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Re: [Qemu-devel] [PATCH v2 3/5] migration: remove unnecessary variables
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v2 3/5] migration: remove unnecessary variables len in QIOChannelRDMA |
Date: |
Thu, 26 Apr 2018 17:40:11 +0100 |
User-agent: |
Mutt/1.9.5 (2018-04-13) |
* Lidong Chen (address@hidden) wrote:
> Because qio_channel_rdma_writev and qio_channel_rdma_readv maybe invoked
> by different threads concurrently, this patch removes unnecessary variables
> len in QIOChannelRDMA and use local variable instead.
>
> Signed-off-by: Lidong Chen <address@hidden>
I'm OK with this patch as is; but now you're making me worried that I
don't quite understand what thrads are accessing it at the same time; we
need to document/comment what's accessed concurrently.
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> ---
> migration/rdma.c | 15 +++++++--------
> 1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/migration/rdma.c b/migration/rdma.c
> index c745427..f5c1d02 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -404,7 +404,6 @@ struct QIOChannelRDMA {
> QIOChannel parent;
> RDMAContext *rdma;
> QEMUFile *file;
> - size_t len;
> bool blocking; /* XXX we don't actually honour this yet */
> };
>
> @@ -2640,6 +2639,7 @@ static ssize_t qio_channel_rdma_writev(QIOChannel *ioc,
> int ret;
> ssize_t done = 0;
> size_t i;
> + size_t len = 0;
>
> CHECK_ERROR_STATE();
>
> @@ -2659,10 +2659,10 @@ static ssize_t qio_channel_rdma_writev(QIOChannel
> *ioc,
> while (remaining) {
> RDMAControlHeader head;
>
> - rioc->len = MIN(remaining, RDMA_SEND_INCREMENT);
> - remaining -= rioc->len;
> + len = MIN(remaining, RDMA_SEND_INCREMENT);
> + remaining -= len;
>
> - head.len = rioc->len;
> + head.len = len;
> head.type = RDMA_CONTROL_QEMU_FILE;
>
> ret = qemu_rdma_exchange_send(rdma, &head, data, NULL, NULL,
> NULL);
> @@ -2672,8 +2672,8 @@ static ssize_t qio_channel_rdma_writev(QIOChannel *ioc,
> return ret;
> }
>
> - data += rioc->len;
> - done += rioc->len;
> + data += len;
> + done += len;
> }
> }
>
> @@ -2768,8 +2768,7 @@ static ssize_t qio_channel_rdma_readv(QIOChannel *ioc,
> }
> }
> }
> - rioc->len = done;
> - return rioc->len;
> + return done;
> }
>
> /*
> --
> 1.8.3.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH v2 0/5] Enable postcopy RDMA live migration, Lidong Chen, 2018/04/25
- [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
- [Qemu-devel] [PATCH v2 4/5] migration: implement bi-directional RDMA QIOChannel, Lidong Chen, 2018/04/25