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2881. [bug] Reduce the amount of time the rbtdb write lock

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is held when closing a version. [RT #21198]
This commit is contained in:
Mark Andrews
2010-05-10 01:39:03 +00:00
parent 36b08488a1
commit 121f783b66
3 changed files with 65 additions and 16 deletions
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3
CHANGES
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@@ -1,3 +1,6 @@
2881. [bug] Reduce the amount of time the rbtdb write lock
is held when closing a version. [RT #21198]
2880. [cleanup] Make the output of dnssec-keygen and dnssec-revoke
consistent. [RT #21078]

4
lib/dns/include/dns/events.h
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@@ -15,7 +15,7 @@
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: events.h,v 1.53 2009/09/01 00:22:26 jinmei Exp $ */
/* $Id: events.h,v 1.54 2010/05/10 01:39:03 marka Exp $ */
#ifndef DNS_EVENTS_H
#define DNS_EVENTS_H 1
@@ -58,7 +58,7 @@
#define DNS_EVENT_MASTERNEXTZONE (ISC_EVENTCLASS_DNS + 28)
#define DNS_EVENT_IOREADY (ISC_EVENTCLASS_DNS + 29)
#define DNS_EVENT_LOOKUPDONE (ISC_EVENTCLASS_DNS + 30)
/* #define DNS_EVENT_unused (ISC_EVENTCLASS_DNS + 31) */
#define DNS_EVENT_RBTDEADNODES (ISC_EVENTCLASS_DNS + 31)
#define DNS_EVENT_DISPATCHCONTROL (ISC_EVENTCLASS_DNS + 32)
#define DNS_EVENT_REQUESTCONTROL (ISC_EVENTCLASS_DNS + 33)
#define DNS_EVENT_DUMPQUANTUM (ISC_EVENTCLASS_DNS + 34)

74
lib/dns/rbtdb.c
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@@ -15,7 +15,7 @@
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: rbtdb.c,v 1.300 2010/02/26 00:18:06 marka Exp $ */
/* $Id: rbtdb.c,v 1.301 2010/05/10 01:39:03 marka Exp $ */
/*! \file */
@@ -2109,6 +2109,34 @@ setnsec3parameters(dns_db_t *db, rbtdb_version_t *version) {
}
#endif
static void
cleanup_dead_nodes_callback(isc_task_t *task, isc_event_t *event) {
dns_rbtdb_t *rbtdb = event->ev_arg;
isc_boolean_t again = ISC_FALSE;
unsigned int locknum;
unsigned int refs;
RBTDB_LOCK(&rbtdb->lock, isc_rwlocktype_write);
for (locknum = 0; locknum < rbtdb->node_lock_count; locknum++) {
NODE_LOCK(&rbtdb->node_locks[locknum].lock,
isc_rwlocktype_write);
cleanup_dead_nodes(rbtdb, locknum);
if (ISC_LIST_HEAD(rbtdb->deadnodes[locknum]) != NULL)
again = ISC_TRUE;
NODE_UNLOCK(&rbtdb->node_locks[locknum].lock,
isc_rwlocktype_write);
}
RBTDB_UNLOCK(&rbtdb->lock, isc_rwlocktype_write);
if (again)
isc_task_send(task, &event);
else {
isc_event_free(&event);
isc_refcount_decrement(&rbtdb->references, &refs);
if (refs == 0)
maybe_free_rbtdb(rbtdb);
}
}
static void
closeversion(dns_db_t *db, dns_dbversion_t **versionp, isc_boolean_t commit) {
dns_rbtdb_t *rbtdb = (dns_rbtdb_t *)db;
@@ -2309,15 +2337,28 @@ closeversion(dns_db_t *db, dns_dbversion_t **versionp, isc_boolean_t commit) {
}
if (!EMPTY(cleanup_list)) {
/*
* We acquire a tree write lock here in order to make sure
* that stale nodes will be removed in decrement_reference().
* If we didn't have the lock, those nodes could miss the
* chance to be removed until the server stops. The write lock
* is expensive, but this event should be rare enough to justify
* the cost.
*/
RWLOCK(&rbtdb->tree_lock, isc_rwlocktype_write);
isc_event_t *event = NULL;
isc_rwlocktype_t tlock = isc_rwlocktype_none;
if (rbtdb->task != NULL)
event = isc_event_allocate(rbtdb->common.mctx, NULL,
DNS_EVENT_RBTDEADNODES,
cleanup_dead_nodes_callback,
rbtdb, sizeof(isc_event_t));
if (event == NULL) {
/*
* We acquire a tree write lock here in order to make
* sure that stale nodes will be removed in
* decrement_reference(). If we didn't have the lock,
* those nodes could miss the chance to be removed
* until the server stops. The write lock is
* expensive, but this event should be rare enough
* to justify the cost.
*/
RWLOCK(&rbtdb->tree_lock, isc_rwlocktype_write);
tlock = isc_rwlocktype_write;
}
for (changed = HEAD(cleanup_list);
changed != NULL;
changed = next_changed) {
@@ -2332,20 +2373,25 @@ closeversion(dns_db_t *db, dns_dbversion_t **versionp, isc_boolean_t commit) {
* This is a good opportunity to purge any dead nodes,
* so use it.
*/
cleanup_dead_nodes(rbtdb, rbtnode->locknum);
if (event == NULL)
cleanup_dead_nodes(rbtdb, rbtnode->locknum);
if (rollback)
rollback_node(rbtnode, serial);
decrement_reference(rbtdb, rbtnode, least_serial,
isc_rwlocktype_write,
isc_rwlocktype_write, ISC_FALSE);
isc_rwlocktype_write, tlock,
ISC_FALSE);
NODE_UNLOCK(lock, isc_rwlocktype_write);
isc_mem_put(rbtdb->common.mctx, changed,
sizeof(*changed));
}
RWUNLOCK(&rbtdb->tree_lock, isc_rwlocktype_write);
if (event != NULL) {
isc_refcount_increment(&rbtdb->references, NULL);
isc_task_send(rbtdb->task, &event);
} else
RWUNLOCK(&rbtdb->tree_lock, isc_rwlocktype_write);
}
end: