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Re: [Qemu-devel] [PATCH v2 5/5] migration: Stop rdma yielding during inc
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v2 5/5] migration: Stop rdma yielding during incoming postcopy |
Date: |
Thu, 26 Apr 2018 18:54:55 +0100 |
User-agent: |
Mutt/1.9.5 (2018-04-13) |
* Lidong Chen (address@hidden) wrote:
> During incoming postcopy, the destination qemu will invoke
> qemu_rdma_wait_comp_channel in a seprate thread. So does not use rdma
> yield, and poll the completion channel fd instead.
>
> Signed-off-by: Lidong Chen <address@hidden>
OK, I think so; it's a bit delicate, but I can't currently see a better
way.
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> ---
> migration/rdma.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 0652224..4ba9fe2 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -1490,11 +1490,13 @@ static int qemu_rdma_wait_comp_channel(RDMAContext
> *rdma)
> * Coroutine doesn't start until migration_fd_process_incoming()
> * so don't yield unless we know we're running inside of a coroutine.
> */
> - if (rdma->migration_started_on_destination) {
> + if (rdma->migration_started_on_destination &&
> + migration_incoming_get_current()->state == MIGRATION_STATUS_ACTIVE) {
> yield_until_fd_readable(rdma->comp_channel->fd);
> } else {
> /* This is the source side, we're in a separate thread
> * or destination prior to migration_fd_process_incoming()
> + * after postcopy, the destination also in a seprate thread.
> * we can't yield; so we have to poll the fd.
> * But we need to be able to handle 'cancel' or an error
> * without hanging forever.
> --
> 1.8.3.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH v2 1/5] migration: disable RDMA WRITE after postcopy started, (continued)
- [Qemu-devel] [PATCH v2 1/5] migration: disable RDMA WRITE after postcopy started, Lidong Chen, 2018/04/25
- [Qemu-devel] [PATCH v2 2/5] migration: create a dedicated connection for rdma return path, Lidong Chen, 2018/04/25
- [Qemu-devel] [PATCH v2 3/5] migration: remove unnecessary variables len in QIOChannelRDMA, Lidong Chen, 2018/04/25
- [Qemu-devel] [PATCH v2 5/5] migration: Stop rdma yielding during incoming postcopy, Lidong Chen, 2018/04/25
- Re: [Qemu-devel] [PATCH v2 5/5] migration: Stop rdma yielding during incoming postcopy,
Dr. David Alan Gilbert <=
- [Qemu-devel] [PATCH v2 4/5] migration: implement bi-directional RDMA QIOChannel, Lidong Chen, 2018/04/25