On Fri, May 26, 2023 at 5:21 AM Juan Quintela <quint...@redhat.com> wrote:
>
> 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:-)
Happens to me all the time :)
>
> 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.
>
