From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755053Ab3JCTjN (ORCPT ); Thu, 3 Oct 2013 15:39:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50733 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754965Ab3JCTjM (ORCPT ); Thu, 3 Oct 2013 15:39:12 -0400 Date: Thu, 3 Oct 2013 21:32:06 +0200 From: Oleg Nesterov To: "Paul E. McKenney" Cc: Peter Zijlstra , Mel Gorman , Rik van Riel , Srikar Dronamraju , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Thomas Gleixner , Steven Rostedt , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] rcu: Create rcu_sync infrastructure Message-ID: <20131003193206.GA17796@redhat.com> References: <20131002145655.361606532@infradead.org> <20131002150518.675931976@infradead.org> <20131003164117.GD5790@linux.vnet.ibm.com> <20131003184001.GM28601@twins.programming.kicks-ass.net> <20131003184719.GA11996@redhat.com> <20131003192135.GR5790@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131003192135.GR5790@linux.vnet.ibm.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/03, Paul E. McKenney wrote: > > On Thu, Oct 03, 2013 at 08:47:19PM +0200, Oleg Nesterov wrote: > > > > Yes, but... > > > > I think it would be better to start with the patch below, this way > > it would be easier a) to add the new ops (we need more anyway) and b) > > use CONFIG_PROVE_RCU to avoid the unused members even if this is > > really minor. > > I am fine with this as well, but I don't see the code that checks for > the required RCU read-side critical section. Because I believe this needs another patch ;) see below, didn't test it yet. (and yes, until I saw the patch from Peter I didn't realize we already have all necessary helpers as functions, somehow I tought that they are macros). Oleg. rcusync: add the CONFIG_PROVE_RCU checks CHANGELOG --- diff --git a/include/linux/rcusync.h b/include/linux/rcusync.h index 30c6037..aa7e9e0 100644 --- a/include/linux/rcusync.h +++ b/include/linux/rcusync.h @@ -7,6 +7,9 @@ struct rcu_sync_ops { void (*sync)(void); void (*call)(struct rcu_head *, void (*)(struct rcu_head *)); +#ifdef CONFIG_PROVE_RCU + bool (*held)(void); +#endif }; struct rcu_sync_struct { @@ -22,6 +25,9 @@ struct rcu_sync_struct { static inline bool rcu_sync_is_idle(struct rcu_sync_struct *rss) { +#ifdef CONFIG_PROVE_RCU + WARN_ON(!rss->ops->held()); +#endif return !rss->gp_state; /* GP_IDLE */ } diff --git a/kernel/rcusync.c b/kernel/rcusync.c index 1cefb83..21f191f 100644 --- a/kernel/rcusync.c +++ b/kernel/rcusync.c @@ -6,18 +6,27 @@ enum { CB_IDLE = 0, CB_PENDING, CB_REPLAY }; #define rss_lock gp_wait.lock +#ifdef CONFIG_PROVE_RCU +#define __INIT_HELD(func) .held = func, +#else +#define __INIT_HELD(func) +#endif + struct rcu_sync_ops rcu_sync_ops_array[] = { [RCU_SYNC] = { .sync = synchronize_rcu, .call = call_rcu, + __INIT_HELD(rcu_read_lock_held) }, [RCU_SCHED_SYNC] = { .sync = synchronize_sched, .call = call_rcu_sched, + __INIT_HELD(rcu_read_lock_sched_held) }, [RCU_BH_SYNC] = { .sync = synchronize_rcu_bh, .call = call_rcu_bh, + __INIT_HELD(rcu_read_lock_bh_held) }, };