On Sat, Jul 28, 2018 at 2:51 AM, Dr. David Alan Gilbert <dgilb...@redhat.com
> wrote:
> * Zhang Chen (zhangc...@gmail.com) wrote:
> > We record the address of the dirty pages that received,
> > it will help flushing pages that cached into SVM.
> >
> > Here, it is a trick, we record dirty pages by re-using migration
> > dirty bitmap. In the later patch, we will start the dirty log
> > for SVM, just like migration, in this way, we can record both
> > the dirty pages caused by PVM and SVM, we only flush those dirty
> > pages from RAM cache while do checkpoint.
> >
> > Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com>
> > Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> > ---
> > migration/ram.c | 33 +++++++++++++++++++++++++++++++++
> > 1 file changed, 33 insertions(+)
> >
> > diff --git a/migration/ram.c b/migration/ram.c
> > index 33ebd09d70..d1060f1337 100644
> > --- a/migration/ram.c
> > +++ b/migration/ram.c
> > @@ -3325,6 +3325,15 @@ static inline void
> > *colo_cache_from_block_offset(RAMBlock
> *block,
> > __func__, block->idstr);
> > return NULL;
> > }
> > +
> > + /*
> > + * During colo checkpoint, we need bitmap of these migrated pages.
> > + * It help us to decide which pages in ram cache should be flushed
> > + * into VM's RAM later.
> > + */
> > + if (!test_and_set_bit(offset >> TARGET_PAGE_BITS, block->bmap)) {
> > + ram_state->migration_dirty_pages++;
> > + }
> > return block->colo_cache + offset;
> > }
> >
> > @@ -3555,6 +3564,24 @@ int colo_init_ram_cache(void)
> > memcpy(block->colo_cache, block->host, block->used_length);
> > }
> > rcu_read_unlock();
> > + /*
> > + * Record the dirty pages that sent by PVM, we use this dirty bitmap
> together
> > + * with to decide which page in cache should be flushed into SVM's
> RAM. Here
> > + * we use the same name 'ram_bitmap' as for migration.
> > + */
> > + if (ram_bytes_total()) {
> > + RAMBlock *block;
> > +
> > + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
>
> I think those need updating to check for 'qemu_ram_is_migratable' - it
> might be worth moving RAMBLOCK_FOREACH_MIGRATABLE.
>
OK, I will change to the " RAMBLOCK_FOREACH_MIGRATABLE " in next version.
>
> > + unsigned long pages = block->max_length >> TARGET_PAGE_BITS;
> > +
> > + block->bmap = bitmap_new(pages);
> > + bitmap_set(block->bmap, 0, pages);
>
> Would it make sense to use the 'receivedmap' that was recently added
> for other uses rather than needing your own?
>
Maybe we can do this job as optimization in the future, currently we want
to make this series merged into upstream first.
Thanks
Zhang Chen
>
> Dave
>
> > + }
> > + }
> > + ram_state = g_new0(RAMState, 1);
> > + ram_state->migration_dirty_pages = 0;
> > +
> > return 0;
> >
> > out_locked:
> > @@ -3574,6 +3601,10 @@ void colo_release_ram_cache(void)
> > {
> > RAMBlock *block;
> >
> > + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
> > + g_free(block->bmap);
> > + block->bmap = NULL;
> > + }
> > rcu_read_lock();
> > QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
> > if (block->colo_cache) {
> > @@ -3582,6 +3613,8 @@ void colo_release_ram_cache(void)
> > }
> > }
> > rcu_read_unlock();
> > + g_free(ram_state);
> > + ram_state = NULL;
> > }
> >
> > /**
> > --
> > 2.17.1
> >
> --
> Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
>
