lkml.org 
[lkml]   [2020]   [Feb]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [ANNOUNCE] v5.4.17-rt9
From
Date
On 2/6/20 10:11 PM, Mike Galbraith wrote:
> On Thu, 2020-02-06 at 15:59 -0800, Fernando Lopez-Lezcano wrote:
>> On 2/4/20 8:58 AM, Sebastian Andrzej Siewior wrote:
>>> Dear RT folks!
>>>
>>> I'm pleased to announce the v5.4.17-rt9 patch set.
>>
>> Thanks!
>> I see a continuous stream of these:
>
> (snips gripage)
>
> Yup, d67739268cf0 annoys RT locking if lockdep is enabled. The below
> shut it up for my i915 equipped lappy.

Wow, Mike, thanks!, will try it out and report...
(might take me a couple of days)

-- Fernando


> drm/i915/gt: use a LOCAL_IRQ_LOCK in __timeline_mark_lock()
>
> Quoting drm/i915/gt: Mark up the nested engine-pm timeline lock as irqsafe
>
> We use a fake timeline->mutex lock to reassure lockdep that the timeline
> is always locked when emitting requests. However, the use inside
> __engine_park() may be inside hardirq and so lockdep now complains about
> the mixed irq-state of the nested locked. Disable irqs around the
> lockdep tracking to keep it happy.
>
> This lockdep appeasement breaks RT because we take sleeping locks between
> __timeline_mark_lock()/unlock(). Use a LOCAL_IRQ_LOCK instead.
>
> Signed-off-by: Mike Galbraith <efaukt@gmx.de>
> ---
> drivers/gpu/drm/i915/gt/intel_engine_pm.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> --- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
> @@ -38,12 +38,15 @@ static int __engine_unpark(struct intel_
> }
>
> #if IS_ENABLED(CONFIG_LOCKDEP)
> +#include <linux/locallock.h>
> +
> +static DEFINE_LOCAL_IRQ_LOCK(timeline_lock);
>
> static inline unsigned long __timeline_mark_lock(struct intel_context *ce)
> {
> unsigned long flags;
>
> - local_irq_save(flags);
> + local_lock_irqsave(timeline_lock, flags);
> mutex_acquire(&ce->timeline->mutex.dep_map, 2, 0, _THIS_IP_);
>
> return flags;
> @@ -53,7 +56,7 @@ static inline void __timeline_mark_unloc
> unsigned long flags)
> {
> mutex_release(&ce->timeline->mutex.dep_map, 0, _THIS_IP_);
> - local_irq_restore(flags);
> + local_unlock_irqrestore(timeline_lock, flags);
> }
>
> #else
>
>


\
 
 \ /
  Last update: 2020-02-07 07:15    [W:0.042 / U:0.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site