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?
>
> Signed-off-by: Juan Quintela <quint...@redhat.com>
> ---
> migration/qemu-file.h | 14 ++++++--------
> migration/qemu-file.c | 12 ++++++------
> migration/ram.c | 10 +++-------
> migration/rdma.c | 19 +++----------------
> 4 files changed, 18 insertions(+), 37 deletions(-)
>
> diff --git a/migration/qemu-file.h b/migration/qemu-file.h
> index 37f42315c7..ed77996201 100644
> --- a/migration/qemu-file.h
> +++ b/migration/qemu-file.h
> @@ -49,11 +49,10 @@ typedef int (QEMURamHookFunc)(QEMUFile *f, uint64_t
> flags, void *data);
> * This function allows override of where the RAM page
> * is saved (such as RDMA, for example.)
> */
> -typedef size_t (QEMURamSaveFunc)(QEMUFile *f,
> - ram_addr_t block_offset,
> - ram_addr_t offset,
> - size_t size,
> - uint64_t *bytes_sent);
> +typedef int (QEMURamSaveFunc)(QEMUFile *f,
> + ram_addr_t block_offset,
> + ram_addr_t offset,
> + size_t size);
>
> typedef struct QEMUFileHooks {
> QEMURamHookFunc *before_ram_iterate;
> @@ -146,9 +145,8 @@ void ram_control_load_hook(QEMUFile *f, uint64_t flags,
> void *data);
> #define RAM_SAVE_CONTROL_NOT_SUPP -1000
> #define RAM_SAVE_CONTROL_DELAYED -2000
>
> -size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
> - ram_addr_t offset, size_t size,
> - uint64_t *bytes_sent);
> +int ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
> + ram_addr_t offset, size_t size);
> QIOChannel *qemu_file_get_ioc(QEMUFile *file);
>
> #endif
> diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> index 72e130631d..32ef5e9651 100644
> --- a/migration/qemu-file.c
> +++ b/migration/qemu-file.c
> @@ -336,14 +336,14 @@ void ram_control_load_hook(QEMUFile *f, uint64_t flags,
> void *data)
> }
> }
>
> -size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
> - ram_addr_t offset, size_t size,
> - uint64_t *bytes_sent)
> +int ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
> + ram_addr_t offset, size_t size)
> {
> if (f->hooks && f->hooks->save_page) {
> - int ret = f->hooks->save_page(f, block_offset,
> - offset, size, bytes_sent);
> -
> + int ret = f->hooks->save_page(f, block_offset, offset, size);
> + /*
> + * RAM_SAVE_CONTROL_* are negative values
> + */
> if (ret != RAM_SAVE_CONTROL_DELAYED &&
> ret != RAM_SAVE_CONTROL_NOT_SUPP) {
> if (ret < 0) {
> diff --git a/migration/ram.c b/migration/ram.c
> index 2d3927a15f..f9fcbb3bb8 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1173,23 +1173,19 @@ static int save_zero_page(PageSearchStatus *pss,
> QEMUFile *f, RAMBlock *block,
> static bool control_save_page(PageSearchStatus *pss, RAMBlock *block,
> ram_addr_t offset, int *pages)
> {
> - uint64_t bytes_xmit = 0;
> int ret;
>
> - *pages = -1;
> ret = ram_control_save_page(pss->pss_channel, block->offset, offset,
> - TARGET_PAGE_SIZE, &bytes_xmit);
> + TARGET_PAGE_SIZE);
> if (ret == RAM_SAVE_CONTROL_NOT_SUPP) {
> return false;
> }
>
> - if (bytes_xmit) {
> - *pages = 1;
> - }
> -
> if (ret == RAM_SAVE_CONTROL_DELAYED) {
> + *pages = 1;
> return true;
> }
> + *pages = ret;
> return true;
> }
>
> 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?
> -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>
