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 2E669C54EE9 for ; Thu, 8 Sep 2022 12:23:57 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 437BA10EAAF; Thu, 8 Sep 2022 12:23:56 +0000 (UTC) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6A0AF10EAAF for ; Thu, 8 Sep 2022 12:23:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662639833; x=1694175833; h=message-id:date:mime-version:subject:to:references:from: in-reply-to:content-transfer-encoding; bh=pmFTTaFTqw5QMJknVKLZsfjLAaosrnLq4Rn67B1g1E0=; b=gA/DjbLKYA3kxAqhEv5buIS0UOOZbqmxIVAi94cUmKzyw1xdJi8bRnPi 76vBr/pum9Wmmz2fSCzwCp5D1mSLK/xEtvMfswRXISkmkp28AqM6A1e3N aj2qZVHfDs7FrRgchBNAmGF1Rpo6S8nULK5s/ygmJNimXSN0xDL9G0Ume XjARMVNSqOS3bgJIcgXsAFpU648IzJ+GwH29Dq1ECH7HUWJRiC5VjFn8M dUZ1BmB4zw/5tHXaUfMXCuUjzpvEm0QWrAzUqZK50S/6jishYnMM/vnGy RalCP+KgPDv8+H3WFmbp8uDHM8uGfuHjoypZm7Nk3oxyV5L55lOqZkGhK A==; X-IronPort-AV: E=McAfee;i="6500,9779,10463"; a="297955914" X-IronPort-AV: E=Sophos;i="5.93,300,1654585200"; d="scan'208";a="297955914" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Sep 2022 05:23:52 -0700 X-IronPort-AV: E=Sophos;i="5.93,300,1654585200"; d="scan'208";a="645061631" Received: from jdemps5x-mobl.ger.corp.intel.com (HELO [10.213.237.77]) ([10.213.237.77]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Sep 2022 05:23:52 -0700 Message-ID: Date: Thu, 8 Sep 2022 13:23:50 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 Content-Language: en-US To: Ville Syrjala , intel-gfx@lists.freedesktop.org References: <20220906174609.23494-1-ville.syrjala@linux.intel.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc In-Reply-To: <20220906174609.23494-1-ville.syrjala@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Intel-gfx] [PATCH] drm/i915: Kick rcu harder to free objects 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" On 06/09/2022 18:46, Ville Syrjala wrote: > From: Ville Syrjälä > > On gen3 the selftests are pretty much always tripping this: > <4> [383.822424] pci 0000:00:02.0: drm_WARN_ON(dev_priv->mm.shrink_count) > <4> [383.822546] WARNING: CPU: 2 PID: 3560 at drivers/gpu/drm/i915/i915_gem.c:1223 i915_gem_cleanup_early+0x96/0xb0 [i915] > > Looks to be due to the status page object lingering on the > purge_list. Call synchronize_rcu() ahead of it to make more > sure all objects have been freed. > > Signed-off-by: Ville Syrjälä > --- > drivers/gpu/drm/i915/i915_gem.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index 0f49ec9d494a..5b61f7ad6473 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -1098,6 +1098,7 @@ void i915_gem_drain_freed_objects(struct drm_i915_private *i915) > flush_delayed_work(&i915->bdev.wq); > rcu_barrier(); > } > + synchronize_rcu(); Looks a bit suspicious that a loop would not free all but one last rcu grace would. Definitely fixes the issue in your testing? Perhaps the fact there is a cond_resched in __i915_gem_free_objects, but then again free count should reflect the state and keep it looping in here.. Regards, Tvrtko