Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2999540AbdD1VPy (ORCPT ); Fri, 28 Apr 2017 17:15:54 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:56484 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2999406AbdD1VPr (ORCPT ); Fri, 28 Apr 2017 17:15:47 -0400 Date: Fri, 28 Apr 2017 14:15:46 -0700 From: "Paul E. McKenney" To: nicolas.pitre@linaro.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH RFC tip/core/rcu] Make SRCU be once again optional Reply-To: paulmck@linux.vnet.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17042821-0052-0000-0000-000001EB26F3 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006991; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000208; SDB=6.00853745; UDB=6.00422208; IPR=6.00632686; BA=6.00005316; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015228; XFM=3.00000014; UTC=2017-04-28 21:15:45 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17042821-0053-0000-0000-0000504C7B78 Message-Id: <20170428211546.GA23590@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-28_14:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1704280258 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1882 Lines: 54 Hello, Nicolas! Saw the TTY write up LWN and figured I should send this your way. It should be worth about 2K compared to current -next, which gave up the 2K compared to v4.10. So really getting things back to where they were. My current plan is to push this into v4.13. Thanx, Paul ------------------------------------------------------------------------ commit e01ef0529ed548c1b30206058c2b5eecbbc07998 Author: Paul E. McKenney Date: Fri Apr 28 13:53:04 2017 -0700 srcu: Make SRCU be once again optional Commit d160a727c40e ("srcu: Make SRCU be built by default") in response to build errors, which were caused by code that included srcu.h despite !SRCU. However, srcutiny.o is almost 2K of code, which is not insignificant for those attempting to run the Linux kernel on IoT devices. This commit therefore makes SRCU be once again optional, and adjusts srcu.h to allow error-free inclusion in !SRCU kernel builds. Signed-off-by: Paul E. McKenney Cc: Nicolas Pitre diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 167ad8831aaf..c0143fe2e39d 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -62,7 +62,7 @@ int init_srcu_struct(struct srcu_struct *sp); #include #elif defined(CONFIG_CLASSIC_SRCU) #include -#else +#elif defined(CONFIG_SRCU) #error "Unknown SRCU implementation specified to kernel configuration" #endif diff --git a/init/Kconfig b/init/Kconfig index 42a346b0df43..fe72c12e06a5 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -521,7 +521,6 @@ config RCU_EXPERT config SRCU bool - default y help This option selects the sleepable version of RCU. This version permits arbitrary sleeping or blocking within RCU read-side critical