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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 0C52AC388F2 for ; Fri, 6 Nov 2020 19:13:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4F912151B for ; Fri, 6 Nov 2020 19:13:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604689993; bh=GlE34wY4SMh9cHwy9fY5b6a+GW8qy3H3b92CYNVkOlY=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=2Y9jZSj+6ktangHlitla6IcCyz41tS1JQgnjtIaiH2tJoFHX4Px1mL1Y1biulluv/ uiTnVpeMVmPt2wi/vJJzgTTid1fSv3TrcLir97DyTtisq9Fc2cxpRHx/SDPVuKIT3z ctFhU+5xVPklZ4PCZoAzRaarF8qkUynD9JSRcVyQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728054AbgKFTNM (ORCPT ); Fri, 6 Nov 2020 14:13:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:57916 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728122AbgKFTNM (ORCPT ); Fri, 6 Nov 2020 14:13:12 -0500 Received: from paulmck-ThinkPad-P72.home (50-39-104-11.bvtn.or.frontiernet.net [50.39.104.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4376120882; Fri, 6 Nov 2020 19:13:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604689991; bh=GlE34wY4SMh9cHwy9fY5b6a+GW8qy3H3b92CYNVkOlY=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=HsNRShLLsMj3MumqMT21spb7ze6Rkyd1cY9WfrQYFRmWpVJXVU4LVOyO5p2MliUSg AhjY++FpjhcWNOaAefQhI3o271/+oUMsG5+HP8sWZ/61GuZh4iYYinCA/lt9i7sTmA dOV9YcIfvvzVcYRkbEglEJQvAt9GjExC6MFHdHaU= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id EDBCC352097B; Fri, 6 Nov 2020 11:13:10 -0800 (PST) Date: Fri, 6 Nov 2020 11:13:10 -0800 From: "Paul E. McKenney" To: Davidlohr Bueso Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org Subject: Re: [PATCH tip/core/rcu 03/28] locktorture: Track time of last ->writeunlock() Message-ID: <20201106191310.GZ3249@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20201105234658.GA23142@paulmck-ThinkPad-P72> <20201105234719.23307-3-paulmck@kernel.org> <20201106065642.ti7mgrll7mbrndja@linux-p48b.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201106065642.ti7mgrll7mbrndja@linux-p48b.lan> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 05, 2020 at 10:56:42PM -0800, Davidlohr Bueso wrote: > On Thu, 05 Nov 2020, paulmck@kernel.org wrote: > > > From: "Paul E. McKenney" > > > > This commit adds a last_lock_release variable that tracks the time of > > the last ->writeunlock() call, which allows easier diagnosing of lock > > hangs when using a kernel debugger. > > This makes sense to have. > > Acked-by: Davidlohr Bueso Will apply, thank you! Thanx, Paul > > Cc: Davidlohr Bueso > > Signed-off-by: Paul E. McKenney > > --- > > kernel/locking/locktorture.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c > > index 62d215b..316531d 100644 > > --- a/kernel/locking/locktorture.c > > +++ b/kernel/locking/locktorture.c > > @@ -60,6 +60,7 @@ static struct task_struct **reader_tasks; > > > > static bool lock_is_write_held; > > static bool lock_is_read_held; > > +static unsigned long last_lock_release; > > > > struct lock_stress_stats { > > long n_lock_fail; > > @@ -632,6 +633,7 @@ static int lock_torture_writer(void *arg) > > lwsp->n_lock_acquired++; > > cxt.cur_ops->write_delay(&rand); > > lock_is_write_held = false; > > + WRITE_ONCE(last_lock_release, jiffies); > > cxt.cur_ops->writeunlock(); > > > > stutter_wait("lock_torture_writer"); > > -- > > 2.9.5 > >