From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: [PATCH RFC LKMM 2/7] tools/memory-model: Refactor some RCU relations Date: Wed, 9 Jan 2019 13:07:43 -0800 Message-ID: <20190109210748.29074-2-paulmck@linux.ibm.com> References: <20190109210706.GA27268@linux.ibm.com> Return-path: In-Reply-To: <20190109210706.GA27268@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@kernel.org Cc: stern@rowland.harvard.edu, parri.andrea@gmail.com, will.deacon@arm.com, peterz@infradead.org, boqun.feng@gmail.com, npiggin@gmail.com, dhowells@redhat.com, j.alglave@ucl.ac.uk, luc.maranget@inria.fr, willy@infradead.org, "Paul E . McKenney" List-Id: linux-arch.vger.kernel.org From: Alan Stern In preparation for adding support for SRCU, refactor the definitions of rcu-fence, rcu-rscsi, rcu-link, and rb by moving the po and po? terms from the first two to the second two. An rcu-gp relation is added; it is equivalent to gp with the po and po? terms removed. This is necessary because for SRCU, we will have to use the loc relation to check that the terms at the start and end of each disjunct in the definition of rcu-fence refer to the same srcu_struct location. If these terms are hidden behind po and po?, there's no way to carry out this check. Signed-off-by: Alan Stern Signed-off-by: Paul E. McKenney Tested-by: Andrea Parri --- tools/memory-model/linux-kernel.cat | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/tools/memory-model/linux-kernel.cat b/tools/memory-model/linux-kernel.cat index ab9de9c1234b..b8e6197f05af 100644 --- a/tools/memory-model/linux-kernel.cat +++ b/tools/memory-model/linux-kernel.cat @@ -91,32 +91,37 @@ acyclic pb as propagation (*******) (* - * Effect of read-side critical section proceeds from the rcu_read_lock() - * onward on the one hand and from the rcu_read_unlock() backwards on the + * Effects of read-side critical sections proceed from the rcu_read_unlock() + * backwards on the one hand, and from the rcu_read_lock() forwards on the * other hand. + * + * In the definition of rcu-fence below, the po term at the left-hand side + * of each disjunct and the po? term at the right-hand end have been factored + * out. They have been moved into the definitions of rcu-link and rb. *) -let rcu-rscsi = po ; rcu-rscs^-1 ; po? +let rcu-gp = [Sync-rcu] (* Compare with gp *) +let rcu-rscsi = rcu-rscs^-1 (* * The synchronize_rcu() strong fence is special in that it can order not * one but two non-rf relations, but only in conjunction with an RCU * read-side critical section. *) -let rcu-link = hb* ; pb* ; prop +let rcu-link = po? ; hb* ; pb* ; prop ; po (* * Any sequence containing at least as many grace periods as RCU read-side * critical sections (joined by rcu-link) acts as a generalized strong fence. *) -let rec rcu-fence = gp | - (gp ; rcu-link ; rcu-rscsi) | - (rcu-rscsi ; rcu-link ; gp) | - (gp ; rcu-link ; rcu-fence ; rcu-link ; rcu-rscsi) | - (rcu-rscsi ; rcu-link ; rcu-fence ; rcu-link ; gp) | +let rec rcu-fence = rcu-gp | + (rcu-gp ; rcu-link ; rcu-rscsi) | + (rcu-rscsi ; rcu-link ; rcu-gp) | + (rcu-gp ; rcu-link ; rcu-fence ; rcu-link ; rcu-rscsi) | + (rcu-rscsi ; rcu-link ; rcu-fence ; rcu-link ; rcu-gp) | (rcu-fence ; rcu-link ; rcu-fence) (* rb orders instructions just as pb does *) -let rb = prop ; rcu-fence ; hb* ; pb* +let rb = prop ; po ; rcu-fence ; po? ; hb* ; pb* irreflexive rb as rcu -- 2.17.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:39810 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726154AbfAIVH6 (ORCPT ); Wed, 9 Jan 2019 16:07:58 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id x09Kn16w044836 for ; Wed, 9 Jan 2019 16:07:57 -0500 Received: from e12.ny.us.ibm.com (e12.ny.us.ibm.com [129.33.205.202]) by mx0a-001b2d01.pphosted.com with ESMTP id 2pwpxh4pky-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 09 Jan 2019 16:07:56 -0500 Received: from localhost by e12.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 9 Jan 2019 21:07:55 -0000 From: "Paul E. McKenney" Subject: [PATCH RFC LKMM 2/7] tools/memory-model: Refactor some RCU relations Date: Wed, 9 Jan 2019 13:07:43 -0800 In-Reply-To: <20190109210706.GA27268@linux.ibm.com> References: <20190109210706.GA27268@linux.ibm.com> Message-ID: <20190109210748.29074-2-paulmck@linux.ibm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@kernel.org Cc: stern@rowland.harvard.edu, parri.andrea@gmail.com, will.deacon@arm.com, peterz@infradead.org, boqun.feng@gmail.com, npiggin@gmail.com, dhowells@redhat.com, j.alglave@ucl.ac.uk, luc.maranget@inria.fr, willy@infradead.org, "Paul E . McKenney" Message-ID: <20190109210743.jCbvMSYXzgm4LokWW1VPG5YJrM2x0SGp6HtI2ENViAk@z> From: Alan Stern In preparation for adding support for SRCU, refactor the definitions of rcu-fence, rcu-rscsi, rcu-link, and rb by moving the po and po? terms from the first two to the second two. An rcu-gp relation is added; it is equivalent to gp with the po and po? terms removed. This is necessary because for SRCU, we will have to use the loc relation to check that the terms at the start and end of each disjunct in the definition of rcu-fence refer to the same srcu_struct location. If these terms are hidden behind po and po?, there's no way to carry out this check. Signed-off-by: Alan Stern Signed-off-by: Paul E. McKenney Tested-by: Andrea Parri --- tools/memory-model/linux-kernel.cat | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/tools/memory-model/linux-kernel.cat b/tools/memory-model/linux-kernel.cat index ab9de9c1234b..b8e6197f05af 100644 --- a/tools/memory-model/linux-kernel.cat +++ b/tools/memory-model/linux-kernel.cat @@ -91,32 +91,37 @@ acyclic pb as propagation (*******) (* - * Effect of read-side critical section proceeds from the rcu_read_lock() - * onward on the one hand and from the rcu_read_unlock() backwards on the + * Effects of read-side critical sections proceed from the rcu_read_unlock() + * backwards on the one hand, and from the rcu_read_lock() forwards on the * other hand. + * + * In the definition of rcu-fence below, the po term at the left-hand side + * of each disjunct and the po? term at the right-hand end have been factored + * out. They have been moved into the definitions of rcu-link and rb. *) -let rcu-rscsi = po ; rcu-rscs^-1 ; po? +let rcu-gp = [Sync-rcu] (* Compare with gp *) +let rcu-rscsi = rcu-rscs^-1 (* * The synchronize_rcu() strong fence is special in that it can order not * one but two non-rf relations, but only in conjunction with an RCU * read-side critical section. *) -let rcu-link = hb* ; pb* ; prop +let rcu-link = po? ; hb* ; pb* ; prop ; po (* * Any sequence containing at least as many grace periods as RCU read-side * critical sections (joined by rcu-link) acts as a generalized strong fence. *) -let rec rcu-fence = gp | - (gp ; rcu-link ; rcu-rscsi) | - (rcu-rscsi ; rcu-link ; gp) | - (gp ; rcu-link ; rcu-fence ; rcu-link ; rcu-rscsi) | - (rcu-rscsi ; rcu-link ; rcu-fence ; rcu-link ; gp) | +let rec rcu-fence = rcu-gp | + (rcu-gp ; rcu-link ; rcu-rscsi) | + (rcu-rscsi ; rcu-link ; rcu-gp) | + (rcu-gp ; rcu-link ; rcu-fence ; rcu-link ; rcu-rscsi) | + (rcu-rscsi ; rcu-link ; rcu-fence ; rcu-link ; rcu-gp) | (rcu-fence ; rcu-link ; rcu-fence) (* rb orders instructions just as pb does *) -let rb = prop ; rcu-fence ; hb* ; pb* +let rb = prop ; po ; rcu-fence ; po? ; hb* ; pb* irreflexive rb as rcu -- 2.17.1