From patchwork Wed Feb 1 19:41:22 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: 6531 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 14DFB249CD for ; Wed, 1 Feb 2012 19:43:29 +0000 (UTC) Received: from mail-bk0-f52.google.com (mail-bk0-f52.google.com [209.85.214.52]) by fiordland.canonical.com (Postfix) with ESMTP id 046F5A1834C for ; Wed, 1 Feb 2012 19:43:28 +0000 (UTC) Received: by mail-bk0-f52.google.com with SMTP id r19so1858856bka.11 for ; Wed, 01 Feb 2012 11:43:28 -0800 (PST) Received: by 10.205.134.129 with SMTP id ic1mr13155739bkc.92.1328125408854; Wed, 01 Feb 2012 11:43:28 -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 10.204.130.220 with SMTP id u28cs220029bks; Wed, 1 Feb 2012 11:43:28 -0800 (PST) Received: by 10.68.211.198 with SMTP id ne6mr280191pbc.83.1328125407118; Wed, 01 Feb 2012 11:43:27 -0800 (PST) Received: from e9.ny.us.ibm.com (e9.ny.us.ibm.com. [32.97.182.139]) by mx.google.com with ESMTPS id j9si260842pbh.19.2012.02.01.11.43.26 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 01 Feb 2012 11:43:27 -0800 (PST) Received-SPF: pass (google.com: domain of paulmck@linux.vnet.ibm.com designates 32.97.182.139 as permitted sender) client-ip=32.97.182.139; Authentication-Results: mx.google.com; spf=pass (google.com: domain of paulmck@linux.vnet.ibm.com designates 32.97.182.139 as permitted sender) smtp.mail=paulmck@linux.vnet.ibm.com Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 1 Feb 2012 14:43:22 -0500 Received: from d01dlp01.pok.ibm.com (9.56.224.56) by e9.ny.us.ibm.com (192.168.1.109) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Wed, 1 Feb 2012 14:43:20 -0500 Received: from d01relay03.pok.ibm.com (d01relay03.pok.ibm.com [9.56.227.235]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id B643E38C806B; Wed, 1 Feb 2012 14:42:59 -0500 (EST) Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q11JguPP306574; Wed, 1 Feb 2012 14:42:57 -0500 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 q11Jg5M6031507; Wed, 1 Feb 2012 12:42:07 -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 q11Jg5AC031450; Wed, 1 Feb 2012 12:42:05 -0700 Received: by paulmck-ThinkPad-W500 (Postfix, from userid 1000) id 3B5CFE51F2; Wed, 1 Feb 2012 11:42:02 -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 RFC tip/core/rcu 04/41] rcu: Add diagnostic for misaligned rcu_head structures Date: Wed, 1 Feb 2012 11:41:22 -0800 Message-Id: <1328125319-5205-4-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.8 In-Reply-To: <1328125319-5205-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20120201194131.GA10028@linux.vnet.ibm.com> <1328125319-5205-1-git-send-email-paulmck@linux.vnet.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12020119-7182-0000-0000-000000A32A85 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 d0f8e64..4655f3e 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;