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migration: Drop postcopy_chunk_hostpages()

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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 <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Peter Xu 2021-12-07 19:50:12 +08:00 committed by Juan Quintela
parent dc57d6f2ec
commit e3fbf76021
1 changed files with 7 additions and 26 deletions
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33
migration/ram.c
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@ -2557,30 +2557,6 @@ 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
*
@ -2612,8 +2588,13 @@ 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();