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=-8.6 required=3.0 tests=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 02624ECE588 for ; Tue, 15 Oct 2019 10:57:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4E9221928 for ; Tue, 15 Oct 2019 10:57:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571137043; bh=DOazOHrhGYjtGI/8yMNyg8pFGwNff+cPJ7RtuF6t/OE=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=KX6Y7f3/tm/i5mJG1pGgh8+dUwJR/9YihlbNjpY7+CeGkwkAjHOHMF3Kn5TErQtZL XhWFVMyQI/n7SdsonrEepBRyyZ8c6PFZpKG2w6bruTbl+BgJ2fR/pvuJHfZvEfjV+t WGqooB2Oyo6yGGfBwHXatxWDfNsWdy6NX3ZHTQxA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731603AbfJOK5U (ORCPT ); Tue, 15 Oct 2019 06:57:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:50138 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726054AbfJOK5U (ORCPT ); Tue, 15 Oct 2019 06:57:20 -0400 Received: from paulmck-ThinkPad-P72 (unknown [76.14.14.11]) (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 2CBDC217F9; Tue, 15 Oct 2019 10:57:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571137038; bh=DOazOHrhGYjtGI/8yMNyg8pFGwNff+cPJ7RtuF6t/OE=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=rqLhKWnfSJARtfDtPPblsKgNaT72Z6D7E+ms1Uml6ipZCCwA7Ooy3fbtrHmRPIV0+ 4+9rbRTY7TAQiZ9me3FbwCyTOoNXAZQcrDVbtM/llRDMs8vGItMXuPCHZakSvl6+OD XXhg+zQAa7dD0//J6aH4UrwtJ7gVeMmSV5XHr4ic= Date: Tue, 15 Oct 2019 03:57:16 -0700 From: "Paul E. McKenney" To: Lai Jiangshan Cc: Lai Jiangshan , Joel Fernandes , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Ingo Molnar , Luis Chamberlain , Kees Cook , David Sterba , Mike Rapoport , Yafang Shao , Marco Elver , rcu@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2] rcu: make PREEMPT_RCU to be a decoration of TREE_RCU Message-ID: <20191015105716.GR2689@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20191015020023.GO2689@paulmck-ThinkPad-P72> <20191015025559.829-1-laijs@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191015025559.829-1-laijs@linux.alibaba.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Oct 15, 2019 at 02:55:57AM +0000, Lai Jiangshan wrote: > Currently PREEMPT_RCU and TREE_RCU are "contrary" configs > when they can't be both on. But PREEMPT_RCU is actually a kind > of TREE_RCU in the implementation. It seams to be appropriate > to make PREEMPT_RCU to be a decorative option of TREE_RCU. > > Signed-off-by: Lai Jiangshan > Signed-off-by: Lai Jiangshan > Reviewed-by: Joel Fernandes (Google) Applied for further review and testing, thank you both! Thanx, Paul > --- > Changed from v1: > Rebased on -rcu "dev" branch > include/linux/rcupdate.h | 4 ++-- > include/trace/events/rcu.h | 4 ++-- > kernel/rcu/Kconfig | 13 +++++++------ > kernel/rcu/Makefile | 1 - > kernel/rcu/rcu.h | 2 +- > kernel/rcu/update.c | 2 +- > kernel/sysctl.c | 2 +- > 7 files changed, 14 insertions(+), 14 deletions(-) > > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > index c6351314cbe6..4dcf46985922 100644 > --- a/include/linux/rcupdate.h > +++ b/include/linux/rcupdate.h > @@ -167,7 +167,7 @@ do { \ > * TREE_RCU and rcu_barrier_() primitives in TINY_RCU. > */ > > -#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) > +#if defined(CONFIG_TREE_RCU) > #include > #elif defined(CONFIG_TINY_RCU) > #include > @@ -585,7 +585,7 @@ do { \ > * read-side critical section that would block in a !PREEMPT kernel. > * But if you want the full story, read on! > * > - * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU), > + * In non-preemptible RCU implementations (pure TREE_RCU and TINY_RCU), > * it is illegal to block while in an RCU read-side critical section. > * In preemptible RCU implementations (PREEMPT_RCU) in CONFIG_PREEMPTION > * kernel builds, RCU read-side critical sections may be preempted, > diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h > index 35a384ec78b5..5e49b06e8104 100644 > --- a/include/trace/events/rcu.h > +++ b/include/trace/events/rcu.h > @@ -41,7 +41,7 @@ TRACE_EVENT(rcu_utilization, > TP_printk("%s", __entry->s) > ); > > -#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) > +#if defined(CONFIG_TREE_RCU) > > /* > * Tracepoint for grace-period events. Takes a string identifying the > @@ -432,7 +432,7 @@ TRACE_EVENT_RCU(rcu_fqs, > __entry->cpu, __entry->qsevent) > ); > > -#endif /* #if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) */ > +#endif /* #if defined(CONFIG_TREE_RCU) */ > > /* > * Tracepoint for dyntick-idle entry/exit events. These take a string > diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig > index 7644eda17d62..0303934e6ef0 100644 > --- a/kernel/rcu/Kconfig > +++ b/kernel/rcu/Kconfig > @@ -7,7 +7,7 @@ menu "RCU Subsystem" > > config TREE_RCU > bool > - default y if !PREEMPTION && SMP > + default y if SMP > help > This option selects the RCU implementation that is > designed for very large SMP system with hundreds or > @@ -17,6 +17,7 @@ config TREE_RCU > config PREEMPT_RCU > bool > default y if PREEMPTION > + select TREE_RCU > help > This option selects the RCU implementation that is > designed for very large SMP systems with hundreds or > @@ -78,7 +79,7 @@ config TASKS_RCU > user-mode execution as quiescent states. > > config RCU_STALL_COMMON > - def_bool ( TREE_RCU || PREEMPT_RCU ) > + def_bool TREE_RCU > help > This option enables RCU CPU stall code that is common between > the TINY and TREE variants of RCU. The purpose is to allow > @@ -86,13 +87,13 @@ config RCU_STALL_COMMON > making these warnings mandatory for the tree variants. > > config RCU_NEED_SEGCBLIST > - def_bool ( TREE_RCU || PREEMPT_RCU || TREE_SRCU ) > + def_bool ( TREE_RCU || TREE_SRCU ) > > config RCU_FANOUT > int "Tree-based hierarchical RCU fanout value" > range 2 64 if 64BIT > range 2 32 if !64BIT > - depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT > + depends on TREE_RCU && RCU_EXPERT > default 64 if 64BIT > default 32 if !64BIT > help > @@ -112,7 +113,7 @@ config RCU_FANOUT_LEAF > int "Tree-based hierarchical RCU leaf-level fanout value" > range 2 64 if 64BIT > range 2 32 if !64BIT > - depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT > + depends on TREE_RCU && RCU_EXPERT > default 16 > help > This option controls the leaf-level fanout of hierarchical > @@ -187,7 +188,7 @@ config RCU_BOOST_DELAY > > config RCU_NOCB_CPU > bool "Offload RCU callback processing from boot-selected CPUs" > - depends on TREE_RCU || PREEMPT_RCU > + depends on TREE_RCU > depends on RCU_EXPERT || NO_HZ_FULL > default n > help > diff --git a/kernel/rcu/Makefile b/kernel/rcu/Makefile > index 020e8b6a644b..82d5fba48b2f 100644 > --- a/kernel/rcu/Makefile > +++ b/kernel/rcu/Makefile > @@ -9,6 +9,5 @@ obj-$(CONFIG_TINY_SRCU) += srcutiny.o > obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o > obj-$(CONFIG_RCU_PERF_TEST) += rcuperf.o > obj-$(CONFIG_TREE_RCU) += tree.o > -obj-$(CONFIG_PREEMPT_RCU) += tree.o > obj-$(CONFIG_TINY_RCU) += tiny.o > obj-$(CONFIG_RCU_NEED_SEGCBLIST) += rcu_segcblist.o > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h > index c30a1f7dbd15..a7ab2a023dd3 100644 > --- a/kernel/rcu/rcu.h > +++ b/kernel/rcu/rcu.h > @@ -427,7 +427,7 @@ enum rcutorture_type { > INVALID_RCU_FLAVOR > }; > > -#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) > +#if defined(CONFIG_TREE_RCU) > void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags, > unsigned long *gp_seq); > void do_trace_rcu_torture_read(const char *rcutorturename, > diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c > index 196487762b96..2f529470cafa 100644 > --- a/kernel/rcu/update.c > +++ b/kernel/rcu/update.c > @@ -437,7 +437,7 @@ struct debug_obj_descr rcuhead_debug_descr = { > EXPORT_SYMBOL_GPL(rcuhead_debug_descr); > #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ > > -#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) || defined(CONFIG_RCU_TRACE) > +#if defined(CONFIG_TREE_RCU) || defined(CONFIG_RCU_TRACE) > void do_trace_rcu_torture_read(const char *rcutorturename, struct rcu_head *rhp, > unsigned long secs, > unsigned long c_old, unsigned long c) > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 00fcea236eba..2ace158a4d72 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -1268,7 +1268,7 @@ static struct ctl_table kern_table[] = { > .proc_handler = proc_do_static_key, > }, > #endif > -#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) > +#if defined(CONFIG_TREE_RCU) > { > .procname = "panic_on_rcu_stall", > .data = &sysctl_panic_on_rcu_stall, > -- > 2.20.1 >