* 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.
> + 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?
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
