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Merge branch 'ondrej/dns_rbtdb-locking-fixups' into 'main'

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Couple of small fixes in dns_rbtdb rwlock refactoring

See merge request isc-projects/bind9!7304
This commit is contained in:
Ondřej Surý 2023-01-07 06:15:07 +00:00
commit f0bba87db0
1 changed files with 61 additions and 144 deletions
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205
lib/dns/rbtdb.c
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@ -109,30 +109,33 @@ typedef uint32_t rbtdb_rdatatype_t;
#define RBTDB_LOCK(l, t) RWLOCK((l), (t))
#define RBTDB_UNLOCK(l, t) RWUNLOCK((l), (t))
typedef isc_rwlock_t nodelock_t;
#ifdef DNS_RBTDB_STRONG_RWLOCK_CHECK
#define STRONG_RWLOCK_CHECK(cond) REQUIRE(cond)
#else
#define STRONG_RWLOCK_CHECK(cond)
#endif
typedef isc_rwlock_t nodelock_t;
#define NODE_INITLOCK(l) isc_rwlock_init((l), 0, 0)
#define NODE_DESTROYLOCK(l) isc_rwlock_destroy(l)
#define NODE_LOCK(l, t, tp) \
{ \
REQUIRE(*tp == isc_rwlocktype_none); \
RWLOCK((l), (t)); \
*tp = t; \
#define NODE_LOCK(l, t, tp) \
{ \
STRONG_RWLOCK_CHECK(*tp == isc_rwlocktype_none); \
RWLOCK((l), (t)); \
*tp = t; \
}
#define NODE_UNLOCK(l, tp) \
{ \
STRONG_RWLOCK_CHECK(*tp != isc_rwlocktype_none); \
RWUNLOCK(l, *tp); \
*tp = isc_rwlocktype_none; \
}
#define NODE_RDLOCK(l, tp) NODE_LOCK(l, isc_rwlocktype_read, tp);
#define NODE_WRLOCK(l, tp) NODE_LOCK(l, isc_rwlocktype_write, tp);
#define NODE_UNLOCK(l, tp) \
{ \
REQUIRE(*tp != isc_rwlocktype_none); \
RWUNLOCK(l, *tp); \
*tp = isc_rwlocktype_none; \
}
#define NODE_TRYLOCK(l, t, tp) \
({ \
REQUIRE(*tp == isc_rwlocktype_none); \
STRONG_RWLOCK_CHECK(*tp == isc_rwlocktype_none); \
isc_result_t _result = isc_rwlock_trylock(l, t); \
if (_result == ISC_R_SUCCESS) { \
*tp = t; \
@ -143,35 +146,40 @@ typedef isc_rwlock_t nodelock_t;
#define NODE_TRYWRLOCK(l, tp) NODE_TRYLOCK(l, isc_rwlocktype_write, tp)
#define NODE_TRYUPGRADE(l, tp) \
({ \
REQUIRE(*tp == isc_rwlocktype_read); \
STRONG_RWLOCK_CHECK(*tp == isc_rwlocktype_read); \
isc_result_t _result = isc_rwlock_tryupgrade(l); \
if (_result == ISC_R_SUCCESS) { \
*tp = isc_rwlocktype_write; \
}; \
_result; \
})
#define NODE_FORCEUPGRADE(l, tp) \
if (NODE_TRYUPGRADE(l, tp) != ISC_R_SUCCESS) { \
NODE_UNLOCK(l, tp); \
NODE_WRLOCK(l, tp); \
}
typedef isc_rwlock_t treelock_t;
#define TREE_INITLOCK(l) isc_rwlock_init(l, 0, 0)
#define TREE_DESTROYLOCK(l) isc_rwlock_destroy(l)
#define TREE_LOCK(l, t, tp) \
{ \
REQUIRE(*tp == isc_rwlocktype_none); \
RWLOCK(l, t); \
*tp = t; \
#define TREE_LOCK(l, t, tp) \
{ \
STRONG_RWLOCK_CHECK(*tp == isc_rwlocktype_none); \
RWLOCK(l, t); \
*tp = t; \
}
#define TREE_UNLOCK(l, tp) \
{ \
STRONG_RWLOCK_CHECK(*tp != isc_rwlocktype_none); \
RWUNLOCK(l, *tp); \
*tp = isc_rwlocktype_none; \
}
#define TREE_RDLOCK(l, tp) TREE_LOCK(l, isc_rwlocktype_read, tp);
#define TREE_WRLOCK(l, tp) TREE_LOCK(l, isc_rwlocktype_write, tp);
#define TREE_UNLOCK(l, tp) \
{ \
REQUIRE(*tp != isc_rwlocktype_none); \
RWUNLOCK(l, *tp); \
*tp = isc_rwlocktype_none; \
}
#define TREE_TRYLOCK(l, t, tp) \
({ \
REQUIRE(*tp == isc_rwlocktype_none); \
STRONG_RWLOCK_CHECK(*tp == isc_rwlocktype_none); \
isc_result_t _result = isc_rwlock_trylock(l, t); \
if (_result == ISC_R_SUCCESS) { \
*tp = t; \
@ -182,92 +190,18 @@ typedef isc_rwlock_t treelock_t;
#define TREE_TRYWRLOCK(l, tp) TREE_TRYLOCK(l, isc_rwlocktype_write, tp)
#define TREE_TRYUPGRADE(l, tp) \
({ \
REQUIRE(*tp == isc_rwlocktype_read); \
STRONG_RWLOCK_CHECK(*tp == isc_rwlocktype_read); \
isc_result_t _result = isc_rwlock_tryupgrade(l); \
if (_result == ISC_R_SUCCESS) { \
*tp = isc_rwlocktype_write; \
}; \
_result; \
})
#else /* DNS_RBTDB_STRONG_RWLOCK_CHECK */
#define NODE_INITLOCK(l) isc_rwlock_init((l), 0, 0)
#define NODE_DESTROYLOCK(l) isc_rwlock_destroy(l)
#define NODE_LOCK(l, t, tp) \
{ \
RWLOCK((l), (t)); \
*tp = t; \
#define TREE_FORCEUPGRADE(l, tp) \
if (TREE_TRYUPGRADE(l, tp) != ISC_R_SUCCESS) { \
TREE_UNLOCK(l, tp); \
TREE_WRLOCK(l, tp); \
}
#define NODE_RDLOCK(l, tp) NODE_LOCK(l, isc_rwlocktype_read, tp);
#define NODE_WRLOCK(l, tp) NODE_LOCK(l, isc_rwlocktype_write, tp);
#define NODE_UNLOCK(l, tp) \
{ \
RWUNLOCK(l, *tp); \
*tp = isc_rwlocktype_none; \
}
#define NODE_TRYLOCK(l, t, tp) \
({ \
isc_result_t _result = isc_rwlock_trylock(l, t); \
if (_result == ISC_R_SUCCESS) { \
*tp = t; \
}; \
_result; \
})
#define NODE_TRYRDLOCK(l, tp) NODE_TRYLOCK(l, isc_rwlocktype_read, tp)
#define NODE_TRYWRLOCK(l, tp) NODE_TRYLOCK(l, isc_rwlocktype_write, tp)
#define NODE_TRYUPGRADE(l, tp) \
({ \
isc_result_t _result = isc_rwlock_tryupgrade(l); \
if (_result == ISC_R_SUCCESS) { \
*tp = isc_rwlocktype_write; \
}; \
_result; \
})
typedef isc_rwlock_t treelock_t;
#define TREE_INITLOCK(l) isc_rwlock_init(l, 0, 0)
#define TREE_DESTROYLOCK(l) isc_rwlock_destroy(l)
#define TREE_LOCK(l, t, tp) \
{ \
RWLOCK(l, t); \
*tp = t; \
}
#define TREE_RDLOCK(l, tp) \
{ \
TREE_LOCK(l, isc_rwlocktype_read, tp); \
}
#define TREE_WRLOCK(l, tp) \
{ \
TREE_LOCK(l, isc_rwlocktype_write, tp); \
}
#define TREE_UNLOCK(l, tp) \
{ \
RWUNLOCK(l, *tp); \
*tp = isc_rwlocktype_none; \
}
#define TREE_TRYLOCK(l, t, tp) \
({ \
isc_result_t _result = isc_rwlock_trylock(l, t); \
if (_result == ISC_R_SUCCESS) { \
*tp = t; \
}; \
_result; \
})
#define TREE_TRYRDLOCK(l, tp) TREE_TRYLOCK(l, isc_rwlocktype_read, tp)
#define TREE_TRYWRLOCK(l, tp) TREE_TRYLOCK(l, isc_rwlocktype_write, tp)
#define TREE_TRYUPGRADE(l, tp) \
({ \
isc_result_t _result = isc_rwlock_tryupgrade(l); \
if (_result == ISC_R_SUCCESS) { \
*tp = isc_rwlocktype_write; \
}; \
_result; \
})
#endif
/*%
* Whether to rate-limit updating the LRU to avoid possible thread contention.
@ -686,7 +620,8 @@ static void
update_header(dns_rbtdb_t *rbtdb, rdatasetheader_t *header, isc_stdtime_t now);
static void
expire_header(dns_rbtdb_t *rbtdb, rdatasetheader_t *header,
isc_rwlocktype_t *tlocktypep, expire_t reason);
isc_rwlocktype_t *nlocktypep, isc_rwlocktype_t *tlocktypep,
expire_t reason);
static void
overmem_purge(dns_rbtdb_t *rbtdb, unsigned int locknum_start, isc_stdtime_t now,
isc_rwlocktype_t *tlocktypep);
@ -2041,10 +1976,7 @@ reactivate_node(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
/*
* Upgrade the lock and test if we still need to unlink.
*/
if (NODE_TRYUPGRADE(nodelock, &nlocktype) != ISC_R_SUCCESS) {
NODE_UNLOCK(nodelock, &nlocktype);
NODE_WRLOCK(nodelock, &nlocktype);
}
NODE_FORCEUPGRADE(nodelock, &nlocktype);
POST(nlocktype);
if (ISC_LINK_LINKED(node, deadlink)) {
ISC_LIST_UNLINK(rbtdb->deadnodes[node->locknum], node,
@ -2108,12 +2040,7 @@ decrement_reference(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,
/* Upgrade the lock? */
if (*nlocktypep == isc_rwlocktype_read) {
if (NODE_TRYUPGRADE(&nodelock->lock, nlocktypep) !=
ISC_R_SUCCESS)
{
NODE_UNLOCK(&nodelock->lock, nlocktypep);
NODE_WRLOCK(&nodelock->lock, nlocktypep);
}
NODE_FORCEUPGRADE(&nodelock->lock, nlocktypep);
}
if (isc_refcount_decrement(&node->references) > 1) {
@ -2871,12 +2798,7 @@ findnodeintree(dns_rbtdb_t *rbtdb, dns_rbt_t *tree, const dns_name_t *name,
/*
* Try to upgrade the lock and if that fails unlock then relock.
*/
if (TREE_TRYUPGRADE(&rbtdb->tree_lock, &tlocktype) !=
ISC_R_SUCCESS)
{
TREE_UNLOCK(&rbtdb->tree_lock, &tlocktype);
TREE_WRLOCK(&rbtdb->tree_lock, &tlocktype);
}
TREE_FORCEUPGRADE(&rbtdb->tree_lock, &tlocktype);
node = NULL;
result = dns_rbt_addnode(tree, name, &node);
if (result == ISC_R_SUCCESS) {
@ -4871,12 +4793,7 @@ find_deepest_zonecut(rbtdb_search_t *search, dns_rbtnode_t *node,
need_headerupdate(foundsig, search->now)))
{
if (nlocktype != isc_rwlocktype_write) {
if (NODE_TRYUPGRADE(lock, &nlocktype) !=
ISC_R_SUCCESS)
{
NODE_UNLOCK(lock, &nlocktype);
NODE_WRLOCK(lock, &nlocktype);
}
NODE_FORCEUPGRADE(lock, &nlocktype);
POST(nlocktype);
}
if (need_headerupdate(found, search->now)) {
@ -5391,10 +5308,7 @@ node_exit:
if ((update != NULL || updatesig != NULL) &&
nlocktype != isc_rwlocktype_write)
{
if (NODE_TRYUPGRADE(lock, &nlocktype) != ISC_R_SUCCESS) {
NODE_UNLOCK(lock, &nlocktype);
NODE_WRLOCK(lock, &nlocktype);
}
NODE_FORCEUPGRADE(lock, &nlocktype);
POST(nlocktype);
}
if (update != NULL && need_headerupdate(update, search.now)) {
@ -5574,11 +5488,7 @@ cache_findzonecut(dns_db_t *db, const dns_name_t *name, unsigned int options,
(foundsig != NULL && need_headerupdate(foundsig, search.now)))
{
if (nlocktype != isc_rwlocktype_write) {
if (NODE_TRYUPGRADE(lock, &nlocktype) != ISC_R_SUCCESS)
{
NODE_UNLOCK(lock, &nlocktype);
NODE_WRLOCK(lock, &nlocktype);
}
NODE_FORCEUPGRADE(lock, &nlocktype);
POST(nlocktype);
}
if (need_headerupdate(found, search.now)) {
@ -7083,7 +6993,8 @@ addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
header->rdh_ttl + STALE_TTL(header, rbtdb) <
now - RBTDB_VIRTUAL)
{
expire_header(rbtdb, header, &tlocktype, expire_ttl);
expire_header(rbtdb, header, &nlocktype, &tlocktype,
expire_ttl);
}
/*
@ -8799,11 +8710,13 @@ rdataset_expire(dns_rdataset_t *rdataset) {
dns_rbtnode_t *rbtnode = rdataset->private2;
rdatasetheader_t *header = rdataset->private3;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlocktype_t tlocktype = isc_rwlocktype_none;
header--;
NODE_WRLOCK(&rbtdb->node_locks[rbtnode->locknum].lock, &nlocktype);
expire_header(rbtdb, header, false, expire_flush);
expire_header(rbtdb, header, &nlocktype, &tlocktype, expire_flush);
NODE_UNLOCK(&rbtdb->node_locks[rbtnode->locknum].lock, &nlocktype);
INSIST(tlocktype == isc_rwlocktype_none);
}
static void
@ -10175,7 +10088,8 @@ overmem_purge(dns_rbtdb_t *rbtdb, unsigned int locknum_start, isc_stdtime_t now,
header = isc_heap_element(rbtdb->heaps[locknum], 1);
if (header && header->rdh_ttl < now - RBTDB_VIRTUAL) {
expire_header(rbtdb, header, tlocktypep, expire_ttl);
expire_header(rbtdb, header, &nlocktype, tlocktypep,
expire_ttl);
purgecount--;
}
@ -10192,7 +10106,8 @@ overmem_purge(dns_rbtdb_t *rbtdb, unsigned int locknum_start, isc_stdtime_t now,
*/
ISC_LIST_UNLINK(rbtdb->rdatasets[locknum], header,
link);
expire_header(rbtdb, header, tlocktypep, expire_lru);
expire_header(rbtdb, header, &nlocktype, tlocktypep,
expire_lru);
purgecount--;
}
@ -10202,13 +10117,15 @@ overmem_purge(dns_rbtdb_t *rbtdb, unsigned int locknum_start, isc_stdtime_t now,
static void
expire_header(dns_rbtdb_t *rbtdb, rdatasetheader_t *header,
isc_rwlocktype_t *tlocktypep, expire_t reason) {
isc_rwlocktype_t *nlocktypep, isc_rwlocktype_t *tlocktypep,
expire_t reason) {
set_ttl(rbtdb, header, 0);
mark_header_ancient(rbtdb, header);
/*
* Caller must hold the node (write) lock.
*/
INSIST(*nlocktypep == isc_rwlocktype_write);
if (isc_refcount_current(&header->node->references) == 0) {
isc_rwlocktype_t nlocktype = isc_rwlocktype_write;