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 X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1DB5C4338F for ; Tue, 17 Aug 2021 16:49:35 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 98B3660EBC for ; Tue, 17 Aug 2021 16:49:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 98B3660EBC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 860386E1F9; Tue, 17 Aug 2021 16:49:34 +0000 (UTC) Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTPS id EE2D16E1F3; Tue, 17 Aug 2021 16:49:32 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10079"; a="213023384" X-IronPort-AV: E=Sophos;i="5.84,329,1620716400"; d="scan'208";a="213023384" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Aug 2021 09:49:32 -0700 X-IronPort-AV: E=Sophos;i="5.84,329,1620716400"; d="scan'208";a="510541221" Received: from jons-linux-dev-box.fm.intel.com (HELO jons-linux-dev-box) ([10.1.27.20]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Aug 2021 09:49:32 -0700 Date: Tue, 17 Aug 2021 09:44:19 -0700 From: Matthew Brost To: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, daniel.vetter@ffwll.ch Message-ID: <20210817164417.GA30732@jons-linux-dev-box> References: <20210816135139.10060-1-matthew.brost@intel.com> <20210816135139.10060-9-matthew.brost@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Subject: Re: [Intel-gfx] [PATCH 08/22] drm/i915/guc: Don't enable scheduling on a banned context, guc_id invalid, not registered 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 Tue, Aug 17, 2021 at 11:47:53AM +0200, Daniel Vetter wrote: > On Mon, Aug 16, 2021 at 06:51:25AM -0700, Matthew Brost wrote: > > When unblocking a context, do not enable scheduling if the context is > > banned, guc_id invalid, or not registered. > > > > Fixes: 62eaf0ae217d ("drm/i915/guc: Support request cancellation") > > Signed-off-by: Matthew Brost > > Cc: > > --- > > drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > > index c3b7bf7319dd..353899634fa8 100644 > > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > > @@ -1579,6 +1579,9 @@ static void guc_context_unblock(struct intel_context *ce) > > spin_lock_irqsave(&ce->guc_state.lock, flags); > > > > if (unlikely(submission_disabled(guc) || > > + intel_context_is_banned(ce) || > > + context_guc_id_invalid(ce) || > > + !lrc_desc_registered(guc, ce->guc_id) || > > !intel_context_is_pinned(ce) || > > context_pending_disable(ce) || > > context_blocked(ce) > 1)) { > > I think this entire if condition here is screaming that our intel_context > state machinery for guc is way too complex, and on the wrong side of > incomprehensible. > > Also some of these check state outside of the context, and we don't seem > to hold spinlocks for those, or anything else. > > I general I have no idea which of these are defensive programming and > cannot ever happen, and which actually can happen. There's for sure way > too many races going on given that this is all context-local stuff. A lot of this is guarding against a full GT reset while trying to cancel a request. Full GT resets make everything really hard and in pratice should never really happen because the GuC does per engine / context resets. Unfortunately IGTs do weird things like turn off per engine / contexts resets and full GT reset the only way to recover so the IGTs can will expose all the races around GT reset, especially when we run IGTs a pre-prod HW that tends to hang for whatever reason. Matt > -Daniel > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch