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MEDIUM: connections: Don't use a lock when moving connections to remove.

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Make it so we don't have to take a lock while moving a connection from
the idle list to the toremove_list by taking advantage of the MT_LIST.
This commit is contained in:
Olivier Houchard 2020-06-29 20:15:59 +02:00 committed by Willy Tarreau
parent f8f4c2ef60
commit ff1d0929b8
2 changed files with 29 additions and 26 deletions
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2
include/haproxy/connection.h
View File

@ -494,9 +494,7 @@ static inline void conn_free(struct connection *conn)
}
conn_force_unsubscribe(conn);
HA_SPIN_LOCK(OTHER_LOCK, &idle_conns[tid].takeover_lock);
MT_LIST_DEL((struct mt_list *)&conn->list);
HA_SPIN_UNLOCK(OTHER_LOCK, &idle_conns[tid].takeover_lock);
pool_free(pool_head_connection, conn);
}

53
src/server.c
View File

@ -5193,32 +5193,41 @@ struct task *srv_cleanup_toremove_connections(struct task *task, void *context,
return task;
}
/* Move toremove_nb connections from idle_list to toremove_list, -1 means
* moving them all.
* Returns the number of connections moved.
*/
static int srv_migrate_conns_to_remove(struct mt_list *idle_list, struct mt_list *toremove_list, int toremove_nb)
{
struct mt_list *elt1, elt2;
struct connection *conn;
int i = 0;
mt_list_for_each_entry_safe(conn, idle_list, list, elt1, elt2) {
if (toremove_nb != -1 && i >= toremove_nb)
break;
MT_LIST_DEL_SAFE_NOINIT(elt1);
MT_LIST_ADDQ_NOCHECK(toremove_list, &conn->list);
i++;
}
return i;
}
/* cleanup connections for a given server
* might be useful when going on forced maintenance or live changing ip/port
*/
static void srv_cleanup_connections(struct server *srv)
{
struct connection *conn;
int did_remove;
int i;
int j;
/* check all threads starting with ours */
HA_SPIN_LOCK(OTHER_LOCK, &idle_conn_srv_lock);
for (i = tid;;) {
did_remove = 0;
HA_SPIN_LOCK(OTHER_LOCK, &idle_conns[i].takeover_lock);
for (j = 0; j < srv->curr_idle_conns; j++) {
conn = MT_LIST_POP(&srv->idle_conns[i], struct connection *, list);
if (!conn)
conn = MT_LIST_POP(&srv->safe_conns[i],
struct connection *, list);
if (!conn)
break;
if (srv_migrate_conns_to_remove(&srv->idle_conns[i], &idle_conns[i].toremove_conns, -1) > 0)
did_remove = 1;
if (srv_migrate_conns_to_remove(&srv->safe_conns[i], &idle_conns[i].toremove_conns, -1) > 0)
did_remove = 1;
MT_LIST_ADDQ(&idle_conns[i].toremove_conns, (struct mt_list *)&conn->list);
}
HA_SPIN_UNLOCK(OTHER_LOCK, &idle_conns[i].takeover_lock);
if (did_remove)
task_wakeup(idle_conns[i].cleanup_task, TASK_WOKEN_OTHER);
@ -5287,18 +5296,14 @@ struct task *srv_cleanup_idle_connections(struct task *task, void *context, unsi
max_conn = (exceed_conns * srv->curr_idle_thr[i]) /
curr_idle + 1;
HA_SPIN_LOCK(OTHER_LOCK, &idle_conns[i].takeover_lock);
for (j = 0; j < max_conn; j++) {
struct connection *conn = MT_LIST_POP(&srv->idle_conns[i], struct connection *, list);
if (!conn)
conn = MT_LIST_POP(&srv->safe_conns[i],
struct connection *, list);
if (!conn)
break;
j = srv_migrate_conns_to_remove(&srv->idle_conns[i], &idle_conns[i].toremove_conns, max_conn);
if (j > 0)
did_remove = 1;
MT_LIST_ADDQ(&idle_conns[i].toremove_conns, (struct mt_list *)&conn->list);
}
HA_SPIN_UNLOCK(OTHER_LOCK, &idle_conns[i].takeover_lock);
if (max_conn - j > 0 &&
srv_migrate_conns_to_remove(&srv->safe_conns[i], &idle_conns[i].toremove_conns, max_conn - j) > 0)
did_remove = 1;
if (did_remove && max_conn < srv->curr_idle_thr[i])
srv_is_empty = 0;
if (did_remove)