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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 B4C8EC07E9C for ; Tue, 6 Jul 2021 12:23:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B91B6221E for ; Tue, 6 Jul 2021 12:23:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236677AbhGFMYI (ORCPT ); Tue, 6 Jul 2021 08:24:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:42590 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232289AbhGFLbz (ORCPT ); Tue, 6 Jul 2021 07:31:55 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 263F161C66; Tue, 6 Jul 2021 11:22:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625570559; bh=jH8NKxFTKwNu/qUdPjPesAKZszR0sQ/EmNDNJP5FCcs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BG+xCv6bsUOBEQ4UiEf7oK7LhqgPQ/afvPkOEQ3bbuI6pZiFpfBpnpPMW/moJNgvn DnNXFNZVemsK/6ULieEVOF499GPiaSOo4XyXCwr6speDQ9LY+kDjax+/K1tl/kRpTS S0Oq2f4rVQPW7d1dXQO1J6+4t661LNMd4APdvWFNkkbRDiMwWvaXxoQKNXWaYvzS4y YG7o52jwCFHOwLSg5jQYzKIdQoS+UWT8ECTjoJ/ZJoo+ylu+3AfijXXbT7ZfSCMW9O luU52zTOn0utKXdGhqJAcqFS2HpqI3YTi9s97qm1Q9osswMnmVviJN3JoVLreycxfF Bn5s6Rcn570qw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrey Grodzovsky , =?UTF-8?q?Christian=20K=C3=B6nig?= , Sasha Levin , dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 5.10 027/137] drm/scheduler: Fix hang when sched_entity released Date: Tue, 6 Jul 2021 07:20:13 -0400 Message-Id: <20210706112203.2062605-27-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210706112203.2062605-1-sashal@kernel.org> References: <20210706112203.2062605-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrey Grodzovsky [ Upstream commit c61cdbdbffc169dc7f1e6fe94dfffaf574fe672a ] Problem: If scheduler is already stopped by the time sched_entity is released and entity's job_queue not empty I encountred a hang in drm_sched_entity_flush. This is because drm_sched_entity_is_idle never becomes false. Fix: In drm_sched_fini detach all sched_entities from the scheduler's run queues. This will satisfy drm_sched_entity_is_idle. Also wakeup all those processes stuck in sched_entity flushing as the scheduler main thread which wakes them up is stopped by now. v2: Reverse order of drm_sched_rq_remove_entity and marking s_entity as stopped to prevent reinserion back to rq due to race. v3: Drop drm_sched_rq_remove_entity, only modify entity->stopped and check for it in drm_sched_entity_is_idle Signed-off-by: Andrey Grodzovsky Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20210512142648.666476-14-andrey.grodzovsky@amd.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/scheduler/sched_entity.c | 3 ++- drivers/gpu/drm/scheduler/sched_main.c | 24 ++++++++++++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index 146380118962..2006cc057f99 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -113,7 +113,8 @@ static bool drm_sched_entity_is_idle(struct drm_sched_entity *entity) rmb(); /* for list_empty to work without lock */ if (list_empty(&entity->list) || - spsc_queue_count(&entity->job_queue) == 0) + spsc_queue_count(&entity->job_queue) == 0 || + entity->stopped) return true; return false; diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index 7111e0f527b0..b6c2757c3d83 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -887,9 +887,33 @@ EXPORT_SYMBOL(drm_sched_init); */ void drm_sched_fini(struct drm_gpu_scheduler *sched) { + struct drm_sched_entity *s_entity; + int i; + if (sched->thread) kthread_stop(sched->thread); + for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) { + struct drm_sched_rq *rq = &sched->sched_rq[i]; + + if (!rq) + continue; + + spin_lock(&rq->lock); + list_for_each_entry(s_entity, &rq->entities, list) + /* + * Prevents reinsertion and marks job_queue as idle, + * it will removed from rq in drm_sched_entity_fini + * eventually + */ + s_entity->stopped = true; + spin_unlock(&rq->lock); + + } + + /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */ + wake_up_all(&sched->job_scheduled); + /* Confirm no work left behind accessing device structures */ cancel_delayed_work_sync(&sched->work_tdr); -- 2.30.2 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=-16.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 88354C07E96 for ; Tue, 6 Jul 2021 11:22:42 +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 59FBE61D13 for ; Tue, 6 Jul 2021 11:22:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59FBE61D13 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BB13E6E3F0; Tue, 6 Jul 2021 11:22:41 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id EF47B6E3EF for ; Tue, 6 Jul 2021 11:22:39 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 263F161C66; Tue, 6 Jul 2021 11:22:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625570559; bh=jH8NKxFTKwNu/qUdPjPesAKZszR0sQ/EmNDNJP5FCcs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BG+xCv6bsUOBEQ4UiEf7oK7LhqgPQ/afvPkOEQ3bbuI6pZiFpfBpnpPMW/moJNgvn DnNXFNZVemsK/6ULieEVOF499GPiaSOo4XyXCwr6speDQ9LY+kDjax+/K1tl/kRpTS S0Oq2f4rVQPW7d1dXQO1J6+4t661LNMd4APdvWFNkkbRDiMwWvaXxoQKNXWaYvzS4y YG7o52jwCFHOwLSg5jQYzKIdQoS+UWT8ECTjoJ/ZJoo+ylu+3AfijXXbT7ZfSCMW9O luU52zTOn0utKXdGhqJAcqFS2HpqI3YTi9s97qm1Q9osswMnmVviJN3JoVLreycxfF Bn5s6Rcn570qw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 027/137] drm/scheduler: Fix hang when sched_entity released Date: Tue, 6 Jul 2021 07:20:13 -0400 Message-Id: <20210706112203.2062605-27-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210706112203.2062605-1-sashal@kernel.org> References: <20210706112203.2062605-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sasha Levin , =?UTF-8?q?Christian=20K=C3=B6nig?= , dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Andrey Grodzovsky [ Upstream commit c61cdbdbffc169dc7f1e6fe94dfffaf574fe672a ] Problem: If scheduler is already stopped by the time sched_entity is released and entity's job_queue not empty I encountred a hang in drm_sched_entity_flush. This is because drm_sched_entity_is_idle never becomes false. Fix: In drm_sched_fini detach all sched_entities from the scheduler's run queues. This will satisfy drm_sched_entity_is_idle. Also wakeup all those processes stuck in sched_entity flushing as the scheduler main thread which wakes them up is stopped by now. v2: Reverse order of drm_sched_rq_remove_entity and marking s_entity as stopped to prevent reinserion back to rq due to race. v3: Drop drm_sched_rq_remove_entity, only modify entity->stopped and check for it in drm_sched_entity_is_idle Signed-off-by: Andrey Grodzovsky Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20210512142648.666476-14-andrey.grodzovsky@amd.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/scheduler/sched_entity.c | 3 ++- drivers/gpu/drm/scheduler/sched_main.c | 24 ++++++++++++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index 146380118962..2006cc057f99 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -113,7 +113,8 @@ static bool drm_sched_entity_is_idle(struct drm_sched_entity *entity) rmb(); /* for list_empty to work without lock */ if (list_empty(&entity->list) || - spsc_queue_count(&entity->job_queue) == 0) + spsc_queue_count(&entity->job_queue) == 0 || + entity->stopped) return true; return false; diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index 7111e0f527b0..b6c2757c3d83 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -887,9 +887,33 @@ EXPORT_SYMBOL(drm_sched_init); */ void drm_sched_fini(struct drm_gpu_scheduler *sched) { + struct drm_sched_entity *s_entity; + int i; + if (sched->thread) kthread_stop(sched->thread); + for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) { + struct drm_sched_rq *rq = &sched->sched_rq[i]; + + if (!rq) + continue; + + spin_lock(&rq->lock); + list_for_each_entry(s_entity, &rq->entities, list) + /* + * Prevents reinsertion and marks job_queue as idle, + * it will removed from rq in drm_sched_entity_fini + * eventually + */ + s_entity->stopped = true; + spin_unlock(&rq->lock); + + } + + /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */ + wake_up_all(&sched->job_scheduled); + /* Confirm no work left behind accessing device structures */ cancel_delayed_work_sync(&sched->work_tdr); -- 2.30.2