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10 Dec 2020 09:42:58 -0800 Date: Thu, 10 Dec 2020 09:37:13 -0800 From: Matthew Brost To: Chris Wilson Message-ID: <20201210173713.GA25527@sdutt-i7> References: <20201207193824.18114-1-chris@chris-wilson.co.uk> <20201207193824.18114-7-chris@chris-wilson.co.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201207193824.18114-7-chris@chris-wilson.co.uk> User-Agent: Mutt/1.9.4 (2018-02-28) Subject: Re: [Intel-gfx] [PATCH 07/20] drm/i915/gt: Shrink the critical section for irq signaling X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Mon, Dec 07, 2020 at 07:38:11PM +0000, Chris Wilson wrote: > Let's only wait for the list iterator when decoupling the virtual > breadcrumb, as the signaling of all the requests may take a long time, > during which we do not want to keep the tasklet spinning. > > Signed-off-by: Chris Wilson > --- > drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 2 ++ > drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h | 1 + > drivers/gpu/drm/i915/gt/intel_lrc.c | 3 ++- > 3 files changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c > index 63900edbde88..ac1e5f6c3c2c 100644 > --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c > +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c > @@ -239,6 +239,7 @@ static void signal_irq_work(struct irq_work *work) > intel_breadcrumbs_disarm_irq(b); > > rcu_read_lock(); > + atomic_inc(&b->signaler_active); > list_for_each_entry_rcu(ce, &b->signalers, signal_link) { > struct i915_request *rq; > > @@ -274,6 +275,7 @@ static void signal_irq_work(struct irq_work *work) > } > } > } > + atomic_dec(&b->signaler_active); > rcu_read_unlock(); > > llist_for_each_safe(signal, sn, signal) { > diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h > index a74bb3062bd8..f672053d694d 100644 > --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h > +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h > @@ -35,6 +35,7 @@ struct intel_breadcrumbs { > spinlock_t signalers_lock; /* protects the list of signalers */ > struct list_head signalers; > struct llist_head signaled_requests; > + atomic_t signaler_active; > > spinlock_t irq_lock; /* protects the interrupt from hardirq context */ > struct irq_work irq_work; /* for use from inside irq_lock */ > diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c > index b3db16b2a5a4..35cded25c6c1 100644 > --- a/drivers/gpu/drm/i915/gt/intel_lrc.c > +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c > @@ -1401,7 +1401,8 @@ static void kick_siblings(struct i915_request *rq, struct intel_context *ce) > * ce->signal_link. > */ > i915_request_cancel_breadcrumb(rq); > - irq_work_sync(&engine->breadcrumbs->irq_work); > + while (atomic_read(&engine->breadcrumbs->signaler_active)) > + cpu_relax(); Would a 'cond_resched' be better here? I trust your opinion on which to use but thought I'd mention it. With that: Reviewed-by: Matthew Brost > } > > if (READ_ONCE(ve->request)) > -- > 2.20.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx