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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D822ACDB474 for ; Mon, 16 Oct 2023 15:49:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233880AbjJPPt3 (ORCPT ); Mon, 16 Oct 2023 11:49:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233922AbjJPPt2 (ORCPT ); Mon, 16 Oct 2023 11:49:28 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8831DEA for ; Mon, 16 Oct 2023 08:49:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1697471367; x=1729007367; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=9Mv8kh/CUzFcN00rxrVSrH6ocuROm3sFvBVoQRNdq8g=; b=Eo9aeNFWSKjdDAk4kP5GawCmQ0+rOeZCtOtrCri7UgCD4OBoLvbc7PX8 3avrM9G/qkLJeDFxzwZO7yw+H/rqf3+xCI+RMahbEykz3oM40y2bebagT psAyDmnrWVNU4WWvh3ZOsUKdGv7iK5bxFBfzJ2eYMXgCgxHpjl0bFkOzD FSlGo47JeQupv5MC5IhMDRkUnhM44X1EFEh7uxfSMxvhZXNGZNdcdtlwF 9QQVSaotckm3Bou+gpGbi5luZ1usRBu+TZ2qkGZpYV9kYri02Dcjm398M RIWoC0i0SoPJP+OH3exHqsYuK1UzezV97ZIPXLP2zO+zAeDNKLJpplrWw A==; X-IronPort-AV: E=McAfee;i="6600,9927,10863"; a="449773082" X-IronPort-AV: E=Sophos;i="6.03,229,1694761200"; d="scan'208";a="449773082" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Oct 2023 08:49:27 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10863"; a="790840889" X-IronPort-AV: E=Sophos;i="6.03,229,1694761200"; d="scan'208";a="790840889" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.74]) by orsmga001.jf.intel.com with SMTP; 16 Oct 2023 08:49:24 -0700 Received: by stinkbox (sSMTP sendmail emulation); Mon, 16 Oct 2023 18:49:23 +0300 Date: Mon, 16 Oct 2023 18:49:23 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Andi Shyti Cc: intel-gfx@lists.freedesktop.org, stable@vger.kernel.org Subject: Re: [Intel-gfx] [PATCH] drm/i915: Retry gtt fault when out of fence register Message-ID: References: <20231012132801.16292-1-ville.syrjala@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Patchwork-Hint: comment Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, Oct 13, 2023 at 12:53:59PM +0200, Andi Shyti wrote: > Hi Ville, > > > If we can't find a free fence register to handle a fault in the GMADR > > range just return VM_FAULT_NOPAGE without populating the PTE so that > > userspace will retry the access and trigger another fault. Eventually > > we should find a free fence and the fault will get properly handled. > > > > A further improvement idea might be to reserve a fence (or one per CPU?) > > for the express purpose of handling faults without having to retry. But > > that would require some additional work. > > > > Looks like this may have gotten broken originally by > > commit 39965b376601 ("drm/i915: don't trash the gtt when running out of fences") > > as that changed the errno to -EDEADLK which wasn't handle by the gtt > > fault code either. But later in commit 2feeb52859fc ("drm/i915/gt: Fix > > -EDEADLK handling regression") I changed it again to -ENOBUFS as -EDEADLK > > was now getting used for the ww mutex dance. So this fix only makes > > sense after that last commit. > > > > Cc: stable@vger.kernel.org > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9479 > > Fixes: 2feeb52859fc ("drm/i915/gt: Fix -EDEADLK handling regression") > > Signed-off-by: Ville Syrjälä > > Reviewed-by: Andi Shyti Thanks. Pushed to gt-next. -- Ville Syrjälä Intel