From: Andrzej Hajda <andrzej.hajda@intel.com>
To: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>,
intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org,
Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Tvrtko Ursulin <tursulin@ursulin.net>,
Andi Shyti <andi.shyti@linux.intel.com>,
Chris Wilson <chris.p.wilson@linux.intel.com>
Subject: Re: [PATCH] drm/i915/gt: Disarm breadcrumbs if engines are already idle
Date: Thu, 9 May 2024 14:41:19 +0200 [thread overview]
Message-ID: <b086ed94-f562-48af-97a1-2e472d3c2125@intel.com> (raw)
In-Reply-To: <20240423165505.465734-2-janusz.krzysztofik@linux.intel.com>
On 23.04.2024 18:23, Janusz Krzysztofik wrote:
> From: Chris Wilson <chris@chris-wilson.co.uk>
>
> The breadcrumbs use a GT wakeref for guarding the interrupt, but are
> disarmed during release of the engine wakeref. This leaves a hole where
> we may attach a breadcrumb just as the engine is parking (after it has
> parked its breadcrumbs), execute the irq worker with some signalers still
> attached, but never be woken again.
>
> That issue manifests itself in CI with IGT runner timeouts while tests
> are waiting indefinitely for release of all GT wakerefs.
>
> <6> [209.151778] i915: Running live_engine_pm_selftests/live_engine_busy_stats
> <7> [209.231628] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling PW_5
> <7> [209.231816] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling PW_4
> <7> [209.231944] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling PW_3
> <7> [209.232056] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling PW_2
> <7> [209.232166] i915 0000:00:02.0: [drm:intel_power_well_disable [i915]] disabling DC_off
> <7> [209.232270] i915 0000:00:02.0: [drm:skl_enable_dc6 [i915]] Enabling DC6
> <7> [209.232368] i915 0000:00:02.0: [drm:gen9_set_dc_state.part.0 [i915]] Setting DC state from 00 to 02
> <4> [299.356116] [IGT] Inactivity timeout exceeded. Killing the current test with SIGQUIT.
> ...
> <6> [299.356526] sysrq: Show State
> ...
> <6> [299.373964] task:i915_selftest state:D stack:11784 pid:5578 tgid:5578 ppid:873 flags:0x00004002
> <6> [299.373967] Call Trace:
> <6> [299.373968] <TASK>
> <6> [299.373970] __schedule+0x3bb/0xda0
> <6> [299.373974] schedule+0x41/0x110
> <6> [299.373976] intel_wakeref_wait_for_idle+0x82/0x100 [i915]
> <6> [299.374083] ? __pfx_var_wake_function+0x10/0x10
> <6> [299.374087] live_engine_busy_stats+0x9b/0x500 [i915]
> <6> [299.374173] __i915_subtests+0xbe/0x240 [i915]
> <6> [299.374277] ? __pfx___intel_gt_live_setup+0x10/0x10 [i915]
> <6> [299.374369] ? __pfx___intel_gt_live_teardown+0x10/0x10 [i915]
> <6> [299.374456] intel_engine_live_selftests+0x1c/0x30 [i915]
> <6> [299.374547] __run_selftests+0xbb/0x190 [i915]
> <6> [299.374635] i915_live_selftests+0x4b/0x90 [i915]
> <6> [299.374717] i915_pci_probe+0x10d/0x210 [i915]
>
> At the end of the interrupt worker, if there are no more engines awake,
> disarm the breadcrumb and go to sleep.
>
> Fixes: 9d5612ca165a ("drm/i915/gt: Defer enabling the breadcrumb interrupt to after submission")
> Closes: https://gitlab.freedesktop.org/drm/intel/issues/10026
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Andrzej Hajda <andrzej.hajda@intel.com>
> Cc: <stable@vger.kernel.org> # v5.12+
> Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Completely forgot this one.
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Regards
Andrzej
> ---
> drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 15 +++++++--------
> 1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
> index d650beb8ed22f..20b9b04ec1e0b 100644
> --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
> @@ -263,8 +263,13 @@ static void signal_irq_work(struct irq_work *work)
> i915_request_put(rq);
> }
>
> + /* Lazy irq enabling after HW submission */
> if (!READ_ONCE(b->irq_armed) && !list_empty(&b->signalers))
> intel_breadcrumbs_arm_irq(b);
> +
> + /* And confirm that we still want irqs enabled before we yield */
> + if (READ_ONCE(b->irq_armed) && !atomic_read(&b->active))
> + intel_breadcrumbs_disarm_irq(b);
> }
>
> struct intel_breadcrumbs *
> @@ -315,13 +320,7 @@ void __intel_breadcrumbs_park(struct intel_breadcrumbs *b)
> return;
>
> /* Kick the work once more to drain the signalers, and disarm the irq */
> - irq_work_sync(&b->irq_work);
> - while (READ_ONCE(b->irq_armed) && !atomic_read(&b->active)) {
> - local_irq_disable();
> - signal_irq_work(&b->irq_work);
> - local_irq_enable();
> - cond_resched();
> - }
> + irq_work_queue(&b->irq_work);
> }
>
> void intel_breadcrumbs_free(struct kref *kref)
> @@ -404,7 +403,7 @@ static void insert_breadcrumb(struct i915_request *rq)
> * the request as it may have completed and raised the interrupt as
> * we were attaching it into the lists.
> */
> - if (!b->irq_armed || __i915_request_is_complete(rq))
> + if (!READ_ONCE(b->irq_armed) || __i915_request_is_complete(rq))
> irq_work_queue(&b->irq_work);
> }
>
next prev parent reply other threads:[~2024-05-09 12:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-23 16:23 [PATCH] drm/i915/gt: Disarm breadcrumbs if engines are already idle Janusz Krzysztofik
2024-04-26 16:13 ` Nirmoy Das
2024-04-29 9:20 ` Janusz Krzysztofik
2024-05-09 12:41 ` Andrzej Hajda [this message]
2024-05-14 12:46 ` Andi Shyti
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