ovsdb: Fix copying weak references into transaction history.

Transaction history is used only to construct row data updates for
clients, it's not used for checking data integrity, hence it doesn't
need a copy of weak references.

Not copying this data saves a lot of CPU cycles and memory in some
cases.  For example, in 250-node density-heavy scenario in ovn-heater
these references can take up to 70% of RSS, which is about 8 GB of
essentially wasted memory as reported by valgrind massif:

 -------------------------------------------------------------------------------
   n        time(i)         total(B)    useful-heap(B) extra-heap(B)   stacks(B)
 -------------------------------------------------------------------------------
  20 1,011,495,832,314  11,610,557,104  10,217,785,620 1,392,771,484        0

 88.00% (10,217,785,620B) (heap allocation functions) malloc/new/new[]
 ->70.47% (8,181,819,064B) 0x455372: xcalloc__ (util.c:121)
   ->70.07% (8,135,785,424B) 0x41609D: ovsdb_weak_ref_clone (row.c:66)
     ->70.07% (8,135,785,424B) 0x41609D: ovsdb_row_clone (row.c:151)
       ->34.74% (4,034,041,440B) 0x41B7C9: ovsdb_txn_clone (transaction.c:1124)
       | ->34.74% (4,034,041,440B) 0x41B7C9: ovsdb_txn_add_to_history (transaction.c:1163)
       |   ->34.74% (4,034,041,440B) 0x41B7C9: ovsdb_txn_replay_commit (transaction.c:1198)
       |     ->34.74% (4,034,041,440B) 0x408C35: parse_txn (ovsdb-server.c:633)
       |       ->34.74% (4,034,041,440B) 0x408C35: read_db (ovsdb-server.c:663)
       |         ->34.74% (4,034,041,440B) 0x406C9D: main_loop (ovsdb-server.c:238)
       |           ->34.74% (4,034,041,440B) 0x406C9D: main (ovsdb-server.c:500)
       |
       ->34.74% (4,034,041,440B) 0x41B7DE: ovsdb_txn_clone (transaction.c:1125)
         ->34.74% (4,034,041,440B) 0x41B7DE: ovsdb_txn_add_to_history (transaction.c:1163)
           ->34.74% (4,034,041,440B) 0x41B7DE: ovsdb_txn_replay_commit (transaction.c:1198)
             ->34.74% (4,034,041,440B) 0x408C35: parse_txn (ovsdb-server.c:633)
               ->34.74% (4,034,041,440B) 0x408C35: read_db (ovsdb-server.c:663)
                 ->34.74% (4,034,041,440B) 0x406C9D: main_loop (ovsdb-server.c:238)
                   ->34.74% (4,034,041,440B) 0x406C9D: main (ovsdb-server.c:500)

Replacing ovsdb_row_clone() with ovsdb_row_datum_clone() to avoid
cloning unnecessary metadata.  The ovsdb_txn_clone() function re-named
to avoid issues if it will be re-used in the future for some other
use-case.

Acked-by: Dumitru Ceara <dceara@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

0 files changed, 0 insertions, 0 deletions