On 10/10/24 15:29, Daniel P. Berrangé wrote:
On Thu, Aug 08, 2024 at 05:38:10PM -0600, Jim Fehlig via Devel wrote:
From: Claudio Fontana <cfontana@suse.de>
Add a new VIR_DOMAIN_SAVE_PARALLEL flag to the save and restore APIs, which can be used to specify the use of multiple, parallel channels for saving a domain. The number of parallel channels can be set using the VIR_DOMAIN_SAVE_PARAM_PARALLEL_CONNECTIONS typed parameter.
Signed-off-by: Claudio Fontana <cfontana@suse.de> Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- include/libvirt/libvirt-domain.h | 13 +++++++++++++ src/libvirt-domain.c | 6 ++++++ 2 files changed, 19 insertions(+)
diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h index 4266237abe..f4bf9c3cdb 100644 --- a/include/libvirt/libvirt-domain.h +++ b/include/libvirt/libvirt-domain.h @@ -1596,6 +1596,7 @@ typedef enum { VIR_DOMAIN_SAVE_RUNNING = 1 << 1, /* Favor running over paused (Since: 0.9.5) */ VIR_DOMAIN_SAVE_PAUSED = 1 << 2, /* Favor paused over running (Since: 0.9.5) */ VIR_DOMAIN_SAVE_RESET_NVRAM = 1 << 3, /* Re-initialize NVRAM from template (Since: 8.1.0) */ + VIR_DOMAIN_SAVE_PARALLEL = 1 << 4, /* Save and restore using parallel channels (Since: 10.6.0) */ } virDomainSaveRestoreFlags;
int virDomainSave (virDomainPtr domain, @@ -1641,6 +1642,18 @@ int virDomainRestoreParams (virConnectPtr conn, */ # define VIR_DOMAIN_SAVE_PARAM_DXML "dxml"
+/** + * VIR_DOMAIN_SAVE_PARAM_PARALLEL_CONNECTIONS: + * + * this optional parameter mirrors the migration parameter + * VIR_MIGRATE_PARAM_PARALLEL_CONNECTIONS. + * + * It specifies the number of extra connections to use when transfering state. + * + * Since: 10.6.0 + */ +# define VIR_DOMAIN_SAVE_PARAM_PARALLEL_CONNECTIONS "parallel.connections"
"CONNECTIONS" is perhaps the wrong name, as that's kinda an impl
I would suggest CONNECTIONS it is the correct name.
detail. How about VIR_MIGRATE_PARAM_PARALLEL_CPUS to reflect the number of CPUs we're going to burn time on.
This is another aspect of it, but I would suggest that _this_ is much more an implementation detail (inside qemu) on how the parallel connection is actually managed. Maybe in the future there will be a pool of cpus serving this, or another optional way to serve the connections. Considering the fact that libvirt _already has_ for regular migrations {.typedParam = VIR_MIGRATE_PARAM_PARALLEL_CONNECTIONS, .param = QEMU_MIGRATION_PARAM_MULTIFD_CHANNELS, .party = QEMU_MIGRATION_SOURCE | QEMU_MIGRATION_DESTINATION}, which controls exactly the same QEMU parameter (ie the multifd-channels), using anything else than --parallel-connections is in my opinion very surprising for the users (which would know what to expect from the same command line option), and honestly simply absurd. Thanks, Claudio
+ /* See below for virDomainSaveImageXMLFlags */ char * virDomainSaveImageGetXMLDesc (virConnectPtr conn, const char *file, diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c index 5aedae1b49..32508a4ede 100644 --- a/src/libvirt-domain.c +++ b/src/libvirt-domain.c @@ -1010,6 +1010,9 @@ virDomainSaveFlags(virDomainPtr domain, const char *to, * If VIR_DOMAIN_SAVE_PARAM_FILE is not provided then a managed save is * performed (see virDomainManagedSave). * + * See VIR_DOMAIN_SAVE_PARAM_* for detailed description of accepted save + * parameters. + * * Returns 0 in case of success and -1 in case of failure. * * Since: 8.4.0 @@ -1222,6 +1225,9 @@ virDomainRestoreFlags(virConnectPtr conn, const char *from, const char *dxml, * now, VIR_DOMAIN_SAVE_PARAM_FILE is required but this requirement may * be lifted in the future. * + * See VIR_DOMAIN_SAVE_PARAM_* for detailed description of accepted + * restore parameters. + * * Returns 0 in case of success and -1 in case of failure. * * Since: 8.4.0 -- 2.35.3
With regards, Daniel