On Wed, Mar 14, 2018 at 02:50:44PM +0800, Wei Wang wrote: > On 03/14/2018 10:51 AM, Michael S. Tsirkin wrote: > > On Wed, Mar 14, 2018 at 10:41:36AM +0800, Wei Wang wrote: > > > On 03/14/2018 12:35 AM, Michael S. Tsirkin wrote: > > > > On Wed, Mar 07, 2018 at 08:34:25PM +0800, Wei Wang wrote: > > > > > Start the free page optimization after the migration bitmap is > > > > > synchronized. This can't be used in the stop© phase since the > > > > > guest > > > > > is paused. Make sure the guest reporting has stopped before > > > > > synchronizing the migration dirty bitmap. Currently, the optimization > > > > > is > > > > > added to precopy only. > > > > > > > > > > Signed-off-by: Wei Wang <wei.w.w...@intel.com> > > > > > CC: Dr. David Alan Gilbert <dgilb...@redhat.com> > > > > > CC: Juan Quintela <quint...@redhat.com> > > > > > CC: Michael S. Tsirkin <m...@redhat.com> > > > > > --- > > > > > migration/ram.c | 19 ++++++++++++++++++- > > > > > 1 file changed, 18 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git a/migration/ram.c b/migration/ram.c > > > > > index e172798..7b4c9b1 100644 > > > > > --- a/migration/ram.c > > > > > +++ b/migration/ram.c > > > > > @@ -51,6 +51,8 @@ > > > > > #include "qemu/rcu_queue.h" > > > > > #include "migration/colo.h" > > > > > #include "migration/block.h" > > > > > +#include "sysemu/balloon.h" > > > > > +#include "sysemu/sysemu.h" > > > > > /***********************************************************/ > > > > > /* ram save/restore */ > > > > > @@ -208,6 +210,8 @@ struct RAMState { > > > > > uint32_t last_version; > > > > > /* We are in the first round */ > > > > > bool ram_bulk_stage; > > > > > + /* The free pages optimization feature is supported */ > > > > > + bool free_page_support; > > > > > /* How many times we have dirty too many pages */ > > > > > int dirty_rate_high_cnt; > > > > > /* these variables are used for bitmap sync */ > > > > > @@ -775,7 +779,7 @@ unsigned long > > > > > migration_bitmap_find_dirty(RAMState *rs, RAMBlock *rb, > > > > > unsigned long *bitmap = rb->bmap; > > > > > unsigned long next; > > > > > - if (rs->ram_bulk_stage && start > 0) { > > > > > + if (rs->ram_bulk_stage && start > 0 && !rs->free_page_support) { > > > > > next = start + 1; > > > > > } else { > > > > > next = find_next_bit(bitmap, size, start); > > > > > @@ -833,6 +837,10 @@ static void migration_bitmap_sync(RAMState *rs) > > > > > int64_t end_time; > > > > > uint64_t bytes_xfer_now; > > > > > + if (rs->free_page_support) { > > > > > + balloon_free_page_stop(); > > > > > + } > > > > > + > > > > > ram_counters.dirty_sync_count++; > > > > > if (!rs->time_last_bitmap_sync) { > > > > > @@ -899,6 +907,10 @@ static void migration_bitmap_sync(RAMState *rs) > > > > > if (migrate_use_events()) { > > > > > > > > > > qapi_event_send_migration_pass(ram_counters.dirty_sync_count, NULL); > > > > > } > > > > > + > > > > > + if (rs->free_page_support && runstate_is_running()) { > > > > > + balloon_free_page_start(); > > > > > + } > > > > > } > > > > I think some of these conditions should go into > > > > balloon_free_page_start/stop. > > > > > > > > Checking runstate is generally problematic unless you > > > > also handle run state change notifiers as it can > > > > be manipulated from QMP. > > > How about moving the check of runstate to > > > virtio_balloon_poll_free_page_hints: > > > > > > while (dev->free_page_report_status < FREE_PAGE_REPORT_S_STOP && > > > runstate_is_running()) { > > > ... > > > } > > Hard to tell on the outset. E.g. why is just stop affected? Pls add > > comments explaining what happens if VM is not running when start or stop > > is called. > > > > > > > In this case, I think we won't need a notifier - if the run state is > > > changed > > > by qmp, the optimization thread will just exist. > > But you need to wake it up and notify the guest presumably? > > > > > I think it's not necessary to wake it up, because when the VM is not > running, there will be no hints reported to the vq, and the optimization > thread exits. (there is no issue in that case) > Probably we can add a notifier which calls virtio_balloon_free_page_stop() > when qmp wakes up the VM. > > Best, > Wei
set_status callback is invoked so you can use that maybe. Might be a good idea to handle a bunch of other corner cases e.g. if guest driver is loaded when migration is already in progress. -- MST --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscr...@lists.oasis-open.org For additional commands, e-mail: virtio-dev-h...@lists.oasis-open.org