From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933366AbcFOWK6 (ORCPT ); Wed, 15 Jun 2016 18:10:58 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59178 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933202AbcFOWJv (ORCPT ); Wed, 15 Jun 2016 18:09:51 -0400 X-IBM-Helo: d01dlp01.pok.ibm.com X-IBM-MailFrom: paulmck@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, Boqun Feng , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 07/14] rcutorture/doc: Create initrd using dracut Date: Wed, 15 Jun 2016 15:09:36 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20160615220924.GA7877@linux.vnet.ibm.com> References: <20160615220924.GA7877@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16061522-0040-0000-0000-000000934AF2 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16061522-0041-0000-0000-0000046D290A Message-Id: <1466028583-8780-7-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-15_13:,, 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=8.0.1-1604210000 definitions=main-1606150235 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Boqun Feng Using dracut is another way to get an initramfs for KVM-based RCU torture tests, which is more flexible than using the host's initramfs image, because modules and binaries may be added or removed via dracut command options. So add an example in the document, in case that there are some situations where host's initramfs couldn't be used. Signed-off-by: Boqun Feng Reviewed-by: Josh Triplett Signed-off-by: Paul E. McKenney --- tools/testing/selftests/rcutorture/doc/initrd.txt | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/tools/testing/selftests/rcutorture/doc/initrd.txt b/tools/testing/selftests/rcutorture/doc/initrd.txt index 4170e714f044..833f826d6ec2 100644 --- a/tools/testing/selftests/rcutorture/doc/initrd.txt +++ b/tools/testing/selftests/rcutorture/doc/initrd.txt @@ -13,6 +13,22 @@ cd initrd cpio -id < /tmp/initrd.img.zcat ------------------------------------------------------------------------ +Another way to create an initramfs image is using "dracut"[1], which is +available on many distros, however the initramfs dracut generates is a cpio +archive with another cpio archive in it, so an extra step is needed to create +the initrd directory hierarchy. + +Here are the commands to create a initrd directory for rcutorture using +dracut: + +------------------------------------------------------------------------ +dracut --no-hostonly --no-hostonly-cmdline --module "base bash shutdown" /tmp/initramfs.img +cd tools/testing/selftests/rcutorture +mkdir initrd +cd initrd +/usr/lib/dracut/skipcpio /tmp/initramfs.img | zcat | cpio -id < /tmp/initramfs.img +------------------------------------------------------------------------ + Interestingly enough, if you are running rcutorture, you don't really need userspace in many cases. Running without userspace has the advantage of allowing you to test your kernel independently of the @@ -89,3 +105,9 @@ while : do sleep 10 done +------------------------------------------------------------------------ + +References: +[1]: https://dracut.wiki.kernel.org/index.php/Main_Page +[2]: http://blog.elastocloud.org/2015/06/rapid-linux-kernel-devtest-with-qemu.html +[3]: https://www.centos.org/forums/viewtopic.php?t=51621 -- 2.5.2