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Re: [Qemu-devel] [PATCH RFC v6 5/7] migration: fix the multifd code when
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [PATCH RFC v6 5/7] migration: fix the multifd code when receiving less channels |
Date: |
Tue, 30 Oct 2018 14:05:02 +0800 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Mon, Oct 29, 2018 at 08:58:16PM +0800, Fei Li wrote:
> In our current code, when multifd is used during migration, if there
> is an error before the destination receives all new channels, the
> source keeps running, however the destination does not exit but keeps
> waiting until the source is killed deliberately.
>
> Fix this by simply killing the destination when it fails to receive
> packet via some channel.
>
> Cc: Dr. David Alan Gilbert <address@hidden>
> Cc: Peter Xu <address@hidden>
> Signed-off-by: Fei Li <address@hidden>
> ---
> migration/channel.c | 7 ++++++-
> migration/migration.c | 9 +++++++--
> migration/migration.h | 2 +-
> migration/ram.c | 17 ++++++++++++++---
> migration/ram.h | 2 +-
> 5 files changed, 29 insertions(+), 8 deletions(-)
>
> diff --git a/migration/channel.c b/migration/channel.c
> index 33e0e9b82f..572be4245a 100644
> --- a/migration/channel.c
> +++ b/migration/channel.c
> @@ -44,7 +44,12 @@ void migration_channel_process_incoming(QIOChannel *ioc)
> error_report_err(local_err);
[1]
> }
> } else {
> - migration_ioc_process_incoming(ioc);
> + Error *local_err = NULL;
> + migration_ioc_process_incoming(ioc, &local_err);
> + if (local_err) {
> + error_report_err(local_err);
> + exit(EXIT_FAILURE);
I would still suggest that you don't quit. See TLS error at [1], it
only dumps the error. IMHO users can quit easily for dst vm, I'll
just let them decide if they want.
Then you can merge the error path for both.
> + }
> }
> }
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 8b36e7f184..87dfc7374f 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -541,7 +541,7 @@ void migration_fd_process_incoming(QEMUFile *f)
> migration_incoming_process();
> }
>
> -void migration_ioc_process_incoming(QIOChannel *ioc)
> +void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
> {
> MigrationIncomingState *mis = migration_incoming_get_current();
> bool start_migration;
> @@ -563,9 +563,14 @@ void migration_ioc_process_incoming(QIOChannel *ioc)
> */
> start_migration = !migrate_use_multifd();
> } else {
> + Error *local_err = NULL;
> /* Multiple connections */
> assert(migrate_use_multifd());
> - start_migration = multifd_recv_new_channel(ioc);
> + start_migration = multifd_recv_new_channel(ioc, &local_err);
> + if (local_err) {
> + error_propagate(errp, local_err);
> + return;
> + }
> }
>
> if (start_migration) {
> diff --git a/migration/migration.h b/migration/migration.h
> index f7813f8261..7df4d426d0 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -229,7 +229,7 @@ struct MigrationState
> void migrate_set_state(int *state, int old_state, int new_state);
>
> void migration_fd_process_incoming(QEMUFile *f);
> -void migration_ioc_process_incoming(QIOChannel *ioc);
> +void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp);
> void migration_incoming_process(void);
>
> bool migration_has_all_channels(void);
> diff --git a/migration/ram.c b/migration/ram.c
> index 4db3b3e8f4..8f03afe228 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1072,6 +1072,7 @@ out:
> static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque)
> {
> MultiFDSendParams *p = opaque;
> + MigrationState *s = migrate_get_current();
This seems to be the source part, then I'll suggest you split the
patch and keep this patch only touches the dest vm path.
> QIOChannel *sioc = QIO_CHANNEL(qio_task_get_source(task));
> Error *local_err = NULL;
>
> @@ -1080,6 +1081,7 @@ static void multifd_new_send_channel_async(QIOTask
> *task, gpointer opaque)
> }
>
> if (qio_task_propagate_error(task, &local_err)) {
> + migrate_set_state(&s->state, s->state, MIGRATION_STATUS_FAILED);
> if (multifd_save_cleanup(&local_err) != 0) {
> migrate_set_error(migrate_get_current(), local_err);
> }
> @@ -1337,16 +1339,20 @@ bool multifd_recv_all_channels_created(void)
> }
>
> /* Return true if multifd is ready for the migration, otherwise false */
> -bool multifd_recv_new_channel(QIOChannel *ioc)
> +bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
> {
> + MigrationIncomingState *mis = migration_incoming_get_current();
> MultiFDRecvParams *p;
> Error *local_err = NULL;
> int id;
>
> id = multifd_recv_initial_packet(ioc, &local_err);
> if (id < 0) {
> + error_propagate_prepend(errp, local_err,
> + "failed to receive packet via multifd channel %x: ",
> + multifd_recv_state->count);
> multifd_recv_terminate_threads(local_err, false);
> - return false;
> + goto fail;
> }
>
> p = &multifd_recv_state->params[id];
> @@ -1354,7 +1360,8 @@ bool multifd_recv_new_channel(QIOChannel *ioc)
> error_setg(&local_err, "multifd: received id '%d' already setup'",
> id);
> multifd_recv_terminate_threads(local_err, true);
> - return false;
> + error_propagate(errp, local_err);
> + goto fail;
> }
> p->c = ioc;
> object_ref(OBJECT(ioc));
> @@ -1366,6 +1373,10 @@ bool multifd_recv_new_channel(QIOChannel *ioc)
> QEMU_THREAD_JOINABLE);
> atomic_inc(&multifd_recv_state->count);
> return multifd_recv_state->count == migrate_multifd_channels();
> +fail:
> + qemu_fclose(mis->from_src_file);
> + mis->from_src_file = NULL;
> + return false;
Do we need this?
I'd suggest to put all cleanups into a single function. For dest vm
I say it's process_incoming_migration_bh.
Regards,
--
Peter Xu
[Qemu-devel] [PATCH RFC v6 4/7] migration: fix some segmentation faults when using multifd, Fei Li, 2018/10/29
[Qemu-devel] [PATCH RFC v6 6/7] migration: fix some error handling, Fei Li, 2018/10/29
[Qemu-devel] [PATCH RFC v6 7/7] qemu_thread_create: propagate the error to callers to handle, Fei Li, 2018/10/29