From: Ben Pfaff Date: Wed, 11 Aug 2010 22:41:41 +0000 (-0700) Subject: ovsdb-idl: Make it possible to omit or pay less attention to columns. X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c547535a7c25ce4717b965b77877062796f12a95;p=openvswitch ovsdb-idl: Make it possible to omit or pay less attention to columns. 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. --- diff --git a/lib/ovsdb-idl-provider.h b/lib/ovsdb-idl-provider.h index c86396c9..040a6999 100644 --- a/lib/ovsdb-idl-provider.h +++ b/lib/ovsdb-idl-provider.h @@ -52,8 +52,31 @@ struct ovsdb_idl_table_class { size_t allocation_size; }; +enum ovsdb_idl_mode { + /* Client reads and may write this column and wants to be alerted upon + * updates to it. + * + * This is the default. */ + OVSDB_IDL_MODE_RW, + + /* Client may read and write this column, but doesn't care to be alerted + * when it is updated. + * + * 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. */ + OVSDB_IDL_MODE_WO, + + /* Client won't read or write this column at all. The IDL code can't + * prevent reading the column, but writing will cause assertion + * failures. */ + OVSDB_IDL_MODE_NONE +}; + struct ovsdb_idl_table { const struct ovsdb_idl_table_class *class; + unsigned char *modes; /* One of OVSDB_MODE_*, indexed by column. */ struct shash columns; /* Contains "const struct ovsdb_idl_column *"s. */ struct hmap rows; /* Contains "struct ovsdb_idl_row"s. */ struct ovsdb_idl *idl; /* Containing idl. */ diff --git a/lib/ovsdb-idl.c b/lib/ovsdb-idl.c index 2a437812..57d7b2ac 100644 --- a/lib/ovsdb-idl.c +++ b/lib/ovsdb-idl.c @@ -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)); diff --git a/lib/ovsdb-idl.h b/lib/ovsdb-idl.h index c09ba9b0..9179e380 100644 --- a/lib/ovsdb-idl.h +++ b/lib/ovsdb-idl.h @@ -53,6 +53,10 @@ unsigned int ovsdb_idl_get_seqno(const struct ovsdb_idl *); bool ovsdb_idl_has_ever_connected(const struct ovsdb_idl *); void ovsdb_idl_force_reconnect(struct ovsdb_idl *); +void ovsdb_idl_set_write_only(struct ovsdb_idl *, + const struct ovsdb_idl_column *); +void ovsdb_idl_omit(struct ovsdb_idl *, const struct ovsdb_idl_column *); + const struct ovsdb_idl_row *ovsdb_idl_get_row_for_uuid( const struct ovsdb_idl *, const struct ovsdb_idl_table_class *, const struct uuid *);