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Re: [Qemu-devel] [RFC 10/29] migration: new property "x-postcopy-fast"
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [RFC 10/29] migration: new property "x-postcopy-fast" |
Date: |
Mon, 31 Jul 2017 19:52:24 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
* Peter Xu (address@hidden) wrote:
> This provides a way to start postcopy ASAP when migration starts. To do
> this, we need both:
>
> -global migration.x-postcopy-ram=on \
> -global migration.x-postcopy-fast=on
Can you explain why this is necessary? Both sides already know
they're doing a postcopy recovery don't they?
Dave
>
> Signed-off-by: Peter Xu <address@hidden>
> ---
> migration/migration.c | 9 ++++++++-
> migration/migration.h | 2 ++
> 2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 5b2602e..efee87e 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1936,6 +1936,11 @@ bool migrate_colo_enabled(void)
> return s->enabled_capabilities[MIGRATION_CAPABILITY_X_COLO];
> }
>
> +static bool postcopy_should_start(MigrationState *s)
> +{
> + return atomic_read(&s->start_postcopy) || s->start_postcopy_fast;
> +}
> +
> /*
> * Master migration thread on the source VM.
> * It drives the migration and pumps the data down the outgoing channel.
> @@ -2013,7 +2018,7 @@ static void *migration_thread(void *opaque)
> if (migrate_postcopy_ram() &&
> s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE &&
> pend_nonpost <= threshold_size &&
> - atomic_read(&s->start_postcopy)) {
> + postcopy_should_start(s)) {
>
> if (!postcopy_start(s, &old_vm_running)) {
> current_active_state =
> MIGRATION_STATUS_POSTCOPY_ACTIVE;
> @@ -2170,6 +2175,8 @@ static Property migration_properties[] = {
> send_configuration, true),
> DEFINE_PROP_BOOL("send-section-footer", MigrationState,
> send_section_footer, true),
> + DEFINE_PROP_BOOL("x-postcopy-fast", MigrationState,
> + start_postcopy_fast, false),
>
> /* Migration parameters */
> DEFINE_PROP_INT64("x-compress-level", MigrationState,
> diff --git a/migration/migration.h b/migration/migration.h
> index 70e3094..e902bae 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -113,6 +113,8 @@ struct MigrationState
>
> /* Flag set once the migration has been asked to enter postcopy */
> bool start_postcopy;
> + /* Set the flag if we want to start postcopy ASAP when migration starts
> */
> + bool start_postcopy_fast;
> /* Flag set after postcopy has sent the device state */
> bool postcopy_after_devices;
>
> --
> 2.7.4
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [RFC 06/29] migration: dump str in migrate_set_state trace, (continued)
- [Qemu-devel] [RFC 06/29] migration: dump str in migrate_set_state trace, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 08/29] migration: reuse mis->userfault_quit_fd, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 07/29] migration: better error handling with QEMUFile, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 09/29] migration: provide postcopy_fault_thread_notify(), Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 10/29] migration: new property "x-postcopy-fast", Peter Xu, 2017/07/28
- Re: [Qemu-devel] [RFC 10/29] migration: new property "x-postcopy-fast",
Dr. David Alan Gilbert <=
- [Qemu-devel] [RFC 11/29] migration: new postcopy-pause state, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 12/29] migration: allow dst vm pause on postcopy, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 13/29] migration: allow src return path to pause, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 14/29] migration: allow send_rq to fail, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 15/29] migration: allow fault thread to pause, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 16/29] qmp: hmp: add migrate "resume" option, Peter Xu, 2017/07/28