-evaluation of `info' (per Michal), parenthesise evaluation of `cond_func']
[akpm@linux-foundation.org: s/CPU/CPUs, use all 80 cols in comment]
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Avi Kivity <avi@redhat.com>
Acked-by: Michal Nazarewicz <mina86@mina86.org>
Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com>
Cc: Milton Miller <miltonm@bga.com>
Reviewed-by: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/smp.h | 24 +++++++++++++++++++++
kernel/smp.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 85 insertions(+)
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 742a45a..3001ba5 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -108,6 +108,15 @@ void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
void *info, bool wait);
/*
+ * Call a function on each processor for which the supplied function
+ * cond_func returns a positive value. This may include the local
+ * processor.
+ */
+void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
+ smp_call_func_t func, void *info, bool wait,
+ gfp_t gfp_flags);
+
+/*
* Mark the boot cpu "online" so that it can call console drivers in
* printk() and can access its per-cpu storage.
*/
@@ -152,6 +161,21 @@ static inline int up_smp_call_function(smp_call_func_t func, void *info)
local_irq_enable(); \
} \
} while (0)
+/*
+ * Preemption is disabled here to make sure the cond_func is called under the
+ * same condtions in UP and SMP.
+ */
+#define on_each_cpu_cond(cond_func, func, info, wait, gfp_flags)\
+ do { \
+ void *__info = (info); \
+ preempt_disable(); \
+ if ((cond_func)(0, __info)) { \
+ local_irq_disable(); \
+ (func)(__info); \
+ local_irq_enable(); \
+ } \
+ preempt_enable(); \
+ } while (0)
static inline void smp_send_reschedule(int cpu) { }
#define num_booting_cpus() 1
diff --git a/kernel/smp.c b/kernel/smp.c
index 7b4e359..d5f3238 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -741,3 +741,64 @@ void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
put_cpu();
}
EXPORT_SYMBOL(on_each_cpu_mask);
+
+/*
+ * on_each_cpu_cond(): Call a function on each processor for which
+ * the supplied function cond_func returns true, optionally waiting
+ * for all the required CPUs to finish. This may include the local
+ * processor.
+ * @cond_func: A callback function that is passed a cpu id and
+ * the the info parameter. The function is called
+ * with preemption disabled. The function should
+ * return a blooean value indicating whether to IPI
+ * the specified CPU.
+ * @func: The function to run on all applicable CPUs.
+ * This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to both functions.
+ * @wait: If true, wait (atomically) until function has
+ * completed on other CPUs.
+ * @gfp_flags: GFP flags to use when allocating the cpumask
+ * used internally by the function.
+ *
+ * The function might sleep if the GFP flags indicates a non
+ * atomic allocation is allowed.
+ *
+ * Preemption is disabled to protect against CPUs going offline but not online.
+ * CPUs going online during the call will not be seen or sent an IPI.
+ *
+ * You must not call this function with disabled interrupts or
+ * from a hardware interrupt handler or from a bottom half handler.
+ */
+void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
+ smp_call_func_t func, void *info, bool wait,
+ gfp_t gfp_flags)
+{
+ cpumask_var_t cpus;
+ int cpu, ret;
+
+ might_sleep_if(gfp_flags & __GFP_WAIT);
+
+ if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) {
+ preempt_disable();
+ for_each_online_cpu(cpu)
+ if (cond_func(cpu, info))
+ cpumask_set_cpu(cpu, cpus);
+ on_each_cpu_mask(cpus, func, info, wait);
+ preempt_enable();
+ free_cpumask_var(cpus);
+ } else {
+ /*
+ * No free cpumask, bother. No matter, we'll
+ * just have to IPI them one by one.
+ */
+ preempt_disable();
+ for_each_online_cpu(cpu)
+ if (cond_func(cpu, info)) {
+ ret = smp_call_function_single(cpu, func,
+ info, wait);
+ WARN_ON_ONCE(!ret);
+ }
+ preempt_enable();
+ }
+}
+EXPORT_SYMBOL(on_each_cpu_cond);
--
1.8.4.3
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH RT 7/8] fs: only send IPI to invalidate LRU BH when needed
2014-01-16 1:58 [PATCH RT 0/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
` (5 preceding siblings ...)
2014-01-16 1:58 ` [PATCH RT 6/8] smp: add func to IPI cpus based on parameter func Steven Rostedt
@ 2014-01-16 1:58 ` Steven Rostedt
2014-01-16 1:58 ` [PATCH RT 8/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
2014-01-16 9:41 ` [PATCH RT 0/8] " Pavel Vasilyev
8 siblings, 0 replies; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 1:58 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Gilad Ben-Yossef, Peter Zijlstra, Alexander Viro,
Andrew Morton, Linus Torvalds
[-- Attachment #1: 0007-fs-only-send-IPI-to-invalidate-LRU-BH-when-needed.patch --]
[-- Type: text/plain, Size: 1946 bytes --]
3.2.53-rt76-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Gilad Ben-Yossef <gilad@benyossef.com>
[ Upstream commit 42be35d0390b966253136a285f507f5ad00fd9e8 ]
In several code paths, such as when unmounting a file system (but not
only) we send an IPI to ask each cpu to invalidate its local LRU BHs.
For multi-cores systems that have many cpus that may not have any LRU BH
because they are idle or because they have not performed any file system
accesses since last invalidation (e.g. CPU crunching on high perfomance
computing nodes that write results to shared memory or only using
filesystems that do not use the bh layer.) This can lead to loss of
performance each time someone switches the KVM (the virtual keyboard and
screen type, not the hypervisor) if it has a USB storage stuck in.
This patch attempts to only send an IPI to cpus that have LRU BH.
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
fs/buffer.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 997b199..36d49f1 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1425,10 +1425,23 @@ static void invalidate_bh_lru(void *arg)
}
put_cpu_var(bh_lrus);
}
+
+static bool has_bh_in_lru(int cpu, void *dummy)
+{
+ struct bh_lru *b = per_cpu_ptr(&bh_lrus, cpu);
+ int i;
+ for (i = 0; i < BH_LRU_SIZE; i++) {
+ if (b->bhs[i])
+ return 1;
+ }
+
+ return 0;
+}
+
void invalidate_bh_lrus(void)
{
- on_each_cpu(invalidate_bh_lru, NULL, 1);
+ on_each_cpu_cond(has_bh_in_lru, invalidate_bh_lru, NULL, 1, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(invalidate_bh_lrus);
--
1.8.4.3
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH RT 8/8] Linux 3.2.53-rt76-rc1
2014-01-16 1:58 [PATCH RT 0/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
` (6 preceding siblings ...)
2014-01-16 1:58 ` [PATCH RT 7/8] fs: only send IPI to invalidate LRU BH when needed Steven Rostedt
@ 2014-01-16 1:58 ` Steven Rostedt
2014-01-16 9:41 ` [PATCH RT 0/8] " Pavel Vasilyev
8 siblings, 0 replies; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 1:58 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior, John Kacur
[-- Attachment #1: 0008-Linux-3.2.53-rt76-rc1.patch --]
[-- Type: text/plain, Size: 405 bytes --]
3.2.53-rt76-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
---
localversion-rt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/localversion-rt b/localversion-rt
index 54e7da6..bd9bb72 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt75
+-rt76-rc1
--
1.8.4.3
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [PATCH RT 0/8] Linux 3.2.53-rt76-rc1
2014-01-16 1:58 [PATCH RT 0/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
` (7 preceding siblings ...)
2014-01-16 1:58 ` [PATCH RT 8/8] Linux 3.2.53-rt76-rc1 Steven Rostedt
@ 2014-01-16 9:41 ` Pavel Vasilyev
2014-01-16 14:18 ` Steven Rostedt
8 siblings, 1 reply; 22+ messages in thread
From: Pavel Vasilyev @ 2014-01-16 9:41 UTC (permalink / raw)
To: Steven Rostedt, linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior, John Kacur
[-- Attachment #1: Type: text/plain, Size: 240 bytes --]
16.01.2014 05:58, Steven Rostedt пишет:
> Dear RT Folks,
>
> This is the RT stable review cycle of patch 3.2.53-rt76-rc1.
Yap..., mainline is 3.2.54 !
--
Pavel.
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH RT 0/8] Linux 3.2.53-rt76-rc1
2014-01-16 9:41 ` [PATCH RT 0/8] " Pavel Vasilyev
@ 2014-01-16 14:18 ` Steven Rostedt
2014-01-16 14:36 ` Pavel Vasilyev
0 siblings, 1 reply; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 14:18 UTC (permalink / raw)
To: pavel
Cc: linux-kernel, linux-rt-users, Thomas Gleixner, Carsten Emde,
Sebastian Andrzej Siewior, John Kacur
On Thu, 16 Jan 2014 13:41:16 +0400
Pavel Vasilyev <pavel@pavlinux.ru> wrote:
> 16.01.2014 05:58, Steven Rostedt пишет:
> > Dear RT Folks,
> >
> > This is the RT stable review cycle of patch 3.2.53-rt76-rc1.
>
> Yap..., mainline is 3.2.54 !
>
Yeah, but I already had the -rt specific changes merged into 3.2.53
before 3.2.54 was released, and then I discovered the cpu hotplug bug.
I did not want to release that -rc until it was solved. Now that it is,
I can release this one and then move to 3.2.54.
Thanks,
-- Steve
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH RT 0/8] Linux 3.2.53-rt76-rc1
2014-01-16 14:18 ` Steven Rostedt
@ 2014-01-16 14:36 ` Pavel Vasilyev
2014-01-16 15:09 ` Steven Rostedt
` (2 more replies)
0 siblings, 3 replies; 22+ messages in thread
From: Pavel Vasilyev @ 2014-01-16 14:36 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, linux-rt-users, Thomas Gleixner, Carsten Emde,
Sebastian Andrzej Siewior, John Kacur
[-- Attachment #1: Type: text/plain, Size: 1566 bytes --]
16.01.2014 18:18, Steven Rostedt пишет:
> On Thu, 16 Jan 2014 13:41:16 +0400
> Pavel Vasilyev <pavel@pavlinux.ru> wrote:
>
>> 16.01.2014 05:58, Steven Rostedt пишет:
>>> Dear RT Folks,
>>>
>>> This is the RT stable review cycle of patch 3.2.53-rt76-rc1.
>>
>> Yap..., mainline is 3.2.54 !
>>
>
> Yeah, but I already had the -rt specific changes merged into 3.2.53
> before 3.2.54 was released, and then I discovered the cpu hotplug bug.
> I did not want to release that -rc until it was solved. Now that it is,
> I can release this one and then move to 3.2.54.
$ xz -cd /tmp/patch-3.2.53-rt75-rt76-rc1.patch.xz | patch -p1 --dry-run
checking file arch/arm/kernel/smp_tlb.c
checking file arch/tile/include/asm/smp.h
checking file arch/tile/kernel/smp.c
checking file drivers/net/wireless/orinoco/orinoco_usb.c
checking file drivers/usb/gadget/f_fs.c
checking file drivers/usb/gadget/inode.c
checking file fs/buffer.c
checking file include/linux/smp.h
Hunk #1 succeeded at 117 with fuzz 1 (offset 16 lines).
Hunk #2 FAILED at 147.
1 out of 2 hunks FAILED
checking file include/linux/spinlock_rt.h
checking file kernel/cpu.c
checking file kernel/rtmutex.c
checking file kernel/smp.c
Hunk #1 FAILED at 712.
1 out of 1 hunk FAILED
checking file kernel/softirq.c
checking file kernel/timer.c
checking file localversion-rt
include/linux/smp.h REJECT: #define on_each_cpu_mask() and #define
on_each_cpu_cond() and same in kernel/smp.c
--
Pavel.
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH RT 0/8] Linux 3.2.53-rt76-rc1
2014-01-16 14:36 ` Pavel Vasilyev
@ 2014-01-16 15:09 ` Steven Rostedt
2014-01-16 16:08 ` Steven Rostedt
2014-01-16 16:18 ` Sebastian Andrzej Siewior
2 siblings, 0 replies; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 15:09 UTC (permalink / raw)
To: pavel
Cc: linux-kernel, linux-rt-users, Thomas Gleixner, Carsten Emde,
Sebastian Andrzej Siewior, John Kacur
On Thu, 16 Jan 2014 18:36:32 +0400
Pavel Vasilyev <pavel@pavlinux.ru> wrote:
> 16.01.2014 18:18, Steven Rostedt пишет:
> > On Thu, 16 Jan 2014 13:41:16 +0400
> > Pavel Vasilyev <pavel@pavlinux.ru> wrote:
> >
> >> 16.01.2014 05:58, Steven Rostedt пишет:
> >>> Dear RT Folks,
> >>>
> >>> This is the RT stable review cycle of patch 3.2.53-rt76-rc1.
> >>
> >> Yap..., mainline is 3.2.54 !
> >>
> >
> > Yeah, but I already had the -rt specific changes merged into 3.2.53
> > before 3.2.54 was released, and then I discovered the cpu hotplug bug.
> > I did not want to release that -rc until it was solved. Now that it is,
> > I can release this one and then move to 3.2.54.
>
>
> $ xz -cd /tmp/patch-3.2.53-rt75-rt76-rc1.patch.xz | patch -p1 --dry-run
>
> checking file arch/arm/kernel/smp_tlb.c
> checking file arch/tile/include/asm/smp.h
> checking file arch/tile/kernel/smp.c
> checking file drivers/net/wireless/orinoco/orinoco_usb.c
> checking file drivers/usb/gadget/f_fs.c
> checking file drivers/usb/gadget/inode.c
> checking file fs/buffer.c
> checking file include/linux/smp.h
> Hunk #1 succeeded at 117 with fuzz 1 (offset 16 lines).
> Hunk #2 FAILED at 147.
> 1 out of 2 hunks FAILED
> checking file include/linux/spinlock_rt.h
> checking file kernel/cpu.c
> checking file kernel/rtmutex.c
> checking file kernel/smp.c
> Hunk #1 FAILED at 712.
> 1 out of 1 hunk FAILED
> checking file kernel/softirq.c
> checking file kernel/timer.c
> checking file localversion-rt
>
>
> include/linux/smp.h REJECT: #define on_each_cpu_mask() and #define
> on_each_cpu_cond() and same in kernel/smp.c
>
>
Ouch, thanks for letting me know. I'll give it a try to make sure that
the patch is the same code that I tested.
-- Steve
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH RT 0/8] Linux 3.2.53-rt76-rc1
2014-01-16 14:36 ` Pavel Vasilyev
2014-01-16 15:09 ` Steven Rostedt
@ 2014-01-16 16:08 ` Steven Rostedt
2014-01-16 17:19 ` Pavel Vasilyev
2014-01-16 16:18 ` Sebastian Andrzej Siewior
2 siblings, 1 reply; 22+ messages in thread
From: Steven Rostedt @ 2014-01-16 16:08 UTC (permalink / raw)
To: pavel
Cc: linux-kernel, linux-rt-users, Thomas Gleixner, Carsten Emde,
Sebastian Andrzej Siewior, John Kacur
On Thu, 16 Jan 2014 18:36:32 +0400
Pavel Vasilyev <pavel@pavlinux.ru> wrote:
>
> $ xz -cd /tmp/patch-3.2.53-rt75-rt76-rc1.patch.xz | patch -p1 --dry-run
>
> checking file arch/arm/kernel/smp_tlb.c
> checking file arch/tile/include/asm/smp.h
> checking file arch/tile/kernel/smp.c
> checking file drivers/net/wireless/orinoco/orinoco_usb.c
> checking file drivers/usb/gadget/f_fs.c
> checking file drivers/usb/gadget/inode.c
> checking file fs/buffer.c
> checking file include/linux/smp.h
> Hunk #1 succeeded at 117 with fuzz 1 (offset 16 lines).
> Hunk #2 FAILED at 147.
> 1 out of 2 hunks FAILED
> checking file include/linux/spinlock_rt.h
> checking file kernel/cpu.c
> checking file kernel/rtmutex.c
> checking file kernel/smp.c
> Hunk #1 FAILED at 712.
> 1 out of 1 hunk FAILED
> checking file kernel/softirq.c
> checking file kernel/timer.c
> checking file localversion-rt
>
>
> include/linux/smp.h REJECT: #define on_each_cpu_mask() and #define
> on_each_cpu_cond() and same in kernel/smp.c
>
>
$ git checkout v3.2.53-rt75
[..]
$ xzcat /tmp/patch-3.2.53-rt75-rt76-rc1.patch.xz | patch -p1 --dry-run
checking file arch/arm/kernel/smp_tlb.c
checking file arch/tile/include/asm/smp.h
checking file arch/tile/kernel/smp.c
checking file drivers/net/wireless/orinoco/orinoco_usb.c
checking file drivers/usb/gadget/f_fs.c
checking file drivers/usb/gadget/inode.c
checking file fs/buffer.c
checking file include/linux/smp.h
checking file include/linux/spinlock_rt.h
checking file kernel/cpu.c
checking file kernel/rtmutex.c
checking file kernel/smp.c
checking file kernel/softirq.c
checking file kernel/timer.c
checking file localversion-rt
$
Did you start with v3.2.53-rt75?
-- Steve
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH RT 0/8] Linux 3.2.53-rt76-rc1
2014-01-16 16:08 ` Steven Rostedt
@ 2014-01-16 17:19 ` Pavel Vasilyev
0 siblings, 0 replies; 22+ messages in thread
From: Pavel Vasilyev @ 2014-01-16 17:19 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, linux-rt-users, Thomas Gleixner, Carsten Emde,
Sebastian Andrzej Siewior, John Kacur
[-- Attachment #1: Type: text/plain, Size: 361 bytes --]
16.01.2014 20:08, Steven Rostedt пишет:
> On Thu, 16 Jan 2014 18:36:32 +0400
> Pavel Vasilyev <pavel@pavlinux.ru> wrote:
>
>>
>> $ xz -cd /tmp/patch-3.2.53-rt75-rt76-rc1.patch.xz | patch -p1 --dry-run
> Did you start with v3.2.53-rt75?
No, 3.2.54, already corrected.
--
Pavel.
[-- Attachment #2: OpenPGP digital signature --]
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^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH RT 0/8] Linux 3.2.53-rt76-rc1
2014-01-16 14:36 ` Pavel Vasilyev
2014-01-16 15:09 ` Steven Rostedt
2014-01-16 16:08 ` Steven Rostedt
@ 2014-01-16 16:18 ` Sebastian Andrzej Siewior
2 siblings, 0 replies; 22+ messages in thread
From: Sebastian Andrzej Siewior @ 2014-01-16 16:18 UTC (permalink / raw)
To: pavel
Cc: Steven Rostedt, linux-kernel, linux-rt-users, Thomas Gleixner,
Carsten Emde, John Kacur
On 01/16/2014 03:36 PM, Pavel Vasilyev wrote:
> $ xz -cd /tmp/patch-3.2.53-rt75-rt76-rc1.patch.xz | patch -p1
> --dry-run
>
…
> checking file include/linux/smp.h Hunk #1 succeeded at 117 with
> fuzz 1 (offset 16 lines). Hunk #2 FAILED at 147. 1 out of 2 hunks
> FAILED
I just fetched the 3.2.53 tar file & Steven's patches and I applied
the incremental patch and the all-in-one patch and I don't see this
fallout.
Sebastian
^ permalink raw reply [flat|nested] 22+ messages in thread