Re: [PATCH v1 1/7] migration: Introduce structs for background sync

[Yong Huang]

On Thu, Sep 26, 2024 at 3:17 AM Peter Xu <peterx@redhat.com> wrote:

On Fri, Sep 20, 2024 at 10:43:31AM +0800, Yong Huang wrote:
> Yes, invoke migration_bitmap_sync_precopy more frequently is also my
> first idea but it involves bitmap updating and interfere with the behavior
> of page sending, it also affects the migration information stats and
> interfere other migration logic such as migration_update_rates().

Could you elaborate?

For example, what happens if we start to sync in ram_save_iterate() for
some time intervals (e.g. 5 seconds)?

I didn't try to sync in ram_save_iterate but in the migration_bitmap_sync_precopy.

If we use the migration_bitmap_sync_precopy in the ram_save_iterate function,

This approach seems to be correct. However, the bitmap will be updated as the

migration thread iterates through each dirty page in the RAMBlock list. Compared

to the existing implementation, this is different but still straightforward;

I'll give it a shot soon to see if it works.

Btw, we shouldn't have this extra sync exist if auto converge is disabled
no matter which way we use, because it's pure overhead when auto converge
is not in use.

Ok, I'll add the check in the next versioni.

 

Thanks,

--
Peter Xu

Thanks for the comment.

Yong

--

Best regards