[libvirt] [PATCH 5/8] Public API for post-copy migration bandwidth

[Ján Tomko]

On Tue, Feb 05, 2019 at 04:23:08PM +0100, Jiri Denemark wrote:
>This patch adds a new VIR_MIGRATE_PARAM_BANDWIDTH_POSTCOPY typed
>parameter for virDomainMigrate3 and virDomainMigrateToURI3 for setting
>maximum post-copy migration bandwidth.
>
>In case the initial VIR_MIGRATE_PARAM_BANDWIDTH_POSTCOPY value turns out
>to be suboptimal a new VIR_DOMAIN_MIGRATE_MAX_SPEED_POSTCOPY flag for
>virDomainMigrateSetMaxSpeed and virDomainMigrateGetMaxSpeed may be used
>to set/get the maximum post-copy migration bandwidth while migration is
>already running.
>
>Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
>---
> include/libvirt/libvirt-domain.h | 15 +++++++++++++++
> src/libvirt-domain.c             | 11 ++++++++---
> 2 files changed, 23 insertions(+), 3 deletions(-)
>
>diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
>index 0388911ded..d99f9b690b 100644
>--- a/include/libvirt/libvirt-domain.h
>+++ b/include/libvirt/libvirt-domain.h
>@@ -903,6 +903,15 @@ typedef enum {
>  */
> # define VIR_MIGRATE_PARAM_BANDWIDTH         "bandwidth"
>
>+/**
>+ * VIR_MIGRATE_PARAM_BANDWIDTH_POSTCOPY:
>+ *
>+ * virDomainMigrate* params field: the maximum bandwidth (in MiB/s) that will

I guess granularity < 1 MiB/s is not worth the trouble of creating an
inconsistent API, is it?

>+ * be used for post-copy phase of a migration as VIR_TYPED_PARAM_ULLONG. If set
>+ * to 0 or omitted, post-copy migration speed will not be limited.
>+ */
>+# define VIR_MIGRATE_PARAM_BANDWIDTH_POSTCOPY "bandwidth.postcopy"
>+
> /**
>  * VIR_MIGRATE_PARAM_GRAPHICS_URI:
>  *
>@@ -1062,6 +1071,12 @@ int virDomainMigrateSetCompressionCache(virDomainPtr domain,
>                                         unsigned long long cacheSize,
>                                         unsigned int flags);
>
>+/* Domain migration speed flags. */
>+typedef enum {
>+    /* Set or get maximum speed of postcopy migration. */

post-copy is the spelling used for human-readable strings

>+    VIR_DOMAIN_MIGRATE_MAX_SPEED_POSTCOPY = (1 << 0),
>+} virDomainMigrateMaxSpeedFlags;
>+
> int virDomainMigrateSetMaxSpeed(virDomainPtr domain,
>                                 unsigned long bandwidth,
>                                 unsigned int flags);
>diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
>index 58b4863c8f..7b87b3716a 100644
>--- a/src/libvirt-domain.c
>+++ b/src/libvirt-domain.c
>@@ -9036,11 +9036,13 @@ virDomainMigrateSetCompressionCache(virDomainPtr domain,
>  * virDomainMigrateSetMaxSpeed:
>  * @domain: a domain object
>  * @bandwidth: migration bandwidth limit in MiB/s
>- * @flags: extra flags; not used yet, so callers should always pass 0
>+ * @flags: bitwise-OR of virDomainMigrateMaxSpeedFlags
>  *
>  * The maximum bandwidth (in MiB/s) that will be used to do migration
>  * can be specified with the bandwidth parameter. Not all hypervisors
>- * will support a bandwidth cap
>+ * will support a bandwidth cap. When VIR_DOMAIN_MIGRATE_MAX_SPEED_POSTCOPY
>+ * is set in @flags, this API sets the maximum bandwidth for the postcopy

post-copy

>+ * phase of the migration.
>  *
>  * Returns 0 in case of success, -1 otherwise.
>  */
>@@ -9077,10 +9079,13 @@ virDomainMigrateSetMaxSpeed(virDomainPtr domain,
>  * virDomainMigrateGetMaxSpeed:
>  * @domain: a domain object
>  * @bandwidth: return value of current migration bandwidth limit in MiB/s
>- * @flags: extra flags; not used yet, so callers should always pass 0
>+ * @flags: bitwise-OR of virDomainMigrateMaxSpeedFlags
>  *
>  * Get the current maximum bandwidth (in MiB/s) that will be used if the
>  * domain is migrated.  Not all hypervisors will support a bandwidth limit.
>+ * When VIR_DOMAIN_MIGRATE_MAX_SPEED_POSTCOPY is set in @flags, this API
>+ * gets the current maximum bandwidth for the postcopy phase of the

post-copy

>+ * migration.
>  *

Reviewed-by: Ján Tomko <jtomko at redhat.com>

Jano
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