* Wei Yang (richard.weiyang@xxxxxxxxxx) wrote:
> On Wed, Mar 23, 2016 at 06:48:22AM +0000, Li, Liang Z wrote:
> [...]
> >> > 8. Pseudo code
> >> > Dirty page logging should be enabled before getting the free page
> >> > information from guest, this is important because during the process
> >> > of getting free pages, some free pages may be used and written by the
> >> > guest, dirty page logging can trace these pages. The pseudo code is
> >> > like below:
> >> >
> >> > -----------------------------------------------
> >> > MigrationState *s = migrate_get_current();
> >> > ...
> >> >
> >> > memory_global_dirty_log_start();
> >> >
> >> > if (get_guest_mem_info(&info)) {
> >> > while (!get_free_page_bmap(free_page_bitmap, drop_page_cache)
> >> &&
> >> > s->state != MIGRATION_STATUS_CANCELLING) {
> >> > usleep(1000) // sleep for 1 ms
> >> > }
> >> >
> >> > tighten_free_page_bmap =
> >> tighten_guest_free_pages(free_page_bitmap);
> >> > filter_out_guest_free_pages(tighten_free_page_bmap);
> >> > }
> >>
> >> Given the typical speed of networks; it wouldn't do too much harm to start
> >> sending assuming all pages are dirty and then when the guest finally gets
> >> around to finishing the bitmap then update, so it's asynchronous - and then if
> >> the guest never responds we don't really care.
> >
> >Indeed, thanks!
> >
>
> This is interesting. By doing so, the threshold I mentioned in another mail is
> not necessary, since we can do it in parallel.
Actually I just realised it's a little more complex; we can't sync the dirty
bitmap again from the guest until after we've received the guests 'free' bitmap;
that's because we wouldn't know if a 'dirty' page reflected that a page declared
as 'free' had now been reused - so there is still an ordering there.
Dave
>
> >Liang
> >>
> >> Dave
> >>
> >> >
> >> > migration_bitmap_sync();
> >> > ...
> >> >
> >> > -----------------------------------------------
> >> >
> >> >
> >> > --
> >> > 1.9.1
> >> >
> >> --
> >> Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK
> >N�����r��y���b�X��ǧv�^�){.n�+����h����ܨ}���Ơz�&j:+v�������zZ+��+zf���h���~����i���z� �w���?����&�)ߢf
> --
> Richard Yang\nHelp you, Help me
--
Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK
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