Commit-ID: e5731b584b3e521e3db6fda9cdfe10646d3413a3 Gitweb: http://git.kernel.org/tip/e5731b584b3e521e3db6fda9cdfe10646d3413a3 Author: Boqun Feng <boqun.feng@xxxxxxxxx> AuthorDate: Thu, 19 May 2016 11:42:21 +0800 Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> CommitDate: Tue, 14 Jun 2016 16:03:28 -0700 rcutorture/doc: Create initrd using dracut 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 <boqun.feng@xxxxxxxxx> Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> --- 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 4170e71..833f826 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 -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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