Leonardo Brás <leob...@redhat.com> wrote:
> On Mon, 2023-05-15 at 21:57 +0200, Juan Quintela wrote:
>> When we sent a page through QEMUFile hooks (RDMA) there are three
>> posiblities:
>> - We are not using RDMA. return RAM_SAVE_CONTROL_DELAYED and
>> control_save_page() returns false to let anything else to proceed.
>> - There is one error but we are using RDMA. Then we return a negative
>> value, control_save_page() needs to return true.
>> - Everything goes well and RDMA start the sent of the page
>> asynchronously. It returns RAM_SAVE_CONTROL_DELAYED and we need to
>> return 1 for ram_save_page_legacy.
>>
>> Clear?
>>
>> I know, I know, the interfaz is as bad as it gets. I think that now
>> it is a bit clearer, but this needs to be done some other way.
>
> interface?
Yeap. I used the Spanish spelling, that, you know, in English is wrong O:-)
Thanks.
>> diff --git a/migration/rdma.c b/migration/rdma.c
>> index 416dec00a2..12d3c23fdc 100644
>> --- a/migration/rdma.c
>> +++ b/migration/rdma.c
>> @@ -3239,13 +3239,12 @@ qio_channel_rdma_shutdown(QIOChannel *ioc,
>> *
>> * @size : Number of bytes to transfer
>> *
>> - * @bytes_sent : User-specificed pointer to indicate how many bytes were
>> + * @pages_sent : User-specificed pointer to indicate how many pages were
>> * sent. Usually, this will not be more than a few bytes of
>> * the protocol because most transfers are sent
>> asynchronously.
>> */
>
> There is new doc to pages_sent but the parameter is not added to the signature
> bellow. Am I missing something?
Good catch.
I redid this patch several times. And it appears that I forgot some leftovers.
>
>> -static size_t qemu_rdma_save_page(QEMUFile *f,
>> - ram_addr_t block_offset, ram_addr_t
>> offset,
>> - size_t size, uint64_t *bytes_sent)
>> +static int qemu_rdma_save_page(QEMUFile *f, ram_addr_t block_offset,
>> + ram_addr_t offset, size_t size)
>> {
>> QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(qemu_file_get_ioc(f));
>> RDMAContext *rdma;
>> @@ -3277,18 +3276,6 @@ static size_t qemu_rdma_save_page(QEMUFile *f,
>> goto err;
>> }
>>
>> - /*
>> - * We always return 1 bytes because the RDMA
>> - * protocol is completely asynchronous. We do not yet know
>> - * whether an identified chunk is zero or not because we're
>> - * waiting for other pages to potentially be merged with
>> - * the current chunk. So, we have to call qemu_update_position()
>> - * later on when the actual write occurs.
>> - */
>> - if (bytes_sent) {
>> - *bytes_sent = 1;
>> - }
>> -
>> /*
>> * Drain the Completion Queue if possible, but do not block,
>> * just poll.
>
> Oh, so this one complements 13/16.
> Since it doesn't do imaginary transfers anymore, there is no need to use
> bytes_sent pointer to keep track of them anymore.
>
> Other than the pages_sent above that I couldn't understand:
> Reviewed-by: Leonardo Bras <leob...@redhat.com>
Dropping that bit.
Thanks.
