From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B47ACCD11C2 for ; Wed, 10 Apr 2024 14:06:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 424AB10FF96; Wed, 10 Apr 2024 14:06:39 +0000 (UTC) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6782F10FF96; Wed, 10 Apr 2024 14:06:34 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 7F99C61BE9; Wed, 10 Apr 2024 14:06:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38980C433C7; Wed, 10 Apr 2024 14:06:32 +0000 (UTC) Date: Wed, 10 Apr 2024 10:09:08 -0400 From: Steven Rostedt To: Sebastian Andrzej Siewior Cc: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Thomas Gleixner , Tvrtko Ursulin Subject: Re: [PATCH 05/10] drm/i915: skip DRM_I915_LOW_LEVEL_TRACEPOINTS with NOTRACE Message-ID: <20240410100908.7d13393c@gandalf.local.home> In-Reply-To: <20240410110857.BBV2fQYP@linutronix.de> References: <20240405142737.920626-1-bigeasy@linutronix.de> <20240405142737.920626-6-bigeasy@linutronix.de> <20240408130650.6f9c1e1c@rorschach.local.home> <20240409110601.FWFqmGjM@linutronix.de> <20240409115533.7c84b283@gandalf.local.home> <20240410110857.BBV2fQYP@linutronix.de> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Wed, 10 Apr 2024 13:08:57 +0200 Sebastian Andrzej Siewior wrote: > On 2024-04-09 11:55:33 [-0400], Steven Rostedt wrote: > > I believe you need to do it in the .c file: > >=20 > > Can you try something like this? > > =20 > =E2=80=A6 > > ? =20 >=20 > I tried and nothing changed because the lowlevel config option isn't the > problem. What about I drop this and replace 4/10 from this series with > the patch below? After enabling all tracing I don't see any events in > events/i915. I don't see anything wrong with this approach. >=20 > Sebastian >=20 > --------------------->8---------------------------- =20 >=20 > From: Sebastian Andrzej Siewior > Date: Thu, 6 Dec 2018 09:52:20 +0100 > Subject: [PATCH] drm/i915: Disable tracing points on PREEMPT_RT >=20 > Luca Abeni reported this: > | BUG: scheduling while atomic: kworker/u8:2/15203/0x00000003 > | CPU: 1 PID: 15203 Comm: kworker/u8:2 Not tainted 4.19.1-rt3 #10 > | Call Trace: > | rt_spin_lock+0x3f/0x50 > | gen6_read32+0x45/0x1d0 [i915] > | g4x_get_vblank_counter+0x36/0x40 [i915] > | trace_event_raw_event_i915_pipe_update_start+0x7d/0xf0 [i915] >=20 > The tracing events use trace_i915_pipe_update_start() among other events > use functions acquire spinlock_t locks which are transformed into > sleeping locks on PREEMPT_RT. A few trace points use > intel_get_crtc_scanline(), others use ->get_vblank_counter() wich also > might acquire a sleeping locks on PREEMPT_RT. > At the time the arguments are evaluated within trace point, preemption > is disabled and so the locks must not be acquired on PREEMPT_RT. >=20 > Based on this I don't see any other way than disable trace points on > PREMPT_RT. >=20 > Reported-by: Luca Abeni > Cc: Steven Rostedt > Signed-off-by: Sebastian Andrzej Siewior > --- > drivers/gpu/drm/i915/display/intel_display_trace.h | 4 ++++ > drivers/gpu/drm/i915/i915_trace.h | 4 ++++ > 2 files changed, 8 insertions(+) >=20 > diff --git a/drivers/gpu/drm/i915/display/intel_display_trace.h b/drivers= /gpu/drm/i915/display/intel_display_trace.h > index 7862e7cefe027..e4608d855bfba 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_trace.h > +++ b/drivers/gpu/drm/i915/display/intel_display_trace.h > @@ -9,6 +9,10 @@ > #if !defined(__INTEL_DISPLAY_TRACE_H__) || defined(TRACE_HEADER_MULTI_RE= AD) > #define __INTEL_DISPLAY_TRACE_H__ > =20 > +#ifdef CONFIG_PREEMPT_RT Hmm, should these be: #if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) ? because it's not protected due to the TRACE_HEADER_MULTI_READ. -- Steve > +#define NOTRACE > +#endif > + > #include > #include > #include > diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i91= 5_trace.h > index ce1cbee1b39dd..c54653cf72c95 100644 > --- a/drivers/gpu/drm/i915/i915_trace.h > +++ b/drivers/gpu/drm/i915/i915_trace.h > @@ -6,6 +6,10 @@ > #if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ) > #define _I915_TRACE_H_ > =20 > +#ifdef CONFIG_PREEMPT_RT > +#define NOTRACE > +#endif > + > #include > #include > #include