From patchwork Sat Feb 4 01:44:39 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 6606 Return-Path: X-Original-To: patchwork@peony.canonical.com Delivered-To: patchwork@peony.canonical.com Received: from fiordland.canonical.com (fiordland.canonical.com [91.189.94.145]) by peony.canonical.com (Postfix) with ESMTP id 4DC9323E92 for ; Sat, 4 Feb 2012 01:45:38 +0000 (UTC) Received: from mail-iy0-f180.google.com (mail-iy0-f180.google.com [209.85.210.180]) by fiordland.canonical.com (Postfix) with ESMTP id 16E21A180C7 for ; Sat, 4 Feb 2012 01:45:37 +0000 (UTC) Received: by mail-iy0-f180.google.com with SMTP id z7so7596471iab.11 for ; Fri, 03 Feb 2012 17:45:37 -0800 (PST) Received: by 10.50.202.67 with SMTP id kg3mr11202578igc.13.1328319937834; Fri, 03 Feb 2012 17:45:37 -0800 (PST) X-Forwarded-To: linaro-patchwork@canonical.com X-Forwarded-For: patch@linaro.org linaro-patchwork@canonical.com Delivered-To: patches@linaro.org Received: by 10.231.169.210 with SMTP id a18cs33781ibz; Fri, 3 Feb 2012 17:45:37 -0800 (PST) Received: by 10.68.74.138 with SMTP id t10mr22238582pbv.126.1328319936828; Fri, 03 Feb 2012 17:45:36 -0800 (PST) Received: from e32.co.us.ibm.com (e32.co.us.ibm.com. [32.97.110.150]) by mx.google.com with ESMTPS id o4si10805163pbq.39.2012.02.03.17.45.36 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 03 Feb 2012 17:45:36 -0800 (PST) Received-SPF: pass (google.com: domain of paulmck@linux.vnet.ibm.com designates 32.97.110.150 as permitted sender) client-ip=32.97.110.150; Authentication-Results: mx.google.com; spf=pass (google.com: domain of paulmck@linux.vnet.ibm.com designates 32.97.110.150 as permitted sender) smtp.mail=paulmck@linux.vnet.ibm.com Received: from /spool/local by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 3 Feb 2012 18:45:35 -0700 Received: from d03dlp03.boulder.ibm.com (9.17.202.179) by e32.co.us.ibm.com (192.168.1.132) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Fri, 3 Feb 2012 18:45:33 -0700 Received: from d03relay03.boulder.ibm.com (d03relay03.boulder.ibm.com [9.17.195.228]) by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id 2631019D804F; Fri, 3 Feb 2012 18:45:30 -0700 (MST) Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d03relay03.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q141jW4O170112; Fri, 3 Feb 2012 18:45:32 -0700 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q141jP66013116; Fri, 3 Feb 2012 18:45:31 -0700 Received: from paulmck-ThinkPad-W500 ([9.47.24.98]) by d03av01.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id q141jPSG013083; Fri, 3 Feb 2012 18:45:25 -0700 Received: by paulmck-ThinkPad-W500 (Postfix, from userid 1000) id C011FE51F9; Fri, 3 Feb 2012 17:45:24 -0800 (PST) From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com, patches@linaro.org, "Paul E. McKenney" , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 04/47] rcu: Add diagnostic for misaligned rcu_head structures Date: Fri, 3 Feb 2012 17:44:39 -0800 Message-Id: <1328319922-30828-4-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.8 In-Reply-To: <1328319922-30828-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20120204014452.GA29811@linux.vnet.ibm.com> <1328319922-30828-1-git-send-email-paulmck@linux.vnet.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12020401-3270-0000-0000-000003B921BF From: "Paul E. McKenney" The push for energy efficiency will require that RCU tag rcu_head structures to indicate whether or not their invocation is time critical. This tagging is best carried out in the bottom bits of the ->next pointers in the rcu_head structures. This tagging requires that the rcu_head structures be properly aligned, so this commit adds the required diagnostics. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 3cf713a..570f753 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1707,6 +1707,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), unsigned long flags; struct rcu_data *rdp; + WARN_ON_ONCE((unsigned long)head & 0x3); /* Misaligned rcu_head! */ debug_rcu_head_queue(head); head->func = func; head->next = NULL;