* Peter Xu (pet...@redhat.com) wrote:
> This function calls three functions:
>
> - postcopy_discard_send_init(ms, block->idstr);
> - postcopy_chunk_hostpages_pass(ms, block);
> - postcopy_discard_send_finish(ms);
>
> However only the 2nd function call is meaningful. It's major role is to make
> sure dirty bits are applied in host-page-size granule, so there will be no
> partial dirty bits set for a whole host page if huge pages are used.
>
> The 1st/3rd call are for latter when we want to send the disgard ranges.
> They're mostly no-op here besides some tracepoints (which are misleading!).
>
> Drop them, then we can directly drop postcopy_chunk_hostpages() as a whole
> because we can call postcopy_chunk_hostpages_pass() directly.
>
> There're still some nice comments above postcopy_chunk_hostpages() that
> explain
> what it does. Copy it over to the caller's site.
>
> Signed-off-by: Peter Xu <pet...@redhat.com>
Yeh, I think originally the idea was to send some of the messages during
the chunking
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> migration/ram.c | 33 +++++++--------------------------
> 1 file changed, 7 insertions(+), 26 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index fb8c1a887e..e3876181ab 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2576,30 +2576,6 @@ static void
> postcopy_chunk_hostpages_pass(MigrationState *ms, RAMBlock *block)
> }
> }
>
> -/**
> - * postcopy_chunk_hostpages: discard any partially sent host page
> - *
> - * Utility for the outgoing postcopy code.
> - *
> - * 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
> - *
> - * @ms: current migration state
> - * @block: block we want to work with
> - */
> -static void postcopy_chunk_hostpages(MigrationState *ms, RAMBlock *block)
> -{
> - postcopy_discard_send_init(ms, block->idstr);
> -
> - /*
> - * Ensure that all partially dirty host pages are made fully dirty.
> - */
> - postcopy_chunk_hostpages_pass(ms, block);
> -
> - postcopy_discard_send_finish(ms);
> -}
> -
> /**
> * ram_postcopy_send_discard_bitmap: transmit the discard bitmap
> *
> @@ -2631,8 +2607,13 @@ int ram_postcopy_send_discard_bitmap(MigrationState
> *ms)
> rs->last_page = 0;
>
> RAMBLOCK_FOREACH_NOT_IGNORED(block) {
> - /* Deal with TPS != HPS and huge pages */
> - postcopy_chunk_hostpages(ms, 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();
>
> --
> 2.32.0
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
