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Re: [Qemu-devel] [RFC 24/29] migration: new message MIG_RP_MSG_RESUME_AC
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [RFC 24/29] migration: new message MIG_RP_MSG_RESUME_ACK |
Date: |
Thu, 3 Aug 2017 12:21:41 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
* Peter Xu (address@hidden) wrote:
> Creating new message to reply for MIG_CMD_POSTCOPY_RESUME. One uint32_t
> is used as payload to let the source know whether destination is ready
> to continue the migration.
>
> Signed-off-by: Peter Xu <address@hidden>
> ---
> migration/migration.c | 37 +++++++++++++++++++++++++++++++++++++
> migration/migration.h | 1 +
> migration/savevm.c | 3 ++-
> migration/trace-events | 1 +
> 4 files changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index c2b85ac..62f91ce 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -93,6 +93,7 @@ enum mig_rp_message_type {
> MIG_RP_MSG_REQ_PAGES_ID, /* data (start: be64, len: be32, id: string) */
> MIG_RP_MSG_REQ_PAGES, /* data (start: be64, len: be32) */
> MIG_RP_MSG_RECV_BITMAP, /* send recved_bitmap back to source */
> + MIG_RP_MSG_RESUME_ACK, /* tell source that we are ready to resume */
>
> MIG_RP_MSG_MAX
> };
> @@ -484,6 +485,14 @@ void migrate_send_rp_recv_bitmap(MigrationIncomingState
> *mis,
> trace_migrate_send_rp_recv_bitmap(block_name, res);
> }
>
> +void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value)
> +{
> + uint32_t buf;
> +
> + buf = cpu_to_be32(value);
> + migrate_send_rp_message(mis, MIG_RP_MSG_RESUME_ACK, sizeof(buf), &buf);
> +}
> +
> MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
> {
> MigrationCapabilityStatusList *head = NULL;
> @@ -1595,6 +1604,7 @@ static struct rp_cmd_args {
> [MIG_RP_MSG_REQ_PAGES] = { .len = 12, .name = "REQ_PAGES" },
> [MIG_RP_MSG_REQ_PAGES_ID] = { .len = -1, .name = "REQ_PAGES_ID" },
> [MIG_RP_MSG_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" },
> + [MIG_RP_MSG_RESUME_ACK] = { .len = 4, .name = "RESUME_ACK" },
> [MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" },
> };
>
> @@ -1652,6 +1662,25 @@ static int
> migrate_handle_rp_recv_bitmap(MigrationState *s, char *block_name)
> return ram_dirty_bitmap_reload(s, block);
> }
>
> +static int migrate_handle_rp_resume_ack(MigrationState *s, uint32_t value)
> +{
> + trace_source_return_path_thread_resume_ack(value);
> +
> + /*
> + * Currently value will always be one. It can be used in the
> + * future to notify source that destination cannot continue.
> + */
> + assert(value == 1);
Again I prefer the routine to fail than to assert.
Maybe it's worth having a constant rather than the magic 1.
> + /* Now both sides are active. */
> + migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_RECOVER,
> + MIGRATION_STATUS_POSTCOPY_ACTIVE);
> +
> + /* TODO: notify send thread that time to continue send pages */
> +
> + return 0;
> +}
> +
> /*
> * Handles messages sent on the return path towards the source VM
> *
> @@ -1771,6 +1800,14 @@ retry:
> }
> break;
>
> + case MIG_RP_MSG_RESUME_ACK:
> + tmp32 = ldl_be_p(buf);
> + if (migrate_handle_rp_resume_ack(ms, tmp32)) {
> + mark_source_rp_bad(ms);
> + goto out;
> + }
> + break;
> +
> default:
> break;
> }
> diff --git a/migration/migration.h b/migration/migration.h
> index 4d38308..2a3f905 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -206,5 +206,6 @@ int migrate_send_rp_req_pages(MigrationIncomingState
> *mis, const char* rbname,
> ram_addr_t start, size_t len);
> void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis,
> char *block_name);
> +void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value);
>
> #endif
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 2e330bc..02a67ac 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -1690,7 +1690,8 @@ static int
> loadvm_postcopy_handle_resume(MigrationIncomingState *mis)
> MIGRATION_STATUS_POSTCOPY_ACTIVE);
> qemu_sem_post(&mis->postcopy_pause_sem_fault);
>
> - /* TODO: Tell source that "we are ready" */
> + /* Tell source that "we are ready" */
> + migrate_send_rp_resume_ack(mis, 1);
>
> return 0;
> }
> diff --git a/migration/trace-events b/migration/trace-events
> index 04dd9d8..0b43fec 100644
> --- a/migration/trace-events
> +++ b/migration/trace-events
> @@ -116,6 +116,7 @@ source_return_path_thread_entry(void) ""
> source_return_path_thread_loop_top(void) ""
> source_return_path_thread_pong(uint32_t val) "%x"
> source_return_path_thread_shut(uint32_t val) "%x"
> +source_return_path_thread_resume_ack(uint32_t v) "%"PRIu32
> migrate_global_state_post_load(const char *state) "loaded state: %s"
> migrate_global_state_pre_save(const char *state) "saved state: %s"
> migration_thread_low_pending(uint64_t pending) "%" PRIu64
> --
> 2.7.4
Dave
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [RFC 24/29] migration: new message MIG_RP_MSG_RESUME_ACK,
Dr. David Alan Gilbert <=