Re: [PATCH v4 3/7] migration/multifd: Implement ram_save_target_page_multifd to handle multifd version of MigrationOps::ram_save_target_page.

[hao . xiang]

March 11, 2024 at 6:20 AM, "Peter Xu" <peterx@redhat.com> wrote:



> 
> On Sat, Mar 09, 2024 at 02:06:33AM +0000, hao.xiang@linux.dev wrote:
> 
> > 
> > > @@ -1122,10 +1122,6 @@ static int save_zero_page(RAMState *rs, 
> > > PageSearchStatus *pss,
> > 
> >  > QEMUFile *file = pss->pss_channel;
> > 
> >  > int len = 0;
> > 
> >  >
> > 
> >  > - if (migrate_zero_page_detection() == ZERO_PAGE_DETECTION_NONE) {
> > 
> >  > - return 0;
> > 
> >  > - }
> > 
> >  > 
> > 
> >  > We need to keep this to disable zero-page-detect on !multifd?
> > 
> >  
> > 
> >  So if multifd is enabled, the new parameter takes effect. If multifd is
> > 
> >  not enabled, zero page checking will always be done in the main thread,
> > 
> >  which is exactly the behavior it is now. I thought legacy migration is a
> > 
> >  deprecated feature so I am trying to not add new stuff to it.
> > 
> 
> There's no plan to deprecate legacy migrations, I think there was a plan to
> 
> make multifd the default, but I don't yet think it all thorougly yet, and
> 
> even if it happens it doesn't mean we'll remove legacy migration code.
> 
> When repost please still make sure this parameter works for both multifd
> 
> and !multifd.
> 
> Thanks,
> 
> -- 
> 
> Peter Xu


Sure. Fixed the issue now and reposted a new patchset.

>