From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Subject: [CI 2/2] drm/i915: Don't disable interrupts independently of the lock
Date: Thu, 17 Oct 2019 16:42:08 +0100 [thread overview]
Message-ID: <20191017154208.20128-2-chris@chris-wilson.co.uk> (raw)
In-Reply-To: <20191017154208.20128-1-chris@chris-wilson.co.uk>
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
The locks (active.lock and rq->lock) need to be taken with disabled
interrupts. This is done in i915_request_retire() by disabling the
interrupts independently of the locks itself.
While local_irq_disable()+spin_lock() equals spin_lock_irq() on vanilla
it does not on PREEMPT_RT.
Chris Wilson confirmed that local_irq_disable() was just introduced as
an optimisation to avoid enabling/disabling interrupts during
lock/unlock combo.
Enable/disable interrupts as part of the locking instruction.
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_request.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index f1cadad4e81c..4575f368455d 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -206,14 +206,14 @@ static void remove_from_engine(struct i915_request *rq)
* check that the rq still belongs to the newly locked engine.
*/
locked = READ_ONCE(rq->engine);
- spin_lock(&locked->active.lock);
+ spin_lock_irq(&locked->active.lock);
while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
spin_unlock(&locked->active.lock);
spin_lock(&engine->active.lock);
locked = engine;
}
list_del(&rq->sched.link);
- spin_unlock(&locked->active.lock);
+ spin_unlock_irq(&locked->active.lock);
}
bool i915_request_retire(struct i915_request *rq)
@@ -242,8 +242,6 @@ bool i915_request_retire(struct i915_request *rq)
&i915_request_timeline(rq)->requests));
rq->ring->head = rq->postfix;
- local_irq_disable();
-
/*
* We only loosely track inflight requests across preemption,
* and so we may find ourselves attempting to retire a _completed_
@@ -252,7 +250,7 @@ bool i915_request_retire(struct i915_request *rq)
*/
remove_from_engine(rq);
- spin_lock(&rq->lock);
+ spin_lock_irq(&rq->lock);
i915_request_mark_complete(rq);
if (!i915_request_signaled(rq))
dma_fence_signal_locked(&rq->fence);
@@ -267,9 +265,7 @@ bool i915_request_retire(struct i915_request *rq)
__notify_execute_cb(rq);
}
GEM_BUG_ON(!list_empty(&rq->execute_cb));
- spin_unlock(&rq->lock);
-
- local_irq_enable();
+ spin_unlock_irq(&rq->lock);
remove_from_client(rq);
list_del(&rq->link);
--
2.23.0
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2019-10-17 15:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-17 15:42 [CI 1/2] drm/i915/execlists: Don't merely skip submission if maybe timeslicing Chris Wilson
2019-10-17 15:42 ` Chris Wilson [this message]
2019-10-17 18:54 ` ✗ Fi.CI.CHECKPATCH: warning for series starting with [CI,1/2] " Patchwork
2019-10-17 19:47 ` ✗ Fi.CI.BAT: failure " Patchwork
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191017154208.20128-2-chris@chris-wilson.co.uk \
--to=chris@chris-wilson.co.uk \
--cc=intel-gfx@lists.freedesktop.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.