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Refactor node reference counting in rbtdb.c

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Refactor the pattern in the newref() and decref() functions in rbtdb.c
following the pattern, so it follows the similar pattern we already have
for QPDB.
This commit is contained in:
Ondřej Surý
2025-01-30 17:48:34 +01:00
parent 5300eebc9e
commit 9c45de9473
1 changed files with 57 additions and 62 deletions
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111
lib/dns/rbtdb.c
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@@ -1115,30 +1115,19 @@ delete_node(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node) {
} }
} }
/* static void
* Caller must be holding the node lock. rbtnode_newref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node DNS__DB_FLARG) {
*/ uint_fast32_t refs = isc_refcount_increment0(&node->references);
void
dns__rbtdb_newref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
isc_rwlocktype_t nlocktype DNS__DB_FLARG) {
uint_fast32_t refs;
if (nlocktype == isc_rwlocktype_write &&
ISC_LINK_LINKED(node, deadlink))
{
ISC_LIST_UNLINK(rbtdb->deadnodes[node->locknum], node,
deadlink);
}
refs = isc_refcount_increment0(&node->references);
#if DNS_DB_NODETRACE #if DNS_DB_NODETRACE
fprintf(stderr, "incr:node:%s:%s:%u:%p->references = %" PRIuFAST32 "\n", fprintf(stderr, "incr:node:%s:%s:%u:%p->references = %" PRIuFAST32 "\n",
func, file, line, node, refs + 1); func, file, line, node, refs + 1);
#else
UNUSED(refs);
#endif #endif
if (refs == 0) { if (refs > 0) {
return;
}
/* this is the first reference to the node */ /* this is the first reference to the node */
refs = isc_refcount_increment0( refs = isc_refcount_increment0(
&rbtdb->node_locks[node->locknum].references); &rbtdb->node_locks[node->locknum].references);
@@ -1146,12 +1135,27 @@ dns__rbtdb_newref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
fprintf(stderr, fprintf(stderr,
"incr:nodelock:%s:%s:%u:%p:%p->references = " "incr:nodelock:%s:%s:%u:%p:%p->references = "
"%" PRIuFAST32 "\n", "%" PRIuFAST32 "\n",
func, file, line, node, func, file, line, node, &rbtdb->node_locks[node->locknum],
&rbtdb->node_locks[node->locknum], refs + 1); refs + 1);
#else #else
UNUSED(refs); UNUSED(refs);
#endif #endif
} }
/*
* Caller must be holding the node lock.
*/
void
dns__rbtdb_newref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
isc_rwlocktype_t nlocktype DNS__DB_FLARG) {
if (nlocktype == isc_rwlocktype_write &&
ISC_LINK_LINKED(node, deadlink))
{
ISC_LIST_UNLINK(rbtdb->deadnodes[node->locknum], node,
deadlink);
}
rbtnode_newref(rbtdb, node);
} }
/*% /*%
@@ -1280,6 +1284,29 @@ reactivate_node(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
NODE_UNLOCK(nodelock, &nlocktype); NODE_UNLOCK(nodelock, &nlocktype);
} }
static bool
rbtnode_decref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node DNS__DB_FLARG) {
db_nodelock_t *nodelock = &rbtdb->node_locks[node->locknum];
uint_fast32_t refs = isc_refcount_decrement(&node->references);
#if DNS_DB_NODETRACE
fprintf(stderr, "decr:node:%s:%s:%u:%p->references = %" PRIuFAST32 "\n",
func, file, line, node, refs - 1);
#endif
if (refs > 1) {
return false;
}
refs = isc_refcount_decrement(&nodelock->references);
#if DNS_DB_NODETRACE
fprintf(stderr,
"decr:nodelock:%s:%s:%u:%p:%p->references = "
"%" PRIuFAST32 "\n",
func, file, line, node, nodelock, refs - 1);
#else
UNUSED(refs);
#endif
return true;
}
/* /*
* Caller must be holding the node lock; either the read or write lock. * Caller must be holding the node lock; either the read or write lock.
* Note that the lock must be held even when node references are * Note that the lock must be held even when node references are
@@ -1302,10 +1329,8 @@ dns__rbtdb_decref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
isc_result_t result; isc_result_t result;
bool locked = *tlocktypep != isc_rwlocktype_none; bool locked = *tlocktypep != isc_rwlocktype_none;
bool write_locked = false; bool write_locked = false;
int bucket = node->locknum; db_nodelock_t *nodelock = &rbtdb->node_locks[node->locknum];
db_nodelock_t *nodelock = &rbtdb->node_locks[bucket];
bool no_reference = true; bool no_reference = true;
uint_fast32_t refs;
REQUIRE(*nlocktypep != isc_rwlocktype_none); REQUIRE(*nlocktypep != isc_rwlocktype_none);
@@ -1313,24 +1338,10 @@ dns__rbtdb_decref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
((n)->data != NULL || ((l) && (n)->down != NULL) || \ ((n)->data != NULL || ((l) && (n)->down != NULL) || \
(n) == (r)->origin_node || (n) == (r)->nsec3_origin_node) (n) == (r)->origin_node || (n) == (r)->nsec3_origin_node)
/* Handle easy and/or typical case first. */ if (!rbtnode_decref(rbtdb, node DNS__DB_FLARG_PASS)) {
refs = isc_refcount_decrement(&node->references);
#if DNS_DB_NODETRACE
fprintf(stderr, "decr:node:%s:%s:%u:%p->references = %" PRIuFAST32 "\n",
func, file, line, node, refs - 1);
#endif
if (refs > 1) {
return false; return false;
} }
refs = isc_refcount_decrement(&nodelock->references);
#if DNS_DB_NODETRACE
fprintf(stderr,
"decr:nodelock:%s:%s:%u:%p:%p->references = "
"%" PRIuFAST32 "\n",
func, file, line, node, nodelock, refs - 1);
#else
UNUSED(refs);
#endif
if (!node->dirty && KEEP_NODE(node, rbtdb, locked)) { if (!node->dirty && KEEP_NODE(node, rbtdb, locked)) {
return true; return true;
} }
@@ -1340,21 +1351,14 @@ dns__rbtdb_decref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
* node. To clean it up, the node ref needs to decrement to 0 under the * node. To clean it up, the node ref needs to decrement to 0 under the
* node write lock, so we regain the ref and try again. * node write lock, so we regain the ref and try again.
*/ */
dns__rbtdb_newref(rbtdb, node, *nlocktypep DNS__DB_FLARG_PASS); rbtnode_newref(rbtdb, node DNS__DB_FLARG_PASS);
/* Upgrade the lock? */ /* Upgrade the lock? */
if (*nlocktypep == isc_rwlocktype_read) { if (*nlocktypep == isc_rwlocktype_read) {
NODE_FORCEUPGRADE(&nodelock->lock, nlocktypep); NODE_FORCEUPGRADE(&nodelock->lock, nlocktypep);
} }
refs = isc_refcount_decrement(&node->references); if (!rbtnode_decref(rbtdb, node DNS__DB_FLARG_PASS)) {
#if DNS_DB_NODETRACE
fprintf(stderr, "decr:node:%s:%s:%u:%p->references = %" PRIuFAST32 "\n",
func, file, line, node, refs - 1);
#else
UNUSED(refs);
#endif
if (refs > 1) {
return false; return false;
} }
@@ -1407,15 +1411,6 @@ dns__rbtdb_decref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
write_locked = true; write_locked = true;
} }
refs = isc_refcount_decrement(&nodelock->references);
#if DNS_DB_NODETRACE
fprintf(stderr,
"decr:nodelock:%s:%s:%u:%p:%p->references = %" PRIuFAST32 "\n",
func, file, line, node, nodelock, refs - 1);
#else
UNUSED(refs);
#endif
if (KEEP_NODE(node, rbtdb, locked || write_locked)) { if (KEEP_NODE(node, rbtdb, locked || write_locked)) {
goto restore_locks; goto restore_locks;
} }
@@ -1455,7 +1450,7 @@ dns__rbtdb_decref(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
} else { } else {
INSIST(node->data == NULL); INSIST(node->data == NULL);
if (!ISC_LINK_LINKED(node, deadlink)) { if (!ISC_LINK_LINKED(node, deadlink)) {
ISC_LIST_APPEND(rbtdb->deadnodes[bucket], node, ISC_LIST_APPEND(rbtdb->deadnodes[node->locknum], node,
deadlink); deadlink);
} }
} }