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=-13.1 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=ham 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 98718C2D0E2 for ; Tue, 22 Sep 2020 23:11:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5CC5D221F0 for ; Tue, 22 Sep 2020 23:11:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600816313; bh=O0EqAQUcxVlJ7D3OFsCNRhUqCVDPp2JvHYgx47vVf4g=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=0fbTts6rO0x8H9cNk90Y5I47Nfh3kycDlm+jDbSYeIZKu5oV4CXARgUEzqYSm7Awc PSf4NhPsovQ/Cazd5cDhnBMq1A82AaAkUIFPvRgEcFRM2OHugzKrL6Op50AGcTJfy8 BiZ+EaknSVixefBYhg4znOlRdpTeWTHHFy4GImug= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726722AbgIVXLw (ORCPT ); Tue, 22 Sep 2020 19:11:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:36070 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726448AbgIVXLv (ORCPT ); Tue, 22 Sep 2020 19:11:51 -0400 Received: from paulmck-ThinkPad-P72.home (unknown [50.45.173.55]) (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 EB922221EF; Tue, 22 Sep 2020 23:11:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600816311; bh=O0EqAQUcxVlJ7D3OFsCNRhUqCVDPp2JvHYgx47vVf4g=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=JwGpufvJH9jIfpqR7ZaBC2A1k10LRr7324SlLWau7auL4JB0hYizSQseYnasHd51e 5BjmYGGC85cz0EQm890QH9H9I94HxUSDB6XSvMPGj0sZW33YU4j7tXsXqdMDVkbwmT dC0R1XbanOTYO8sjf494n0UK/oocSq+GvvH9UXNM= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id B8A1B3522CEC; Tue, 22 Sep 2020 16:11:50 -0700 (PDT) Date: Tue, 22 Sep 2020 16:11:50 -0700 From: "Paul E. McKenney" To: Frederic Weisbecker Cc: LKML , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Josh Triplett Subject: Re: [RFC PATCH 01/12] rcu: Implement rcu_segcblist_is_offloaded() config dependent Message-ID: <20200922231150.GK29330@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200921124351.24035-1-frederic@kernel.org> <20200921124351.24035-2-frederic@kernel.org> <20200922002732.GT29330@paulmck-ThinkPad-P72> <20200922214326.GF5217@lenoir> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200922214326.GF5217@lenoir> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 22, 2020 at 11:43:26PM +0200, Frederic Weisbecker wrote: > On Mon, Sep 21, 2020 at 05:27:32PM -0700, Paul E. McKenney wrote: > > On Mon, Sep 21, 2020 at 02:43:40PM +0200, Frederic Weisbecker wrote: > > > This simplify the usage of this API and avoid checking the kernel > > > config from the callers. > > > > > > Suggested-by: Paul E. McKenney > > > Signed-off-by: Frederic Weisbecker > > > Cc: Paul E. McKenney > > > Cc: Josh Triplett > > > Cc: Steven Rostedt > > > Cc: Mathieu Desnoyers > > > Cc: Lai Jiangshan > > > Cc: Joel Fernandes > > > > Nice cleanup! I clearly should have done it this way to start with. > > > > Any reason I shouldn't pull this into -rcu right now? > > I think that very one can be applied indeed. Very well! I had to hand-apply it due to recent -rcu thrash, and as usual I could not resist wordsmithing the commit log. Please let me know if I messed anything up. Thanx, Paul ------------------------------------------------------------------------ commit 99a2a9b00b1f44019e5667cdbd44b8eb82e9f0a9 Author: Frederic Weisbecker Date: Mon Sep 21 14:43:40 2020 +0200 rcu: Implement rcu_segcblist_is_offloaded() config dependent This commit simplifies the use of the rcu_segcblist_is_offloaded() API so that its callers no longer need to check the RCU_NOCB_CPU Kconfig option. Note that rcu_segcblist_is_offloaded() is defined in the header file, which means that the generated code should be just as efficient as before. Suggested-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Cc: Paul E. McKenney Cc: Josh Triplett Cc: Steven Rostedt Cc: Mathieu Desnoyers Cc: Lai Jiangshan Cc: Joel Fernandes Signed-off-by: Paul E. McKenney diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index 5c293af..492262b 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -62,7 +62,7 @@ static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp) /* Is the specified rcu_segcblist offloaded? */ static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp) { - return rsclp->offloaded; + return IS_ENABLED(CONFIG_RCU_NOCB_CPU) && rsclp->offloaded; } /* diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 2424e2a..6d9ec8e 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1609,8 +1609,7 @@ static bool __note_gp_changes(struct rcu_node *rnp, struct rcu_data *rdp) { bool ret = false; bool need_qs; - const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); raw_lockdep_assert_held_rcu_node(rnp); @@ -2054,8 +2053,7 @@ static void rcu_gp_cleanup(void) needgp = true; } /* Advance CBs to reduce false positives below. */ - offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); if ((offloaded || !rcu_accelerate_cbs(rnp, rdp)) && needgp) { WRITE_ONCE(rcu_state.gp_flags, RCU_GP_FLAG_INIT); WRITE_ONCE(rcu_state.gp_req_activity, jiffies); @@ -2254,8 +2252,7 @@ rcu_report_qs_rdp(struct rcu_data *rdp) unsigned long flags; unsigned long mask; bool needwake = false; - const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); struct rcu_node *rnp; WARN_ON_ONCE(rdp->cpu != smp_processor_id()); @@ -2423,8 +2420,7 @@ static void rcu_do_batch(struct rcu_data *rdp) { int div; unsigned long flags; - const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); struct rcu_head *rhp; struct rcu_cblist rcl = RCU_CBLIST_INITIALIZER(rcl); long bl, count; @@ -2681,8 +2677,7 @@ static __latent_entropy void rcu_core(void) unsigned long flags; struct rcu_data *rdp = raw_cpu_ptr(&rcu_data); struct rcu_node *rnp = rdp->mynode; - const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); if (cpu_is_offline(smp_processor_id())) return; @@ -2984,8 +2979,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func) rcu_segcblist_n_cbs(&rdp->cblist)); /* Go handle any RCU core processing required. */ - if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - unlikely(rcu_segcblist_is_offloaded(&rdp->cblist))) { + if (unlikely(rcu_segcblist_is_offloaded(&rdp->cblist))) { __call_rcu_nocb_wake(rdp, was_alldone, flags); /* unlocks */ } else { __call_rcu_core(rdp, head, flags); @@ -3739,8 +3733,7 @@ static int rcu_pending(int user) /* Has RCU gone idle with this CPU needing another grace period? */ if (!gp_in_progress && rcu_segcblist_is_enabled(&rdp->cblist) && - (!IS_ENABLED(CONFIG_RCU_NOCB_CPU) || - !rcu_segcblist_is_offloaded(&rdp->cblist)) && + !rcu_segcblist_is_offloaded(&rdp->cblist) && !rcu_segcblist_restempty(&rdp->cblist, RCU_NEXT_READY_TAIL)) return 1;