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 F0B8AC433EF for ; Tue, 22 Mar 2022 13:17:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235321AbiCVNS6 (ORCPT ); Tue, 22 Mar 2022 09:18:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235269AbiCVNSq (ORCPT ); Tue, 22 Mar 2022 09:18:46 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C45FD64712; Tue, 22 Mar 2022 06:17:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1647955038; x=1679491038; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=dAcxrMAdYGWi8WSTjO6a3fMaU21hxA6oy2q2nk6xPPc=; b=dZs5xOzUCW1TpjMvTbS9UluzpgVIuu5dS4IVYTVQVUIkR7kZeLk1+xdn hv0Ya2wwNO4IZop33ERGUfYTjI+DQxF3y7X0BbBqIQ3rjtND0Hh402u8f rleea1KXPdeAY2WyuYcPRZCyz6EeOrjOrgH/DB+KIyWeqt34taim7xDjN kRFJ7tBJPYC0KYa+KQ2MJ2JfqHeyQNuh6tdkg4MyaOp/Ne8RS0akYoqbV RU2OlQLJGBuHBJex/XcsRim1R4MhPZS2yaLDnEyzsfbUF5HHjoxuO0ykE XHmrJJ6T7OO2a0msl/Wup4kBVtQ8yN0u9Gx/rs36+LRCcQktJpRzKUR+R w==; X-IronPort-AV: E=McAfee;i="6200,9189,10293"; a="237755597" X-IronPort-AV: E=Sophos;i="5.90,201,1643702400"; d="scan'208";a="237755597" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Mar 2022 06:17:17 -0700 X-IronPort-AV: E=Sophos;i="5.90,201,1643702400"; d="scan'208";a="543686431" Received: from zq-optiplex-7090.bj.intel.com ([10.238.156.125]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Mar 2022 06:17:16 -0700 From: Zqiang To: paulmck@kernel.org, frederic@kernel.org Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 0/2] rcu: Deoffload rdp if rcuop/rcuog kthreads spawn failed Date: Tue, 22 Mar 2022 21:17:51 +0800 Message-Id: <20220322131753.1680329-1-qiang1.zhang@intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When CONFIG_RCU_NOCB_CPU is enabled and 'rcu_nocbs' is set, the rcuop and rcuog kthreads is created. however the rcuop or rcuog kthreads creation may fail, if failed, deoffload the offloaded rdp. --- v1->v2: Invert the locking dependency order between rcu_state.barrier_mutex and hotplug lock. Holding nocb_gp_kthread_mutex, ensure that the nocb_gp_kthread exists. v2->v3: Adjust the position of the nocb_gp_kthread_mutex, in rdp_gp->nocb_gp_kthread check upper lock nocb_gp_kthread_mutex. Do the locking order change in a separate patch. v3->v4: Protect SEGCBLIST_KTHREAD_CB flags clear with rcu_nocb lock. Zqiang(2): rcu: Call rcu_nocb_rdp_deoffload() directly after rcuog/op kthreads spawn failed rcu: Invert the locking dependency order between rcu_state.barrier_mutex and hotplug lock kernel/rcu/tree_nocb.h | 85 ++++++++++++++++++++++++++++++++---------- 1 file changed, 65 insertions(+), 20 deletions(-) -- 2.25.1