diff options
| author | Wei Wang <wei.w.wang@intel.com> | 2018-12-11 16:24:52 +0800 |
|---|---|---|
| committer | Dr. David Alan Gilbert <dgilbert@redhat.com> | 2019-03-06 10:49:18 +0000 |
| commit | 6eeb63f740874150d7b5921541948c29b920a21d (patch) | |
| tree | c33cce71b9ab41956cbdc2cde176e7b0bd20f651 /include/migration | |
| parent | bd2270608fa0112108aafcba89b87282c68db741 (diff) | |
migration/ram.c: add the free page optimization enable flag
This patch adds the free page optimization enable flag, and a function
to set this flag. When the free page optimization is enabled, not all
the pages are needed to be sent in the bulk stage.
Why using a new flag, instead of directly disabling ram_bulk_stage when
the optimization is running?
Thanks for Peter Xu's reminder that disabling ram_bulk_stage will affect
the use of compression. Please see save_page_use_compression. When
xbzrle and compression are used, if free page optimizaion causes the
ram_bulk_stage to be disabled, save_page_use_compression will return
false, which disables the use of compression. That is, if free page
optimization avoids the sending of half of the guest pages, the other
half of pages loses the benefits of compression in the meantime. Using a
new flag to let migration_bitmap_find_dirty skip the free pages in the
bulk stage will avoid the above issue.
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
CC: Dr. David Alan Gilbert <dgilbert@redhat.com>
CC: Juan Quintela <quintela@redhat.com>
CC: Michael S. Tsirkin <mst@redhat.com>
CC: Peter Xu <peterx@redhat.com>
Message-Id: <1544516693-5395-7-git-send-email-wei.w.wang@intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Diffstat (limited to 'include/migration')
| -rw-r--r-- | include/migration/misc.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/migration/misc.h b/include/migration/misc.h index dc46d3354f..5cdbabd094 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -38,6 +38,7 @@ void precopy_infrastructure_init(void); void precopy_add_notifier(NotifierWithReturn *n); void precopy_remove_notifier(NotifierWithReturn *n); int precopy_notify(PrecopyNotifyReason reason, Error **errp); +void precopy_enable_free_page_optimization(void); void ram_mig_init(void); void qemu_guest_free_page_hint(void *addr, size_t len); |