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a3adcce795
The current virDomainObjListPtr object stores domain objects in an array. This means that to find a particular objects requires O(n) time, and more critically acquiring O(n) mutex locks. The new impl replaces the array with a virHashTable, keyed off UUID. Finding a object based on UUID is now O(1) time, and only requires a single mutex lock. Finding by name/id is unchanged in complexity. In changing this, all code which iterates over the array had to be updated to use a hash table iterator function callback. Several of the functions which were identically duplicating across all drivers were pulled into domain_conf.c * src/conf/domain_conf.h, src/conf/domain_conf.c: Change virDomainObjListPtr to use virHashTable. Add a initializer method virDomainObjListInit, and rename virDomainObjListFree to virDomainObjListDeinit, since its not actually freeing the container, only its contents. Also add some convenient methods virDomainObjListGetInactiveNames, virDomainObjListGetActiveIDs and virDomainObjListNumOfDomains which can be used to implement the correspondingly named public API entry points in drivers * src/libvirt_private.syms: Export new methods from domain_conf.h * src/lxc/lxc_driver.c, src/opennebula/one_driver.c, src/openvz/openvz_conf.c, src/openvz/openvz_driver.c, src/qemu/qemu_driver.c, src/test/test_driver.c, src/uml/uml_driver.c, src/vbox/vbox_tmpl.c: Update all code to deal with hash tables instead of arrays for domains |
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| .. | ||
| README | ||
| vbox_CAPI_v2_2.h | ||
| vbox_CAPI_v3_0.h | ||
| vbox_driver.c | ||
| vbox_driver.h | ||
| vbox_tmpl.c | ||
| vbox_V2_2.c | ||
| vbox_V3_0.c | ||
| vbox_XPCOMCGlue.c | ||
| vbox_XPCOMCGlue.h | ||
Explanation about the how multi-version support
for VirtualBox libvirt driver is implemented.
Since VirtualBox adds multiple new features for each release, it is but
natural that the C API which VirtualBox exposes is volatile across
versions and thus needs a good mechanism to handle multiple versions
during runtime. The solution was something like this:
Firstly the file structure is as below:
vbox_CAPI_v2_2.h
vbox_XPCOMCGlue.h
vbox_XPCOMCGlue.c
These files are C API/glue code files directly taken from the
VirtualBox OSE source and is needed for C API to work as expected.
vbox_driver.h
vbox_driver.c
These files have the main logic for registering the virtualbox driver
with libvirt.
vbox_V2_2.c
The file which has version dependent changes and includes the template
file for given below for all of its functionality.
vbox_tmpl.c
The file where all the real driver implementation code exists.
Now there would be a vbox_V*.c file (for eg: vbox_V2_2.c for V2.2) for
each major virtualbox version which would do some preprocessor magic
and include the template file (vbox_tmpl.c) in it for the functionality
it offers.