* Peter Xu (peterx@redhat.com) wrote:
> After we updated the dirty bitmaps of ramblocks, we also need to update
> the critical fields in RAMState to make sure it is ready for a resume.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
> migration/ram.c | 40 +++++++++++++++++++++++++++++++++++++++-
> migration/trace-events | 1 +
> 2 files changed, 40 insertions(+), 1 deletion(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index a2a4b05d5c..d275875f54 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2250,6 +2250,36 @@ static int ram_init_all(RAMState **rsp)
> return 0;
> }
>
> +static void ram_state_resume_prepare(RAMState *rs, QEMUFile *out)
> +{
> + RAMBlock *block;
> + long pages = 0;
> +
> + /*
> + * Postcopy is not using xbzrle/compression, so no need for that.
> + * Also, since source are already halted, we don't need to care
> + * about dirty page logging as well.
> + */
> +
> + RAMBLOCK_FOREACH(block) {
> + pages += bitmap_count_one(block->bmap,
> + block->used_length >> TARGET_PAGE_BITS);
> + }
> +
> + /* This may not be aligned with current bitmaps. Recalculate. */
> + rs->migration_dirty_pages = pages;
migration_dirty_pages is uint64_t - so we should probably do the cast
above and keep 'pages' as uint64_t.
> + rs->last_seen_block = NULL;
> + rs->last_sent_block = NULL;
> + rs->last_page = 0;
> + rs->last_version = ram_list.version;
Do you need to explicitly set
rs->ram_bulk_stage = false;
if the failure happened just after the start of postcopy and no
requested pages had been sent, I think it might still be set?
> + /* Update RAMState cache of output QEMUFile */
> + rs->f = out;
> +
> + trace_ram_state_resume_prepare(pages);
> +}
> +
> /*
> * Each of ram_save_setup, ram_save_iterate and ram_save_complete has
> * long-running RCU critical section. When rcu-reclaims in the code
> @@ -3178,8 +3208,16 @@ out:
> static int ram_resume_prepare(MigrationState *s, void *opaque)
> {
> RAMState *rs = *(RAMState **)opaque;
> + int ret;
>
> - return ram_dirty_bitmap_sync_all(s, rs);
> + ret = ram_dirty_bitmap_sync_all(s, rs);
> + if (ret) {
> + return ret;
> + }
> +
> + ram_state_resume_prepare(rs, s->to_dst_file);
> +
> + return 0;
> }
>
> static SaveVMHandlers savevm_ram_handlers = {
> diff --git a/migration/trace-events b/migration/trace-events
> index 45b1d89217..f5913ff51c 100644
> --- a/migration/trace-events
> +++ b/migration/trace-events
> @@ -88,6 +88,7 @@ ram_dirty_bitmap_reload_complete(char *str) "%s"
> ram_dirty_bitmap_sync_start(void) ""
> ram_dirty_bitmap_sync_wait(void) ""
> ram_dirty_bitmap_sync_complete(void) ""
> +ram_state_resume_prepare(long v) "%ld"
>
> # migration/migration.c
> await_return_path_close_on_source_close(void) ""
Dave
> --
> 2.14.3
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK