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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.
89646e69ac
Right now, grabbing blockinfo always calls stat on the disk, then opens the image to determine the capacity, using a throw-away virStorageSourcePtr. This has a couple of drawbacks: 1. We are calling stat and opening a file on every invocation of the API. However, there are cases where the stats should NOT be changing between successive calls (if a domain is running, no one should be changing the physical size of a block device or raw image behind our backs; capacity of read-only files should not be changing; and we are the gateway to the block-resize command to know when the capacity of read-write files should be changing). True, we still have to use stat in some cases (a sparse raw file changes allocation if it is read-write and the amount of holes is changing, and a read-write qcow2 image stored in a file changes physical size if it was not fully pre-allocated). But for read-only images, even this should be something we can remember from the previous time, rather than repeating every call. 2. We want to enhance the power of virDomainListGetStats, by sharing code. But we already have a virStorageSourcePtr for each disk, and it would be easier to reuse the common structure than to have to worry about the one-off virDomainBlockInfoPtr. While this patch does not optimize reuse of information in point 1, it does get us closer to being able to do so; by updating a structure that survives between consecutive calls. * src/util/virstoragefile.h (_virStorageSource): Add physical, to mirror virDomainBlockInfo; rearrange fields to match public struct. (virStorageSourceCopy): Copy the new field. * src/qemu/qemu_driver.c (qemuDomainGetBlockInfo): Store into storage source, then copy to block info. Signed-off-by: Eric Blake <eblake@redhat.com> |
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| daemon | ||
| docs | ||
| examples | ||
| gnulib | ||
| include | ||
| m4 | ||
| po | ||
| src | ||
| tests | ||
| tools | ||
| .ctags | ||
| .dir-locals.el | ||
| .gitignore | ||
| .gitmodules | ||
| .mailmap | ||
| AUTHORS.in | ||
| autobuild.sh | ||
| autogen.sh | ||
| bootstrap | ||
| bootstrap.conf | ||
| cfg.mk | ||
| ChangeLog-old | ||
| config-post.h | ||
| configure.ac | ||
| COPYING | ||
| COPYING.LESSER | ||
| HACKING | ||
| libvirt-lxc.pc.in | ||
| libvirt-qemu.pc.in | ||
| libvirt.pc.in | ||
| libvirt.spec.in | ||
| Makefile.am | ||
| Makefile.nonreentrant | ||
| mingw-libvirt.spec.in | ||
| README | ||
| README-hacking | ||
| run.in | ||
| TODO | ||
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>