Re: [PATCH 4/8] migration: Implement dirty-limit convergence algo

[Hyman]

在 2022/8/18 6:09, Peter Xu 写道:
> On Sat, Jul 23, 2022 at 03:49:16PM +0800, huangy81@chinatelecom.cn wrote:
> > From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> >
> > Implement dirty-limit convergence algo for live migration,
> > which is kind of like auto-converge algo but using dirty-limit
> > instead of cpu throttle to make migration convergent.
> >
> > Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> > ---
> >   migration/ram.c        | 53 +++++++++++++++++++++++++++++++++++++-------------
> >   migration/trace-events |  1 +
> >   2 files changed, 41 insertions(+), 13 deletions(-)
> >
> > diff --git a/migration/ram.c b/migration/ram.c
> > index b94669b..2a5cd23 100644
> > --- a/migration/ram.c
> > +++ b/migration/ram.c
> > @@ -45,6 +45,7 @@
> >   #include "qapi/error.h"
> >   #include "qapi/qapi-types-migration.h"
> >   #include "qapi/qapi-events-migration.h"
> > +#include "qapi/qapi-commands-migration.h"
> >   #include "qapi/qmp/qerror.h"
> >   #include "trace.h"
> >   #include "exec/ram_addr.h"
> > @@ -57,6 +58,8 @@
> >   #include "qemu/iov.h"
> >   #include "multifd.h"
> >   #include "sysemu/runstate.h"
> > +#include "sysemu/dirtylimit.h"
> > +#include "sysemu/kvm.h"
> >   
> >   #include "hw/boards.h" /* for machine_dump_guest_core() */
> >   
> > @@ -1139,6 +1142,21 @@ static void migration_update_rates(RAMState *rs, int64_t end_time)
> >       }
> >   }
> >   
> > +/*
> > + * Enable dirty-limit to throttle down the guest
> > + */
> > +static void migration_dirty_limit_guest(void)
> > +{
> > +    if (!dirtylimit_in_service()) {
> > +        MigrationState *s = migrate_get_current();
> > +        int64_t quota_dirtyrate = s->parameters.vcpu_dirty_limit;
> > +
> > +        /* Set quota dirtyrate if dirty limit not in service */
> > +        qmp_set_vcpu_dirty_limit(false, -1, quota_dirtyrate, NULL);
> > +        trace_migration_dirty_limit_guest(quota_dirtyrate);
> > +    }
> > +}
>
> What if migration is cancelled?  Do we have logic to stop the dirty limit,
> or should we?
Yes, we should have logic to stop dirty limit, i'll add that.
Thanks for your suggestion. :)

Yong
>