On Tue, Feb 06, 2024 at 11:19:06PM +0000, Hao Xiang wrote:
> This implements the zero page detection and handling on the multifd
> threads.
>
> Signed-off-by: Hao Xiang <hao.xi...@bytedance.com>
> ---
> migration/multifd.c | 62 +++++++++++++++++++++++++++++++++++++++++----
> migration/multifd.h | 5 ++++
> 2 files changed, 62 insertions(+), 5 deletions(-)
>
> diff --git a/migration/multifd.c b/migration/multifd.c
> index a20d0ed10e..c031f947c7 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"
> @@ -278,6 +279,12 @@ 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);
> + }
> }
Please be noted taht p->normal_num will be dropped very soon, see:
https://lore.kernel.org/all/20240202102857.110210-6-pet...@redhat.com/
Please use p->pages->num instead.
This patch also relies on some changes in previous patch.. IMHO we can
split the patch better in this way:
- Patch 1: Add new parameter "zero-page-detection", support "none",
"legacy". You'll need to implement "none" here that we skip zero page
by returning 0 in save_zero_page() if "none".
- Patch 2: Add new "multifd" mode in above, implement it in the same
patch completely.
- Patch 3: introduce ram_save_target_page_multifd()
- Patch 4: test case
If you want to add "zeros" accounting, that can be done as more patches on
top.
Thanks,
--
Peter Xu
