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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 8FDCEC3F2CD for ; Tue, 3 Mar 2020 13:41:26 +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 6B4A120717 for ; Tue, 3 Mar 2020 13:41:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B4A120717 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E88886E8A2; Tue, 3 Mar 2020 13:41:25 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8C2A66E8A2 for ; Tue, 3 Mar 2020 13:41:24 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Mar 2020 05:41:24 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,511,1574150400"; d="scan'208";a="286990913" Received: from gaia.fi.intel.com ([10.237.72.192]) by FMSMGA003.fm.intel.com with ESMTP; 03 Mar 2020 05:41:23 -0800 Received: by gaia.fi.intel.com (Postfix, from userid 1000) id C26465C1D7C; Tue, 3 Mar 2020 15:40:07 +0200 (EET) From: Mika Kuoppala To: Chris Wilson , intel-gfx@lists.freedesktop.org In-Reply-To: <20200303130748.1416073-1-chris@chris-wilson.co.uk> References: <20200303130748.1416073-1-chris@chris-wilson.co.uk> Date: Tue, 03 Mar 2020 15:40:07 +0200 Message-ID: <871rq97e14.fsf@gaia.fi.intel.com> MIME-Version: 1.0 Subject: Re: [Intel-gfx] [PATCH] drm/i915/gt: Drop the timeline->mutex as we wait for retirement 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Chris Wilson writes: > As we have pinned the timeline (using tl->active_count), we can safely > drop the tl->mutex as we wait for what we believe to be the final > request on that timeline. This is useful for ensuring that we do not > block the engine heartbeat by hogging the kernel_context's timeline on a > dead GPU. > > References: https://gitlab.freedesktop.org/drm/intel/issues/1364 > Fixes: 058179e72e09 ("drm/i915/gt: Replace hangcheck by heartbeats") > Signed-off-by: Chris Wilson > Cc: Mika Kuoppala > --- > drivers/gpu/drm/i915/gt/intel_gt_requests.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c > index 8a5054f21bf8..436412d07689 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c > +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c > @@ -147,24 +147,31 @@ long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout) > > fence = i915_active_fence_get(&tl->last_request); > if (fence) { > + mutex_unlock(&tl->mutex); > + > timeout = dma_fence_wait_timeout(fence, > interruptible, > timeout); > dma_fence_put(fence); > + > + if (!mutex_trylock(&tl->mutex)) { If you can't take it, it must be active and for the retirement advancement we can bail out early. Or is there something else with a sampled try? > + active_count++; > + goto out_active; > + } > } > } > > if (!retire_requests(tl) || flush_submission(gt)) > active_count++; > + mutex_unlock(&tl->mutex); > > - spin_lock(&timelines->lock); > +out_active: spin_lock(&timelines->lock); > > /* Resume iteration after dropping lock */ You either fixed this comment with this patch. Or that the comment remains a highly confusing. > list_safe_reset_next(tl, tn, link); > if (atomic_dec_and_test(&tl->active_count)) > list_del(&tl->link); We have the timelines lock and the above seems safe wtithout the actual mutex. But the comment is still hauting me. -Mika > > - mutex_unlock(&tl->mutex); > > /* Defer the final release to after the spinlock */ > if (refcount_dec_and_test(&tl->kref.refcount)) { > -- > 2.25.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx