| Message ID | 1543803511-34793-7-git-send-email-wei.w.wang@intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | virtio-balloon: free page hint support | expand |
On Mon, Dec 03, 2018 at 10:18:30AM +0800, Wei Wang wrote: > This patch adds a function to enable a precopy notifier callback outside > the migration subsystem to disable the bulk stage flag. This is needed by > the free page optimization offered by virtio-balloon. > > Signed-off-by: Wei Wang <wei.w.wang@intel.com> > CC: Dr. David Alan Gilbert <dgilbert@redhat.com> > CC: Juan Quintela <quintela@redhat.com> > CC: Michael S. Tsirkin <mst@redhat.com> > CC: Peter Xu <peterx@redhat.com> > --- > include/migration/misc.h | 1 + > migration/ram.c | 9 +++++++++ > 2 files changed, 10 insertions(+) > > diff --git a/include/migration/misc.h b/include/migration/misc.h > index 15f8d00..47e7ff5 100644 > --- a/include/migration/misc.h > +++ b/include/migration/misc.h > @@ -37,6 +37,7 @@ void precopy_infrastructure_init(void); > void precopy_add_notifier(NotifierWithReturn *n); > void precopy_remove_notifier(NotifierWithReturn *n); > int precopy_notify(PrecopyNotifyReason reason, Error **errp); > +void precopy_disable_bulk_stage(void); > > void ram_mig_init(void); > void qemu_guest_free_page_hint(void *addr, size_t len); > diff --git a/migration/ram.c b/migration/ram.c > index b90a3f2..739dc97 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -354,6 +354,15 @@ int precopy_notify(PrecopyNotifyReason reason, Error **errp) > return notifier_with_return_list_notify(&precopy_notifier_list, &pnd); > } > > +void precopy_disable_bulk_stage(void) > +{ > + if (!ram_state) { > + return; > + } > + > + ram_state->ram_bulk_stage = false; > +} > + This one is a bit tricky. E.g., I think it'll at least affect XBZRLE and compression somehow. Since we will have the on-off switch for balloon free page hinting so the user can at least decide what features to use, with that I don't see much issue with it so far. But I'd also like to see how other people see this change. Regards,
On 12/03/2018 01:31 PM, Peter Xu wrote: > On Mon, Dec 03, 2018 at 10:18:30AM +0800, Wei Wang wrote: >> This patch adds a function to enable a precopy notifier callback outside >> the migration subsystem to disable the bulk stage flag. This is needed by >> the free page optimization offered by virtio-balloon. >> >> Signed-off-by: Wei Wang <wei.w.wang@intel.com> >> CC: Dr. David Alan Gilbert <dgilbert@redhat.com> >> CC: Juan Quintela <quintela@redhat.com> >> CC: Michael S. Tsirkin <mst@redhat.com> >> CC: Peter Xu <peterx@redhat.com> >> --- >> include/migration/misc.h | 1 + >> migration/ram.c | 9 +++++++++ >> 2 files changed, 10 insertions(+) >> >> diff --git a/include/migration/misc.h b/include/migration/misc.h >> index 15f8d00..47e7ff5 100644 >> --- a/include/migration/misc.h >> +++ b/include/migration/misc.h >> @@ -37,6 +37,7 @@ void precopy_infrastructure_init(void); >> void precopy_add_notifier(NotifierWithReturn *n); >> void precopy_remove_notifier(NotifierWithReturn *n); >> int precopy_notify(PrecopyNotifyReason reason, Error **errp); >> +void precopy_disable_bulk_stage(void); >> >> void ram_mig_init(void); >> void qemu_guest_free_page_hint(void *addr, size_t len); >> diff --git a/migration/ram.c b/migration/ram.c >> index b90a3f2..739dc97 100644 >> --- a/migration/ram.c >> +++ b/migration/ram.c >> @@ -354,6 +354,15 @@ int precopy_notify(PrecopyNotifyReason reason, Error **errp) >> return notifier_with_return_list_notify(&precopy_notifier_list, &pnd); >> } >> >> +void precopy_disable_bulk_stage(void) >> +{ >> + if (!ram_state) { >> + return; >> + } >> + >> + ram_state->ram_bulk_stage = false; >> +} >> + > This one is a bit tricky. E.g., I think it'll at least affect XBZRLE > and compression somehow. Since we will have the on-off switch for > balloon free page hinting so the user can at least decide what > features to use, with that I don't see much issue with it so far. But > I'd also like to see how other people see this change. > Yes. I think it would be better that this optimization could co-exist with the compression feature. How about adding a new flag "ram_state->free_page_optimization_enabled"? We will then need a change in migration_bitmap_find_dirty: - if (rs->ram_bulk_stage && start > 0) { + if (!rs->free_page_optimization_enabled && rs->ram_bulk_stage && start > 0) { next = start + 1; } else { next = find_next_bit(bitmap, size, start); } Best, Wei
On 12/03/2018 04:20 PM, Wei Wang wrote: > On 12/03/2018 01:31 PM, Peter Xu wrote: >> On Mon, Dec 03, 2018 at 10:18:30AM +0800, Wei Wang wrote: >>> This patch adds a function to enable a precopy notifier callback >>> outside >>> the migration subsystem to disable the bulk stage flag. This is >>> needed by >>> the free page optimization offered by virtio-balloon. >>> >>> Signed-off-by: Wei Wang <wei.w.wang@intel.com> >>> CC: Dr. David Alan Gilbert <dgilbert@redhat.com> >>> CC: Juan Quintela <quintela@redhat.com> >>> CC: Michael S. Tsirkin <mst@redhat.com> >>> CC: Peter Xu <peterx@redhat.com> >>> --- >>> include/migration/misc.h | 1 + >>> migration/ram.c | 9 +++++++++ >>> 2 files changed, 10 insertions(+) >>> >>> diff --git a/include/migration/misc.h b/include/migration/misc.h >>> index 15f8d00..47e7ff5 100644 >>> --- a/include/migration/misc.h >>> +++ b/include/migration/misc.h >>> @@ -37,6 +37,7 @@ void precopy_infrastructure_init(void); >>> void precopy_add_notifier(NotifierWithReturn *n); >>> void precopy_remove_notifier(NotifierWithReturn *n); >>> int precopy_notify(PrecopyNotifyReason reason, Error **errp); >>> +void precopy_disable_bulk_stage(void); >>> void ram_mig_init(void); >>> void qemu_guest_free_page_hint(void *addr, size_t len); >>> diff --git a/migration/ram.c b/migration/ram.c >>> index b90a3f2..739dc97 100644 >>> --- a/migration/ram.c >>> +++ b/migration/ram.c >>> @@ -354,6 +354,15 @@ int precopy_notify(PrecopyNotifyReason reason, >>> Error **errp) >>> return >>> notifier_with_return_list_notify(&precopy_notifier_list, &pnd); >>> } >>> +void precopy_disable_bulk_stage(void) >>> +{ >>> + if (!ram_state) { >>> + return; >>> + } >>> + >>> + ram_state->ram_bulk_stage = false; >>> +} >>> + >> This one is a bit tricky. E.g., I think it'll at least affect XBZRLE >> and compression somehow. Since we will have the on-off switch for >> balloon free page hinting so the user can at least decide what >> features to use, with that I don't see much issue with it so far. But >> I'd also like to see how other people see this change. >> > > Yes. I think it would be better that this optimization could co-exist > with the > compression feature. > > How about adding a new flag "ram_state->free_page_optimization_enabled"? > > We will then need a change in migration_bitmap_find_dirty: > - if (rs->ram_bulk_stage && start > 0) { > + if (!rs->free_page_optimization_enabled && rs->ram_bulk_stage && > start > 0) { > next = start + 1; > } else { > next = find_next_bit(bitmap, size, start); > } > Btw, with the new flag, this patch is not needed, so "ram_bulk_stage" will not be changed. Best, Wei
diff --git a/include/migration/misc.h b/include/migration/misc.h index 15f8d00..47e7ff5 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -37,6 +37,7 @@ void precopy_infrastructure_init(void); void precopy_add_notifier(NotifierWithReturn *n); void precopy_remove_notifier(NotifierWithReturn *n); int precopy_notify(PrecopyNotifyReason reason, Error **errp); +void precopy_disable_bulk_stage(void); void ram_mig_init(void); void qemu_guest_free_page_hint(void *addr, size_t len); diff --git a/migration/ram.c b/migration/ram.c index b90a3f2..739dc97 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -354,6 +354,15 @@ int precopy_notify(PrecopyNotifyReason reason, Error **errp) return notifier_with_return_list_notify(&precopy_notifier_list, &pnd); } +void precopy_disable_bulk_stage(void) +{ + if (!ram_state) { + return; + } + + ram_state->ram_bulk_stage = false; +} + uint64_t ram_bytes_remaining(void) { return ram_state ? (ram_state->migration_dirty_pages * TARGET_PAGE_SIZE) :
This patch adds a function to enable a precopy notifier callback outside the migration subsystem to disable the bulk stage flag. This is needed by the free page optimization offered by virtio-balloon. Signed-off-by: Wei Wang <wei.w.wang@intel.com> CC: Dr. David Alan Gilbert <dgilbert@redhat.com> CC: Juan Quintela <quintela@redhat.com> CC: Michael S. Tsirkin <mst@redhat.com> CC: Peter Xu <peterx@redhat.com> --- include/migration/misc.h | 1 + migration/ram.c | 9 +++++++++ 2 files changed, 10 insertions(+)