Re: [PATCH 4/7] migration: Do chunk page in postcopy_each_ram_send_discard()

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Peter Xu (peterx@redhat.com) wrote:
> Right now we loop ramblocks for twice, the 1st time chunk the dirty bits with
> huge page information; the 2nd time we send the discard ranges.  That's not
> necessary - we can do them in a single loop.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  migration/ram.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index e3876181ab..ecc744d54d 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2473,6 +2473,8 @@ static int postcopy_send_discard_bm_ram(MigrationState *ms, RAMBlock *block)
>      return 0;
>  }
>  
> +static void postcopy_chunk_hostpages_pass(MigrationState *ms, RAMBlock *block);
> +
>  /**
>   * postcopy_each_ram_send_discard: discard all RAMBlocks
>   *
> @@ -2494,6 +2496,14 @@ static int postcopy_each_ram_send_discard(MigrationState *ms)
>      RAMBLOCK_FOREACH_NOT_IGNORED(block) {
>          postcopy_discard_send_init(ms, block->idstr);
>  
> +        /*
> +         * Deal with TPS != HPS and huge pages.  It discard any partially sent
> +         * host-page size chunks, mark any partially dirty host-page size
> +         * chunks as all dirty.  In this case the host-page is the host-page
> +         * for the particular RAMBlock, i.e. it might be a huge page.
> +         */
> +        postcopy_chunk_hostpages_pass(ms, block);
> +
>          /*
>           * Postcopy sends chunks of bitmap over the wire, but it
>           * just needs indexes at this point, avoids it having
> @@ -2594,7 +2604,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, RAMBlock *block)
>  int ram_postcopy_send_discard_bitmap(MigrationState *ms)
>  {
>      RAMState *rs = ram_state;
> -    RAMBlock *block;
>  
>      RCU_READ_LOCK_GUARD();
>  
> @@ -2606,15 +2615,6 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms)
>      rs->last_sent_block = NULL;
>      rs->last_page = 0;
>  
> -    RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> -        /*
> -         * Deal with TPS != HPS and huge pages.  It discard any partially sent
> -         * host-page size chunks, mark any partially dirty host-page size
> -         * chunks as all dirty.  In this case the host-page is the host-page
> -         * for the particular RAMBlock, i.e. it might be a huge page.
> -         */
> -        postcopy_chunk_hostpages_pass(ms, block);
> -    }
>      trace_ram_postcopy_send_discard_bitmap();
>  
>      return postcopy_each_ram_send_discard(ms);
> -- 
> 2.32.0
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK