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 5192BECAAA1 for ; Sat, 17 Sep 2022 19:58:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229548AbiIQT6Q (ORCPT ); Sat, 17 Sep 2022 15:58:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229436AbiIQT6O (ORCPT ); Sat, 17 Sep 2022 15:58:14 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B10F2C67F; Sat, 17 Sep 2022 12:58:13 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D2010B80CC9; Sat, 17 Sep 2022 19:58:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B4D5C433D6; Sat, 17 Sep 2022 19:58:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663444690; bh=3vm2XB41ub78dBlNNb37rRU70W7xPM2xBMBgKKbUlNw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CfCkVFuQPXNGuaEbmLc5yUACzeeEu8F03wnO2jzUcQ6UWyex3xJhZKcWRceQvI2M5 rtRafpGR8GYTtlMeyAWQUiO0i+NpBNCQN52c8SEiBvlnSR6IEocJ9D5eS7ybJC0qQU eubecWN2Xs2n6GjCgjvwJ194XGVcpAlTLVh7zEDdXTIzk12iupUvuM0QdrtZVs4526 XaVUovMzczDbVKho2G1+JXJgz5nELHVljKOuM8ySAE/h0l3DpVdqDNYVUxVm1OStyL XiddZxPiWSKCpEEV+cW+T1g0xlABU865r0l/+V9ekvjdRxSR6QrLTr5JEDWigIP4cn m0Fn2J31m1LvQ== Date: Sat, 17 Sep 2022 21:58:07 +0200 From: Frederic Weisbecker To: "Joel Fernandes (Google)" Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, rushikesh.s.kadam@intel.com, urezki@gmail.com, neeraj.iitr10@gmail.com, paulmck@kernel.org, rostedt@goodmis.org Subject: Re: [PATCH rcu/next 3/3] rcu: Call trace_rcu_callback() also for bypass queuing (v2) Message-ID: <20220917195807.GA39579@lothringen> References: <20220917164200.511783-1-joel@joelfernandes.org> <20220917164200.511783-4-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220917164200.511783-4-joel@joelfernandes.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 17, 2022 at 04:42:00PM +0000, Joel Fernandes (Google) wrote: > @@ -2809,17 +2825,15 @@ void call_rcu(struct rcu_head *head, rcu_callback_t func) > } > > check_cb_ovld(rdp); > - if (rcu_nocb_try_bypass(rdp, head, &was_alldone, flags)) > + > + if (rcu_nocb_try_bypass(rdp, head, &was_alldone, flags)) { > + __trace_rcu_callback(head, rdp); > return; // Enqueued onto ->nocb_bypass, so just leave. > + } I think the bypass enqueues should be treated differently. Either with extending the current trace_rcu_callback/trace_rcu_kvfree_callback (might break tools) or with creating a new trace_rcu_callback_bypass()/trace_rcu_kvfree_callback_bypass(). Those could later be paired with a trace_rcu_bypass_flush(). Thanks. > + > // If no-CBs CPU gets here, rcu_nocb_try_bypass() acquired ->nocb_lock. > rcu_segcblist_enqueue(&rdp->cblist, head); > - if (__is_kvfree_rcu_offset((unsigned long)func)) > - trace_rcu_kvfree_callback(rcu_state.name, head, > - (unsigned long)func, > - rcu_segcblist_n_cbs(&rdp->cblist)); > - else > - trace_rcu_callback(rcu_state.name, head, > - rcu_segcblist_n_cbs(&rdp->cblist)); > + __trace_rcu_callback(head, rdp); > > trace_rcu_segcb_stats(&rdp->cblist, TPS("SegCBQueued")); > > -- > 2.37.3.968.ga6b4b080e4-goog >