From patchwork Sun Jun 12 02:02:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zqiang X-Patchwork-Id: 12878630 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 BFFE0C43334 for ; Sun, 12 Jun 2022 02:02:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229800AbiFLCCr (ORCPT ); Sat, 11 Jun 2022 22:02:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229781AbiFLCCq (ORCPT ); Sat, 11 Jun 2022 22:02:46 -0400 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE74D110F; Sat, 11 Jun 2022 19:02:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1654999362; x=1686535362; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=iKrCwgb9uS93jd0NsZKfGCrvtHPpYo5dR2R538MRcS8=; b=WKULbeeQbrxnQxSgbwhW5IFNydULTA8Yeja5OZlbAKLztMEGgpFxaKMd gU6pQn0HFl3fDkvsiDswGME7NsIF/VtSw1DhvJzXauet/+vpR2+6543PD Tc/QkWoadmJie6p0AQPlkMghRc76WDAcxZF8y6q5lippypI7Pm/+GC2GC SiTNMx3xWwIVBL1dF8ZW1vXjgzWpIZvSALqgNYRlXojjYhEI27GqnWq46 NICgFlaNEZ9ejTkMy5iTddZLIqtuV/vcDquiJqXF1BI8OK0i6lNFI8nt0 4+nqFeenzAj6XilPAIyrfT2+YLXd+h7JsHHBq9JmiRtxEOat93BTwxM43 g==; X-IronPort-AV: E=McAfee;i="6400,9594,10375"; a="276748766" X-IronPort-AV: E=Sophos;i="5.91,294,1647327600"; d="scan'208";a="276748766" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jun 2022 19:02:40 -0700 X-IronPort-AV: E=Sophos;i="5.91,294,1647327600"; d="scan'208";a="638955602" Received: from zq-optiplex-7090.bj.intel.com ([10.238.156.125]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jun 2022 19:02:39 -0700 From: Zqiang To: joel@joelfernandes.org, paulmck@kernel.org, frederic@kernel.org Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] refscale: Convert test_lock spinlock to raw_spinlock Date: Sun, 12 Jun 2022 10:02:25 +0800 Message-Id: <20220612020225.3098239-1-qiang1.zhang@intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org In PREEMPT_RT kernel, the spinlock are replaced by sleepable rt_mutex. in a critical section where preemption is disabled this will trigger calltrace like the following: BUG: scheduling while atomic: ref_scale_reade/76/0x00000002 Preemption disabled at: ref_lock_section+0x16/0x80 Call Trace: dump_stack_lvl+0x5b/0x82 dump_stack+0x10/0x12 __schedule_bug.cold+0x9c/0xad __schedule+0x839/0xc00 schedule_rtlock+0x22/0x40 rtlock_slowlock_locked+0x460/0x1350 rt_spin_lock+0x61/0xe0 ref_lock_section+0x29/0x80 rcu_scale_one_reader+0x52/0x60 ref_scale_reader+0x28d/0x490 kthread+0x128/0x150 ret_from_fork+0x22/0x30 Convert spinlock to raw_spinlock to fix it. Signed-off-by: Zqiang --- kernel/rcu/refscale.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c index 909644abee67..435c884c02b5 100644 --- a/kernel/rcu/refscale.c +++ b/kernel/rcu/refscale.c @@ -385,7 +385,7 @@ static struct ref_scale_ops rwsem_ops = { }; // Definitions for global spinlock -static DEFINE_SPINLOCK(test_lock); +static DEFINE_RAW_SPINLOCK(test_lock); static void ref_lock_section(const int nloops) { @@ -393,8 +393,8 @@ static void ref_lock_section(const int nloops) preempt_disable(); for (i = nloops; i >= 0; i--) { - spin_lock(&test_lock); - spin_unlock(&test_lock); + raw_spin_lock(&test_lock); + raw_spin_unlock(&test_lock); } preempt_enable(); } @@ -405,9 +405,9 @@ static void ref_lock_delay_section(const int nloops, const int udl, const int nd preempt_disable(); for (i = nloops; i >= 0; i--) { - spin_lock(&test_lock); + raw_spin_lock(&test_lock); un_delay(udl, ndl); - spin_unlock(&test_lock); + raw_spin_unlock(&test_lock); } preempt_enable(); } @@ -427,8 +427,8 @@ static void ref_lock_irq_section(const int nloops) preempt_disable(); for (i = nloops; i >= 0; i--) { - spin_lock_irqsave(&test_lock, flags); - spin_unlock_irqrestore(&test_lock, flags); + raw_spin_lock_irqsave(&test_lock, flags); + raw_spin_unlock_irqrestore(&test_lock, flags); } preempt_enable(); } @@ -440,9 +440,9 @@ static void ref_lock_irq_delay_section(const int nloops, const int udl, const in preempt_disable(); for (i = nloops; i >= 0; i--) { - spin_lock_irqsave(&test_lock, flags); + raw_spin_lock_irqsave(&test_lock, flags); un_delay(udl, ndl); - spin_unlock_irqrestore(&test_lock, flags); + raw_spin_unlock_irqrestore(&test_lock, flags); } preempt_enable(); }