From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 03E491FB1; Sun, 4 Oct 2026 00:17:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791073024; cv=none; b=AK3lFYpA3mqTvuvPOnS2R0ti0wjTktVdF/u81JT9cCsbNZc2jIolMkLt1a0XnJrHbT8ELxq7tLuMpxR5Y6hxVZ8+kTqs+cClyjXCL0ty1vprOFUaLBRWhvVS1Cazgd8qC0rsvn5/2ZRTDUQmEoEHVvWHHtYrdKhEsxdCedYMZQg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791073024; c=relaxed/simple; bh=QwPx0hRDcObW7PfhIUc5+6PwUltypAH+jdVDo3Om/gE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RK1oXY/2FRaPTCrvmUZ1lXUW6+7cVTJj/Huxhv7hn/+wP8wzDFrICkzbM2Kc7MdneQhYmqBj+1GxmudvMSYKCysHQMqHcko43jgSaFPXySwhLj6SS9EIBYgSDb5e8V5z4Y2jIXBL75vOvUVmTuDym0fLwsA7Boo78P6NbFb9DEw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=U/yKHVeL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="U/yKHVeL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6E531F0089B; Sun, 4 Oct 2026 00:17:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791073022; bh=f0X55k1JjyZmnpTVYm2uh+cKq8TEASg4b9fJw48Vv8k=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To; b=U/yKHVeL8XHRcEr60nsO4bv/yZckU6MfB/7U1Ftr3bJR8xPDT2YttyctjtK0qCVef D04+Kzbq2m/UClrBSH2Ytqkc9NyYfDw96s3CCOMIZdePz3/VLsODTJLkxEhoO22tf4 VWJQnGN7xcjsdYbkyL84vRR+xARl3zzhkn1VWgLeNYlHoVJDZq9gcsh/GwqQJfbVpJ wqybdEO7RECabHL0K9JkID0fTAv93KNaGfHt/g775R3d6XuVYaaaHERUzTnZNfBGp5 nG/97tdBz1RCL2I6d9JOKbLvRE+9QqckO54Dp4XjF1LHXSb9BuSL1WPbGicktG8gqi pRD0wPFQ7i3Tg== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 7AB35CE39A4; Sat, 3 Oct 2026 17:17:02 -0700 (PDT) Date: Sat, 3 Oct 2026 17:17:02 -0700 From: "Paul E. McKenney" To: Kunwu Chan Cc: dave@stgolabs.net, josh@joshtriplett.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, joelagnelf@nvidia.com, boqun@kernel.org, urezki@gmail.com, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang@linux.dev, linux-kernel@vger.kernel.org, rcu@vger.kernel.org Subject: Re: [PATCH v2] rcuscale: add srcua scale type Message-ID: Reply-To: paulmck@kernel.org References: <20261003161720.240855-1-kunwu.chan@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261003161720.240855-1-kunwu.chan@gmail.com> On Sun, Oct 04, 2026 at 12:17:19AM +0800, Kunwu Chan wrote: > Add support for scaling atomic SRCU grace periods using > srcu_read_lock_atomic()/srcu_read_unlock_atomic() and > synchronize_srcu_atomic(). > > Suggested-by: Paul E. McKenney > Signed-off-by: Kunwu Chan Queued for testing and further review, thank you!!! Thanx, Paul > --- > Changes since v1: > - Rename srcu_atomic_ctlp to srcua and reuse srcu_ctlp for > SRCU operations, as suggested by Paul. > - Reuse the existing SRCU cleanup and completed helpers by > initializing srcu_ctlp in srcu_atomic_scale_init(). > - Add .stats using srcu_scale_stats(). > - Use "srcua" to match the existing "srcu" and "srcud" scale > type names. > - Use synchronize_srcu_atomic() for both normal and expedited > scale tests. > > v1: https://lore.kernel.org/all/20260927100359.3903688-1-kunwu.chan@gmail.com/ > Tested with kvm.sh --torture rcuscale scale_type=srcua on x86_64 and > arm64, alongside gp_exp=1 and PROVE_LOCKING=y: no warnings or lockdep > splats. > --- > kernel/rcu/rcuscale.c | 41 ++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 40 insertions(+), 1 deletion(-) > > diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c > index 1097ec15879c..b172882824ac 100644 > --- a/kernel/rcu/rcuscale.c > +++ b/kernel/rcu/rcuscale.c > @@ -293,6 +293,44 @@ static struct rcu_scale_ops srcud_ops = { > .name = "srcud" > }; > > +static struct srcu_struct srcua; > + > +static int srcu_scale_atomic_read_lock(void) > +{ > + return srcu_read_lock_atomic(srcu_ctlp); > +} > + > +static void srcu_scale_atomic_read_unlock(int idx) > +{ > + srcu_read_unlock_atomic(srcu_ctlp, idx); > +} > + > +static void srcu_scale_atomic_synchronize(void) > +{ > + synchronize_srcu_atomic(srcu_ctlp); > +} > + > +static void srcu_atomic_scale_init(void) > +{ > + srcu_ctlp = &srcua; > + init_srcu_struct_atomic(srcu_ctlp); > +} > + > +static struct rcu_scale_ops srcua_ops = { > + .ptype = SRCU_FLAVOR, > + .init = srcu_atomic_scale_init, > + .cleanup = srcu_sync_scale_cleanup, > + .readlock = srcu_scale_atomic_read_lock, > + .readunlock = srcu_scale_atomic_read_unlock, > + .get_gp_seq = srcu_scale_completed, > + .gp_diff = rcu_seq_diff, > + .exp_completed = srcu_scale_completed, > + .sync = srcu_scale_atomic_synchronize, > + .exp_sync = srcu_scale_atomic_synchronize, > + .stats = srcu_scale_stats, > + .name = "srcua" > +}; > + > #ifdef CONFIG_TASKS_RCU > > /* > @@ -1110,7 +1148,8 @@ rcu_scale_init(void) > long i; > long j; > static struct rcu_scale_ops *scale_ops[] = { > - &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS > + &rcu_ops, &srcu_ops, &srcua_ops, &srcud_ops, > + TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS > }; > > if (!torture_init_begin(scale_type, verbose)) > > base-commit: d21906b0aa1e9573cdb5e7acaca44966b9d1dcd2 > -- > 2.43.0 >