From patchwork Fri Jun 28 12:58:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 13716101 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 824CAC3064D for ; Fri, 28 Jun 2024 13:06:17 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5CBD710EC4B; Fri, 28 Jun 2024 13:06:12 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.b="sEPb0Bzg"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="JElxYQ3V"; dkim-atps=neutral Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4537B10EC3E; Fri, 28 Jun 2024 13:06:08 +0000 (UTC) From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1719579966; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nDRiXqdZUrRJml/pYgW8ySo5l4Ui2vAz5hfNGnk7Y4c=; b=sEPb0BzgacOLGuCfvr9v06KSPJZY0r4ZCoJEGvBJzkDDKcdpPVxQmbMdvpUu/agvCnuLhO qlCfn4YCub0f+ooZ1rRkRNOS6ODcwglLU2uu5gjswAYoJOUj1RZKgQVcDhSMbnOdpMX4jH CylvA07zOWuNHFcKvU6VBYlLM+o+Er9ogPYTNK4Sq/MzWne5qDXrlgewy6wtMtTF4XvZVS LyiSa85302BMViHOEOLXs0FnkuOGmizSGBKtPtr919WYZrksFpP1QA6HNVcCAnoyNwkFUk IiSc6EEmuybBlLzD1QrwDMYAfoJDMV/jtkET/h12DItJS/eAS/BM3VquBlgS7w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1719579966; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nDRiXqdZUrRJml/pYgW8ySo5l4Ui2vAz5hfNGnk7Y4c=; b=JElxYQ3V8n3Et8CMETNtqe4Yyv8+4yEwnDCtKGkOSOPHAk0/eGh/IXeuxPMPOihmAC9UKK 5qMQ2aS9DHIqIoDw== To: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org Cc: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Thomas Gleixner , Tvrtko Ursulin , Sebastian Andrzej Siewior , Tvrtko Ursulin Subject: [PATCH v3 3/8] drm/i915: Don't check for atomic context on PREEMPT_RT Date: Fri, 28 Jun 2024 14:58:02 +0200 Message-ID: <20240628130601.1772849-4-bigeasy@linutronix.de> In-Reply-To: <20240628130601.1772849-1-bigeasy@linutronix.de> References: <20240628130601.1772849-1-bigeasy@linutronix.de> MIME-Version: 1.0 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" The !in_atomic() check in _wait_for_atomic() triggers on PREEMPT_RT because the uncore::lock is a spinlock_t and does not disable preemption or interrupts. Changing the uncore:lock to a raw_spinlock_t doubles the worst case latency on an otherwise idle testbox during testing. Ignore _WAIT_FOR_ATOMIC_CHECK() on PREEMPT_RT. Reviewed-by: Tvrtko Ursulin Link: https://lore.kernel.org/all/20211006164628.s2mtsdd2jdbfyf7g@linutronix.de/ Signed-off-by: Sebastian Andrzej Siewior --- drivers/gpu/drm/i915/i915_utils.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h index 06ec6ceb61d57..12cbf04990182 100644 --- a/drivers/gpu/drm/i915/i915_utils.h +++ b/drivers/gpu/drm/i915/i915_utils.h @@ -273,8 +273,13 @@ wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms) (Wmax)) #define wait_for(COND, MS) _wait_for((COND), (MS) * 1000, 10, 1000) -/* If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. */ -#if defined(CONFIG_DRM_I915_DEBUG) && defined(CONFIG_PREEMPT_COUNT) +/* + * If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. + * On PREEMPT_RT the context isn't becoming atomic because it is used in an + * interrupt handler or because a spinlock_t is acquired. This leads to + * warnings which don't occur otherwise and therefore the check is disabled. + */ +#if defined(CONFIG_DRM_I915_DEBUG) && defined(CONFIG_PREEMPT_COUNT) && !defined(CONFIG_PREEMPT_RT) # define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) WARN_ON_ONCE((ATOMIC) && !in_atomic()) #else # define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) do { } while (0)