2c4affd57e
https://bugzilla.redhat.com/show_bug.cgi?id=1480668 QEMU has this new feature memory-backend-file.discard-data=yes which is a nifty optimization. Basically, when qemu is quitting or on memory hotplug it calls munmap() and close() on the file that is backing the memory. However, this does not mean kernel won't stop touching that part of memory. It still might. With this feature enabled we tell kernel: "we don't need this memory nor data stored in it". This makes kernel drop the memory immediately without trying to sync memory with the mapped file. Unfortunately, this cannot be turned on by default because we can't be sure when users really don't care about what happens to data after qemu dies. So it has to be opt-in. As usual, there are three places where one can configure memory attributes. This patch adds the feature to all of them. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Ján Tomko <jtomko@redhat.com>
Libvirt API for virtualization
Libvirt provides a portable, long term stable C API for managing the virtualization technologies provided by many operating systems. It includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER Hypervisor.
For some of these hypervisors, it provides a stateful management daemon which runs on the virtualization host allowing access to the API both by non-privileged local users and remote users.
Layered packages provide bindings of the libvirt C API into other languages including Python, Perl, PHP, Go, Java, OCaml, as well as mappings into object systems such as GObject, CIM and SNMP.
Further information about the libvirt project can be found on the website:
License
The libvirt C API is distributed under the terms of GNU Lesser General
Public License, version 2.1 (or later). Some parts of the code that are
not part of the C library may have the more restrictive GNU General
Public License, version 2.1 (or later). See the files COPYING.LESSER
and COPYING for full license terms & conditions.
Installation
Libvirt uses the GNU Autotools build system, so in general can be built and installed with the usual commands. For example, to build in a manner that is suitable for installing as root, use:
$ ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make
$ sudo make install
While to build & install as an unprivileged user
$ ./configure --prefix=$HOME/usr
$ make
$ make install
The libvirt code relies on a large number of 3rd party libraries. These will
be detected during execution of the configure script and a summary printed
which lists any missing (optional) dependencies.
Contributing
The libvirt project welcomes contributions in many ways. For most components the best way to contribute is to send patches to the primary development mailing list. Further guidance on this can be found on the website:
https://libvirt.org/contribute.html
Contact
The libvirt project has two primary mailing lists:
- libvirt-users@redhat.com (for user discussions)
- libvir-list@redhat.com (for development only)
Further details on contacting the project are available on the website: