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Re: [Qemu-devel] [RFC 25/29] migration: introduce SaveVMHandlers.resume_
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [RFC 25/29] migration: introduce SaveVMHandlers.resume_prepare |
Date: |
Thu, 3 Aug 2017 12:38:01 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
* Peter Xu (address@hidden) wrote:
> This is hook function to be called when a postcopy migration wants to
> resume from a failure. For each module, it should provide its own
> recovery logic before we switch to the postcopy-active state.
Would a change-state handler be able to do this, or perhaps
the notifier chain I have in my shared memory world:
https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg06459.html
Dave
> Signed-off-by: Peter Xu <address@hidden>
> ---
> include/migration/register.h | 2 ++
> migration/migration.c | 20 +++++++++++++++++++-
> migration/savevm.c | 25 +++++++++++++++++++++++++
> migration/savevm.h | 1 +
> migration/trace-events | 1 +
> 5 files changed, 48 insertions(+), 1 deletion(-)
>
> diff --git a/include/migration/register.h b/include/migration/register.h
> index a0f1edd..b669362 100644
> --- a/include/migration/register.h
> +++ b/include/migration/register.h
> @@ -41,6 +41,8 @@ typedef struct SaveVMHandlers {
> LoadStateHandler *load_state;
> int (*load_setup)(QEMUFile *f, void *opaque);
> int (*load_cleanup)(void *opaque);
> + /* Called when postcopy migration wants to resume from failure */
> + int (*resume_prepare)(MigrationState *s, void *opaque);
> } SaveVMHandlers;
>
> int register_savevm_live(DeviceState *dev,
> diff --git a/migration/migration.c b/migration/migration.c
> index 62f91ce..6cb0ad3 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2150,7 +2150,25 @@ static bool postcopy_should_start(MigrationState *s)
> /* Return zero if success, or <0 for error */
> static int postcopy_do_resume(MigrationState *s)
> {
> - /* TODO: do the resume logic */
> + int ret;
> +
> + /*
> + * Call all the resume_prepare() hooks, so that modules can be
> + * ready for the migration resume.
> + */
> + ret = qemu_savevm_state_resume_prepare(s);
> + if (ret) {
> + error_report("%s: resume_prepare() failure detected: %d",
> + __func__, ret);
> + return ret;
> + }
> +
> + /*
> + * TODO: handshake with dest using MIG_CMD_RESUME,
> + * MIG_RP_MSG_RESUME_ACK, then switch source state to
> + * "postcopy-active"
> + */
> +
> return 0;
> }
>
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 02a67ac..08a4712 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -1004,6 +1004,31 @@ void qemu_savevm_state_setup(QEMUFile *f)
> }
> }
>
> +int qemu_savevm_state_resume_prepare(MigrationState *s)
> +{
> + SaveStateEntry *se;
> + int ret;
> +
> + trace_savevm_state_resume_prepare();
> +
> + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> + if (!se->ops || !se->ops->resume_prepare) {
> + continue;
> + }
> + if (se->ops && se->ops->is_active) {
> + if (!se->ops->is_active(se->opaque)) {
> + continue;
> + }
> + }
> + ret = se->ops->resume_prepare(s, se->opaque);
> + if (ret < 0) {
> + return ret;
> + }
> + }
> +
> + return 0;
> +}
> +
> /*
> * this function has three return values:
> * negative: there was one error, and we have -errno.
> diff --git a/migration/savevm.h b/migration/savevm.h
> index a5f3879..3193f04 100644
> --- a/migration/savevm.h
> +++ b/migration/savevm.h
> @@ -31,6 +31,7 @@
>
> bool qemu_savevm_state_blocked(Error **errp);
> void qemu_savevm_state_setup(QEMUFile *f);
> +int qemu_savevm_state_resume_prepare(MigrationState *s);
> void qemu_savevm_state_header(QEMUFile *f);
> int qemu_savevm_state_iterate(QEMUFile *f, bool postcopy);
> void qemu_savevm_state_cleanup(void);
> diff --git a/migration/trace-events b/migration/trace-events
> index 0b43fec..0fb2d1e 100644
> --- a/migration/trace-events
> +++ b/migration/trace-events
> @@ -37,6 +37,7 @@ savevm_send_postcopy_run(void) ""
> savevm_send_postcopy_resume(void) ""
> savevm_send_recv_bitmap(char *name) "%s"
> savevm_state_setup(void) ""
> +savevm_state_resume_prepare(void) ""
> savevm_state_header(void) ""
> savevm_state_iterate(void) ""
> savevm_state_cleanup(void) ""
> --
> 2.7.4
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [RFC 25/29] migration: introduce SaveVMHandlers.resume_prepare,
Dr. David Alan Gilbert <=