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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 9FC18C433DF for ; Thu, 20 Aug 2020 08:32:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6976A207FB for ; Thu, 20 Aug 2020 08:32:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597912344; bh=7tGfaT5ZhW3kt+YoSCwJaxfo3wd1TzYGk6O+OIrjs0o=; h=Subject:To:Cc:From:Date:List-ID:From; b=Yb9y9QwI7dJqRu4YW9A0dnda112mhS/aPkWjI4f+esOV4nzlFzHuQ5B9EIz0sFoeR 6SDm2NfNwLydlF9/OWiDSnQBODeRE3fNyfWy/lH0vDBpfMpJetjGuxJjtSxvQPC1wK RqU2mDmy9+qRhcywF2ddHrFVCsOhAGHX3PO7LL1Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726799AbgHTIcW (ORCPT ); Thu, 20 Aug 2020 04:32:22 -0400 Received: from forward2-smtp.messagingengine.com ([66.111.4.226]:43185 "EHLO forward2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726772AbgHTIcI (ORCPT ); Thu, 20 Aug 2020 04:32:08 -0400 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailforward.nyi.internal (Postfix) with ESMTP id 7F4791941F6A; Thu, 20 Aug 2020 04:31:02 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute1.internal (MEProxy); Thu, 20 Aug 2020 04:31:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=fH83AD wf7jissYr88NZVIki2e1fMJsDlbMy8wXPiaPw=; b=lHaIM6bLlZgIcOIBZglMzD pnYcmeXLK2voYsTrBsTNtrtwG6954REoeak99MsBQWNE2i6BdvQp+PsTg/ebuuMG a9JwnDMaozuH+HX47wtPFAdSvkTUNDovKQJJOtLYaKKPaZZGnceJscHKnX7RtV7L OsTq6c1nNulAz48WEQqqgz5plDLQctdAp1HqidiR60fZWSndvGABNyviUmDDDvAk MOrmwjlD4QUR5lJ3QPMgLdBftIB5N2H+DbCf2jalvgSfw/REy5KGcLzqE+k/7AG9 etrli6isT/9Npbqviy4gGZEzvppWTLXcAcBQdzj1c+rBdzWP3ejnH9ISGAuxsY+g == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduiedruddutddgtddvucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvffhfffkgggtgfesthekredttd dtlfenucfhrhhomhepoehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhr gheqnecuggftrfgrthhtvghrnhepkefhhfefgfefheeffedugeeuvddvvefggffftdduue ejhffhgfevuedtvddtjefgnecuffhomhgrihhnpehfrhgvvgguvghskhhtohhprdhorhhg necukfhppeekfedrkeeirdekledruddtjeenucevlhhushhtvghrufhiiigvpedtnecurf grrhgrmhepmhgrihhlfhhrohhmpehgrhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id 235553280064; Thu, 20 Aug 2020 04:31:02 -0400 (EDT) Subject: FAILED: patch "[PATCH] drm/i915: Skip signaling a signaled request" failed to apply to 5.8-stable tree To: chris@chris-wilson.co.uk, stable@vger.kernel.org, tvrtko.ursulin@intel.com, venkata.ramana.nayana@intel.com Cc: From: Date: Thu, 20 Aug 2020 10:31:22 +0200 Message-ID: <15979122821518@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.8-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 1d9221e9d395c8c80d99d002bea3c9b6dd192d6a Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 13 Jul 2020 15:16:36 +0100 Subject: [PATCH] drm/i915: Skip signaling a signaled request Preempt-to-busy introduces various fascinating complications in that the requests may complete as we are unsubmitting them from HW. As they may then signal after unsubmission, we may find ourselves having to cleanup the signaling request from within the signaling callback. This causes us to recurse onto the same i915_request.lock. However, if the request is already signaled (as it will be before we enter the signal callbacks), we know we can skip the signaling of that request during submission, neatly evading the spinlock recursion. unsubmit(ve.rq0) # timeslice expiration or other preemption -> virtual_submit_request(ve.rq0) dma_fence_signal(ve.rq0) # request completed before preemption ack -> submit_notify(ve.rq1) -> virtual_submit_request(ve.rq1) # sees that we have completed ve.rq0 -> __i915_request_submit(ve.rq0) [ 264.210142] BUG: spinlock recursion on CPU#2, sample_multi_tr/2093 [ 264.210150] lock: 0xffff9efd6ac55080, .magic: dead4ead, .owner: sample_multi_tr/2093, .owner_cpu: 2 [ 264.210155] CPU: 2 PID: 2093 Comm: sample_multi_tr Tainted: G U [ 264.210158] Hardware name: Intel Corporation CoffeeLake Client Platform/CoffeeLake S UDIMM RVP, BIOS CNLSFWR1.R00.X212.B01.1909060036 09/06/2019 [ 264.210160] Call Trace: [ 264.210167] dump_stack+0x98/0xda [ 264.210174] spin_dump.cold+0x24/0x3c [ 264.210178] do_raw_spin_lock+0x9a/0xd0 [ 264.210184] _raw_spin_lock_nested+0x6a/0x70 [ 264.210314] __i915_request_submit+0x10a/0x3c0 [i915] [ 264.210415] virtual_submit_request+0x9b/0x380 [i915] [ 264.210516] submit_notify+0xaf/0x14c [i915] [ 264.210602] __i915_sw_fence_complete+0x8a/0x230 [i915] [ 264.210692] i915_sw_fence_complete+0x2d/0x40 [i915] [ 264.210762] __dma_i915_sw_fence_wake+0x19/0x30 [i915] [ 264.210767] dma_fence_signal_locked+0xb1/0x1c0 [ 264.210772] dma_fence_signal+0x29/0x50 [ 264.210871] i915_request_wait+0x5cb/0x830 [i915] [ 264.210876] ? dma_resv_get_fences_rcu+0x294/0x5d0 [ 264.210974] i915_gem_object_wait_fence+0x2f/0x40 [i915] [ 264.211084] i915_gem_object_wait+0xce/0x400 [i915] [ 264.211178] i915_gem_wait_ioctl+0xff/0x290 [i915] Fixes: 22b7a426bbe1 ("drm/i915/execlists: Preempt-to-busy") References: 6d06779e8672 ("drm/i915: Load balancing across a virtual engine") Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: "Nayana, Venkata Ramana" Cc: # v5.4+ Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20200713141636.29326-1-chris@chris-wilson.co.uk diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c index d907d538176e..91786310c114 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c @@ -314,13 +314,18 @@ bool i915_request_enable_breadcrumb(struct i915_request *rq) { lockdep_assert_held(&rq->lock); + if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags)) + return true; + if (test_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags)) { struct intel_breadcrumbs *b = &rq->engine->breadcrumbs; struct intel_context *ce = rq->context; struct list_head *pos; spin_lock(&b->irq_lock); - GEM_BUG_ON(test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags)); + + if (test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags)) + goto unlock; if (!__intel_breadcrumbs_arm_irq(b)) goto unlock; diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 3bb7320249ae..0b2fe55e6194 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -560,22 +560,25 @@ bool __i915_request_submit(struct i915_request *request) engine->serial++; result = true; -xfer: /* We may be recursing from the signal callback of another i915 fence */ - spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING); - +xfer: if (!test_and_set_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags)) { list_move_tail(&request->sched.link, &engine->active.requests); clear_bit(I915_FENCE_FLAG_PQUEUE, &request->fence.flags); - __notify_execute_cb(request); } - GEM_BUG_ON(!llist_empty(&request->execute_cb)); - if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags) && - !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &request->fence.flags) && - !i915_request_enable_breadcrumb(request)) - intel_engine_signal_breadcrumbs(engine); + /* We may be recursing from the signal callback of another i915 fence */ + if (!i915_request_signaled(request)) { + spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING); + + __notify_execute_cb(request); + if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, + &request->fence.flags) && + !i915_request_enable_breadcrumb(request)) + intel_engine_signal_breadcrumbs(engine); - spin_unlock(&request->lock); + spin_unlock(&request->lock); + GEM_BUG_ON(!llist_empty(&request->execute_cb)); + } return result; }