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eb4bf0683e7c7e12b32943151dd3e4ea23852618
During xen testing, below failure was triggered if dedup=0.
(XEN) Assertion '!preempt_count()' failed at preempt.c:37
(XEN) ----[ Xen-4.5-unstable x86_64 debug=y Not tainted ]----
(XEN) CPU: 51
(XEN) RIP: e008:[<ffff82d08011bfef>] ASSERT_NOT_IN_ATOMIC+0x22/0x53
(XEN) RFLAGS: 0000000000010286 CONTEXT: hypervisor
(XEN) rax: ffff82d080318d20 rbx: ffff8300681ea000 rcx: 0000000000000001
(XEN) rdx: 00000033bca03300 rsi: ffff8308110da000 rdi: ffff82d080286690
(XEN) rbp: ffff83043cd0ff08 rsp: ffff83043cd0ff08 r8: ffff8307d2beecb0
(XEN) r9: 000000000000000d r10: 00000000deadbeef r11: 0000000000000202
(XEN) r12: 0000000000000000 r13: 0000000000000000 r14: 0000000000000005
(XEN) r15: 0000000000000001 cr0: 0000000080050033 cr4: 00000000001526f0
(XEN) cr3: 000000005246d000 cr2: ffff880106123418
(XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: e010 cs: e008
(XEN) Xen stack trace from rsp=ffff83043cd0ff08:
(XEN) 00007cfbc32f00c7 ffff82d0802258f0 ffff880106123418 ffffea0006156e80
(XEN) ffff8800d0ab5368 00007faff4c83000 ffff8801bdea33e8 0000000000000002
(XEN) 0000000000000202 00000000deadbeef 0000000000000000 00000000000c3565
(XEN) fffffffffffffff4 ffffffff810014ca ffffffff81de1000 000000000000c356
(XEN) 00000000deadbeef 0001010000000000 ffffffff810014ca 000000000000e033
(XEN) 0000000000000202 ffff8801bdea3360 000000000000e02b 000000000000beef
(XEN) 000000000000beef 000000000000beef 000000000000beef 0000000000000033
(XEN) ffff8300681ea000 00000033bca03300 0000000000000000
(XEN) Xen call trace:
(XEN) [<ffff82d08011bfef>] ASSERT_NOT_IN_ATOMIC+0x22/0x53
(XEN) [<ffff82d0802258f0>] test_all_events+0x6/0x30
The root cause is there is an wronng
'write_unlock(&pcd_tree_rwlocks[firstbyte])' in function
tmem_try_to_evict_pgp().
Nobody will lock &pcd_tree_rwlocks if dedup=0, but the write_unlock() will be
executed anyway. This was introduced by a git commit
38c433d0c7 ("tmem: add page deduplication with
optional compression or trailing-zero-elimination")
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
#################################
__ __ _ _ ____ _ _ _
\ \/ /___ _ __ | || | | ___| _ _ _ __ ___| |_ __ _| |__ | | ___
\ // _ \ '_ \ | || |_ |___ \ _____| | | | '_ \/ __| __/ _` | '_ \| |/ _ \
/ \ __/ | | | |__ _| ___) |_____| |_| | | | \__ \ || (_| | |_) | | __/
/_/\_\___|_| |_| |_|(_)____/ \__,_|_| |_|___/\__\__,_|_.__/|_|\___|
#################################
http://www.xen.org/
What is Xen?
============
Xen is a Virtual Machine Monitor (VMM) originally developed by the
Systems Research Group of the University of Cambridge Computer
Laboratory, as part of the UK-EPSRC funded XenoServers project. Xen
is freely-distributable Open Source software, released under the GNU
GPL. Since its initial public release, Xen has grown a large
development community, spearheaded by xen.org (http://www.xen.org).
The 4.3 release offers a number of improvements, including NUMA
scheduling affinity, openvswitch integration, and defaulting to
qemu-xen rather than qemu-traditional for non-stubdom guests.
(qemu-xen is kept very close to the upstream project.) We also have a
number of updates to vTPM, and improvements to XSM and Flask to allow
greater disaggregation. Additionally, 4.3 contains a basic version of
Xen for the new ARM server architecture, both 32- and 64-bit. And as
always, there are a number of performance, stability, and security
improvements under-the hood.
This file contains some quick-start instructions to install Xen on
your system. For more information see http:/www.xen.org/ and
http://wiki.xen.org/
Quick-Start Guide
=================
First, there are a number of prerequisites for building a Xen source
release. Make sure you have all the following installed, either by
visiting the project webpage or installing a pre-built package
provided by your OS distributor:
* GCC v4.1 or later
* GNU Make
* GNU Binutils
* Development install of zlib (e.g., zlib-dev)
* Development install of Python v2.3 or later (e.g., python-dev)
* Development install of curses (e.g., libncurses-dev)
* Development install of openssl (e.g., openssl-dev)
* Development install of x11 (e.g. xorg-x11-dev)
* Development install of uuid (e.g. uuid-dev)
* Development install of yajl (e.g. libyajl-dev)
* Development install of libaio (e.g. libaio-dev) version 0.3.107 or
greater.
* Development install of GLib v2.0 (e.g. libglib2.0-dev)
* Development install of Pixman (e.g. libpixman-1-dev)
* pkg-config
* bridge-utils package (/sbin/brctl)
* iproute package (/sbin/ip)
* udev
* GNU bison and GNU flex
* GNU gettext
* 16-bit x86 assembler, loader and compiler (dev86 rpm or bin86 & bcc debs)
* ACPI ASL compiler (iasl)
In addition to the above there are a number of optional build
prerequisites. Omitting these will cause the related features to be
disabled at compile time:
* Development install of Ocaml (e.g. ocaml-nox and
ocaml-findlib). Required to build ocaml components which
includes the alternative ocaml xenstored.
* cmake (if building vtpm stub domains)
* markdown
* figlet (for generating the traditional Xen start of day banner)
Second, you need to acquire a suitable kernel for use in domain 0. If
possible you should use a kernel provided by your OS distributor. If
no suitable kernel is available from your OS distributor then refer to
http://wiki.xen.org/wiki/XenDom0Kernels for suggestions for
suitable kernels to use.
If you are looking to compile a Dom0 kernel from source, please refer to
http://wiki.xen.org/wiki/XenParavirtOps.
[NB. Unless noted otherwise, all the following steps should be
performed with root privileges.]
1. Download and untar the source tarball file. This will be a
file named xen-unstable-src.tgz, or xen-$version-src.tgz.
You can also pull the current version from the mercurial
repository at http://xenbits.xen.org/
# tar xzf xen-unstable-src.tgz
Assuming you are using the unstable tree, this will
untar into xen-unstable. The rest of the instructions
use the unstable tree as an example, substitute the
version for unstable.
2. cd to xen-unstable (or whatever you sensibly rename it to).
3. For the very first build, or if you want to destroy build trees,
perform the following steps:
# ./configure
# make world
# make install
If you want, you can run ./configure --help to see the list of
options available options when building and installing Xen.
This will create and install onto the local machine. It will build
the xen binary (xen.gz), the tools and the documentation.
You can override the destination for make install by setting DESTDIR
to some value.
4. To rebuild an existing tree without modifying the config:
# make dist
This will build and install xen, tools, and docs into the local dist/
directory.
You can override the destination for make install by setting DISTDIR
to some value.
make install and make dist differ in that make install does the
right things for your local machine (installing the appropriate
version of udev scripts, for example), but make dist includes all
versions of those scripts, so that you can copy the dist directory
to another machine and install from that distribution.
Python Runtime Libraries
========================
Xend (the Xen daemon) has the following runtime dependencies:
* Python 2.3 or later.
In some distros, the XML-aspects to the standard library
(xml.dom.minidom etc) are broken out into a separate python-xml package.
This is also required.
In more recent versions of Debian and Ubuntu the XML-aspects are included
in the base python package however (python-xml has been removed
from Debian in squeeze and from Ubuntu in intrepid).
URL: http://www.python.org/
Debian: python
* For optional SSL support, pyOpenSSL:
URL: http://pyopenssl.sourceforge.net/
Debian: python-pyopenssl
* For optional PAM support, PyPAM:
URL: http://www.pangalactic.org/PyPAM/
Debian: python-pam
* For optional XenAPI support in XM, lxml:
URL: http://lxml.de/
Debian: python-lxml
YUM: python-lxml
Intel(R) Trusted Execution Technology Support
=============================================
Intel's technology for safer computing, Intel(R) Trusted Execution Technology
(Intel(R) TXT), defines platform-level enhancements that provide the building
blocks for creating trusted platforms. For more information, see
http://www.intel.com/technology/security/.
Intel(R) TXT support is provided by the Trusted Boot (tboot) module in
conjunction with minimal logic in the Xen hypervisor.
Tboot is an open source, pre- kernel/VMM module that uses Intel(R) TXT to
perform a measured and verified launch of an OS kernel/VMM.
The Trusted Boot module is available from
http://sourceforge.net/projects/tboot. This project hosts the code in a
mercurial repo at http://tboot.sourceforge.net/hg/tboot.hg and contains
tarballs of the source. Instructions in the tboot README describe how
to modify grub.conf to use tboot to launch Xen.
There are optional targets as part of Xen's top-level makefile that will
download and build tboot: install-tboot, build-tboot, dist-tboot, clean-tboot.
These will download the latest tar file from the SourceForge site using wget,
then build/install/dist according to Xen's settings.
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