* Juan Quintela (quint...@redhat.com) wrote:
> This implements the zero page dection and handling.
>
> Signed-off-by: Juan Quintela <quint...@redhat.com>
> ---
> migration/multifd.c | 33 +++++++++++++++++++++++++++++++--
> 1 file changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/migration/multifd.c b/migration/multifd.c
> index 2e4dffd6c6..5c1fc70ce3 100644
> --- a/migration/multifd.c
> +++ b/migration/multifd.c
> @@ -11,6 +11,7 @@
> */
>
> #include "qemu/osdep.h"
> +#include "qemu/cutils.h"
> #include "qemu/rcu.h"
> #include "exec/target_page.h"
> #include "sysemu/sysemu.h"
> @@ -277,6 +278,12 @@ static void multifd_send_fill_packet(MultiFDSendParams
> *p)
>
> packet->offset[i] = cpu_to_be64(temp);
> }
> + for (i = 0; i < p->zero_num; i++) {
> + /* there are architectures where ram_addr_t is 32 bit */
> + uint64_t temp = p->zero[i];
> +
> + packet->offset[p->normal_num + i] = cpu_to_be64(temp);
OK, so if I'm understanding correctly here, the packet->offset array
starts with the 'normals' and then the zeros?
If so that probably needs a comment somewhere.
Other than that,
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> + }
> }
>
> static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
> @@ -362,6 +369,18 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams
> *p, Error **errp)
> p->normal[i] = offset;
> }
>
> + for (i = 0; i < p->zero_num; i++) {
> + uint64_t offset = be64_to_cpu(packet->offset[p->normal_num + i]);
> +
> + if (offset > (block->used_length - page_size)) {
> + error_setg(errp, "multifd: offset too long %" PRIu64
> + " (max " RAM_ADDR_FMT ")",
> + offset, block->used_length);
> + return -1;
> + }
> + p->zero[i] = offset;
> + }
> +
> return 0;
> }
>
> @@ -652,8 +671,14 @@ static void *multifd_send_thread(void *opaque)
> p->zero_num = 0;
>
> for (int i = 0; i < p->pages->num; i++) {
> - p->normal[p->normal_num] = p->pages->offset[i];
> - p->normal_num++;
> + if (buffer_is_zero(p->pages->block->host +
> p->pages->offset[i],
> + qemu_target_page_size())) {
> + p->zero[p->zero_num] = p->pages->offset[i];
> + p->zero_num++;
> + } else {
> + p->normal[p->normal_num] = p->pages->offset[i];
> + p->normal_num++;
> + }
> }
>
> if (p->normal_num) {
> @@ -1112,6 +1137,10 @@ static void *multifd_recv_thread(void *opaque)
> }
> }
>
> + for (int i = 0; i < p->zero_num; i++) {
> + memset(p->host + p->zero[i], 0, qemu_target_page_size());
> + }
> +
> if (flags & MULTIFD_FLAG_SYNC) {
> qemu_sem_post(&multifd_recv_state->sem_sync);
> qemu_sem_wait(&p->sem_sync);
> --
> 2.33.1
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
