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Re: [Qemu-devel] [PATCH 2/3] migration: fix migrate_cancel leads live_mi
From: |
Juan Quintela |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] migration: fix migrate_cancel leads live_migration thread hung forever |
Date: |
Wed, 24 Jul 2019 10:47:31 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) |
Ivan Ren <address@hidden> wrote:
> When we 'migrate_cancel' a multifd migration, live_migration thread may
> hung forever at some points, because of multifd_send_thread has already
> exit for socket error:
> 1. multifd_send_pages may hung at qemu_sem_wait(&multifd_send_state->
> channels_ready)
> 2. multifd_send_sync_main my hung at qemu_sem_wait(&multifd_send_state->
> sem_sync)
>
> Signed-off-by: Ivan Ren <address@hidden>
> ---
> migration/ram.c | 23 +++++++++++++++++++----
> 1 file changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index f8908286c2..e4eb9c441f 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1097,7 +1097,11 @@ static void *multifd_send_thread(void *opaque)
> {
> MultiFDSendParams *p = opaque;
> Error *local_err = NULL;
> - int ret;
> + int ret = 0;
I agree with the ret change.
> +
> + uint32_t used = 0;
> + uint64_t packet_num = 0;
> + uint32_t flags = 0;
This movement is unneeded.
> trace_multifd_send_thread_start(p->id);
> rcu_register_thread();
> @@ -1113,9 +1117,9 @@ static void *multifd_send_thread(void *opaque)
> qemu_mutex_lock(&p->mutex);
>
> if (p->pending_job) {
> - uint32_t used = p->pages->used;
> - uint64_t packet_num = p->packet_num;
> - uint32_t flags = p->flags;
> + used = p->pages->used;
> + packet_num = p->packet_num;
> + flags = p->flags;
>
> p->next_packet_size = used * qemu_target_page_size();
> multifd_send_fill_packet(p);
> @@ -1164,6 +1168,17 @@ out:
> multifd_send_terminate_threads(local_err);
> }
>
> + /*
> + * Error happen, I will exit, but I can't just leave, tell
> + * who pay attention to me.
> + */
> + if (ret != 0) {
> + if (flags & MULTIFD_FLAG_SYNC) {
> + qemu_sem_post(&multifd_send_state->sem_sync);
> + }
> + qemu_sem_post(&multifd_send_state->channels_ready);
> + }
The real change is just this one. Good catch, thanks.
Reviewed-by: Juan Quintela <address@hidden>
Later, Juan.
- Re: [Qemu-devel] [PATCH 2/3] migration: fix migrate_cancel leads live_migration thread hung forever,
Juan Quintela <=