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ovsdb-idl: Make it possible to omit or pay less attention to columns.

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ovs-vswitchd has no need to replicate some parts of the database.  In
particular, it doesn't need to replicate the bits that it never reads,
such as the external_ids column in the Open_vSwitch table.  This saves
some memory, CPU time, and bandwidth to the database.

Another type of column that benefits from special treatment is "write-only
columns", that is, those that ovs-vswitchd writes and keeps up-to-date but
never expects another client to write, such as the cur_cfg column in the
Open_vSwitch table.  If the IDL reports that the database has changed when
ovs-vswitchd updates such a column, then ovs-vswitchd reconfigures itself
for no reason, wasting CPU time.  This commit also adds support for such
columns.
This commit is contained in:
Ben Pfaff
2010-08-11 15:41:41 -07:00
parent f2f7be8696
commit c547535a7c
3 changed files with 127 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

117
lib/ovsdb-idl.c
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@@ -112,13 +112,13 @@ static void ovsdb_idl_send_monitor_request(struct ovsdb_idl *);
static void ovsdb_idl_parse_update(struct ovsdb_idl *, const struct json *);
static struct ovsdb_error *ovsdb_idl_parse_update__(struct ovsdb_idl *,
const struct json *);
static void ovsdb_idl_process_update(struct ovsdb_idl_table *,
static bool ovsdb_idl_process_update(struct ovsdb_idl_table *,
const struct uuid *,
const struct json *old,
const struct json *new);
static void ovsdb_idl_insert_row(struct ovsdb_idl_row *, const struct json *);
static void ovsdb_idl_delete_row(struct ovsdb_idl_row *);
static void ovsdb_idl_modify_row(struct ovsdb_idl_row *, const struct json *);
static bool ovsdb_idl_modify_row(struct ovsdb_idl_row *, const struct json *);
static bool ovsdb_idl_row_is_orphan(const struct ovsdb_idl_row *);
static struct ovsdb_idl_row *ovsdb_idl_row_create__(
@@ -159,6 +159,8 @@ ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class)
shash_add_assert(&idl->table_by_name, tc->name, table);
table->class = tc;
table->modes = xmalloc(tc->n_columns);
memset(table->modes, OVSDB_IDL_MODE_RW, tc->n_columns);
shash_init(&table->columns);
for (j = 0; j < tc->n_columns; j++) {
const struct ovsdb_idl_column *column = &tc->columns[j];
@@ -189,6 +191,7 @@ ovsdb_idl_destroy(struct ovsdb_idl *idl)
struct ovsdb_idl_table *table = &idl->tables[i];
shash_destroy(&table->columns);
hmap_destroy(&table->rows);
free(table->modes);
}
shash_destroy(&idl->table_by_name);
free(idl->tables);
@@ -290,6 +293,7 @@ ovsdb_idl_run(struct ovsdb_idl *idl)
} else if (msg->type == JSONRPC_REPLY
&& idl->monitor_request_id
&& json_equal(idl->monitor_request_id, msg->id)) {
idl->change_seqno++;
json_destroy(idl->monitor_request_id);
idl->monitor_request_id = NULL;
ovsdb_idl_clear(idl);
@@ -357,6 +361,65 @@ ovsdb_idl_force_reconnect(struct ovsdb_idl *idl)
{
jsonrpc_session_force_reconnect(idl->session);
}
static void
ovsdb_idl_set_mode(struct ovsdb_idl *idl,
const struct ovsdb_idl_column *column,
enum ovsdb_idl_mode mode)
{
size_t i;
for (i = 0; i < idl->class->n_tables; i++) {
const struct ovsdb_idl_table *table = &idl->tables[i];
const struct ovsdb_idl_table_class *tc = table->class;
if (column >= tc->columns && column < &tc->columns[tc->n_columns]) {
unsigned char *modep = &table->modes[column - tc->columns];
assert(*modep == OVSDB_IDL_MODE_RW || *modep == mode);
*modep = mode;
return;
}
}
NOT_REACHED();
}
/* By default, 'idl' replicates all of the columns in the remote database, and
* ovsdb_idl_run() returns true upon a change to any column in the database.
* Call this function to avoid alerting ovsdb_idl_run()'s caller upon changes
* to 'column'.
*
* This is useful for columns that a client treats as "write-only", that is, it
* updates them but doesn't want to get alerted about its own updates. It also
* won't be alerted about other clients' updates, so this is suitable only for
* use by a client that "owns" a particular column.
*
* The client must be careful not to retain pointers to data in 'column' across
* calls to ovsdb_idl_run(), even when that function returns false, because
* the client is not alerted to changes.
*
* This function should be called after ovsdb_idl_create(), but before the
* first call to ovsdb_idl_run(). For any given column, this function may be
* called or ovsdb_idl_omit() may be called, but not both. */
void
ovsdb_idl_set_write_only(struct ovsdb_idl *idl,
const struct ovsdb_idl_column *column)
{
ovsdb_idl_set_mode(idl, column, OVSDB_IDL_MODE_WO);
}
/* By default, 'idl' replicates all of the columns in the remote database.
* Call this function to omit replicating 'column'. This saves CPU time and
* bandwidth to the database.
*
* This function should be called after ovsdb_idl_create(), but before the
* first call to ovsdb_idl_run(). For any given column, this function may be
* called or ovsdb_idl_set_write_only() may be called, but not both. */
void
ovsdb_idl_omit(struct ovsdb_idl *idl, const struct ovsdb_idl_column *column)
{
ovsdb_idl_set_mode(idl, column, OVSDB_IDL_MODE_NONE);
}
static void
ovsdb_idl_send_monitor_request(struct ovsdb_idl *idl)
@@ -376,7 +439,9 @@ ovsdb_idl_send_monitor_request(struct ovsdb_idl *idl)
columns = json_array_create_empty();
for (i = 0; i < tc->n_columns; i++) {
const struct ovsdb_idl_column *column = &tc->columns[i];
json_array_add(columns, json_string_create(column->name));
if (table->modes[i] != OVSDB_IDL_MODE_NONE) {
json_array_add(columns, json_string_create(column->name));
}
}
json_object_put(monitor_request, "columns", columns);
json_object_put(monitor_requests, tc->name, monitor_request);
@@ -394,11 +459,7 @@ ovsdb_idl_send_monitor_request(struct ovsdb_idl *idl)
static void
ovsdb_idl_parse_update(struct ovsdb_idl *idl, const struct json *table_updates)
{
struct ovsdb_error *error;
idl->change_seqno++;
error = ovsdb_idl_parse_update__(idl, table_updates);
struct ovsdb_error *error = ovsdb_idl_parse_update__(idl, table_updates);
if (error) {
if (!VLOG_DROP_WARN(&syntax_rl)) {
char *s = ovsdb_error_to_string(error);
@@ -478,7 +539,9 @@ ovsdb_idl_parse_update__(struct ovsdb_idl *idl,
"and \"new\" members");
}
ovsdb_idl_process_update(table, &uuid, old_json, new_json);
if (ovsdb_idl_process_update(table, &uuid, old_json, new_json)) {
idl->change_seqno++;
}
}
}
@@ -499,7 +562,9 @@ ovsdb_idl_get_row(struct ovsdb_idl_table *table, const struct uuid *uuid)
return NULL;
}
static void
/* Returns true if a column with mode OVSDB_IDL_MODE_RW changed, false
* otherwise. */
static bool
ovsdb_idl_process_update(struct ovsdb_idl_table *table,
const struct uuid *uuid, const struct json *old,
const struct json *new)
@@ -516,6 +581,7 @@ ovsdb_idl_process_update(struct ovsdb_idl_table *table,
VLOG_WARN_RL(&semantic_rl, "cannot delete missing row "UUID_FMT" "
"from table %s",
UUID_ARGS(uuid), table->class->name);
return false;
}
} else if (!old) {
/* Insert row. */
@@ -526,14 +592,14 @@ ovsdb_idl_process_update(struct ovsdb_idl_table *table,
} else {
VLOG_WARN_RL(&semantic_rl, "cannot add existing row "UUID_FMT" to "
"table %s", UUID_ARGS(uuid), table->class->name);
ovsdb_idl_modify_row(row, new);
return ovsdb_idl_modify_row(row, new);
}
} else {
/* Modify row. */
if (row) {
/* XXX perhaps we should check the 'old' values? */
if (!ovsdb_idl_row_is_orphan(row)) {
ovsdb_idl_modify_row(row, new);
return ovsdb_idl_modify_row(row, new);
} else {
VLOG_WARN_RL(&semantic_rl, "cannot modify missing but "
"referenced row "UUID_FMT" in table %s",
@@ -546,13 +612,18 @@ ovsdb_idl_process_update(struct ovsdb_idl_table *table,
ovsdb_idl_insert_row(ovsdb_idl_row_create(table, uuid), new);
}
}
return true;
}
static void
/* Returns true if a column with mode OVSDB_IDL_MODE_RW changed, false
* otherwise. */
static bool
ovsdb_idl_row_update(struct ovsdb_idl_row *row, const struct json *row_json)
{
struct ovsdb_idl_table *table = row->table;
struct shash_node *node;
bool changed = false;
SHASH_FOR_EACH (node, json_object(row_json)) {
const char *column_name = node->name;
@@ -569,9 +640,12 @@ ovsdb_idl_row_update(struct ovsdb_idl_row *row, const struct json *row_json)
error = ovsdb_datum_from_json(&datum, &column->type, node->data, NULL);
if (!error) {
ovsdb_datum_swap(&row->old[column - table->class->columns],
&datum);
unsigned int column_idx = column - table->class->columns;
ovsdb_datum_swap(&row->old[column_idx], &datum);
ovsdb_datum_destroy(&datum, &column->type);
if (table->modes[column_idx] == OVSDB_IDL_MODE_RW) {
changed = true;
}
} else {
char *s = ovsdb_error_to_string(error);
VLOG_WARN_RL(&syntax_rl, "error parsing column %s in row "UUID_FMT
@@ -581,6 +655,7 @@ ovsdb_idl_row_update(struct ovsdb_idl_row *row, const struct json *row_json)
ovsdb_error_destroy(error);
}
}
return changed;
}
/* When a row A refers to row B through a column with a "refTable" constraint,
@@ -787,13 +862,19 @@ ovsdb_idl_delete_row(struct ovsdb_idl_row *row)
}
}
static void
/* Returns true if a column with mode OVSDB_IDL_MODE_RW changed, false
* otherwise. */
static bool
ovsdb_idl_modify_row(struct ovsdb_idl_row *row, const struct json *row_json)
{
bool changed;
ovsdb_idl_row_unparse(row);
ovsdb_idl_row_clear_arcs(row, true);
ovsdb_idl_row_update(row, row_json);
changed = ovsdb_idl_row_update(row, row_json);
ovsdb_idl_row_parse(row);
return changed;
}
static bool
@@ -1469,6 +1550,8 @@ ovsdb_idl_txn_write(const struct ovsdb_idl_row *row_,
assert(row->new != NULL);
assert(column_idx < class->n_columns);
assert(row->table->modes[column_idx] != OVSDB_IDL_MODE_NONE);
if (hmap_node_is_null(&row->txn_node)) {
hmap_insert(&row->table->idl->txn->txn_rows, &row->txn_node,
uuid_hash(&row->uuid));