more temporary probing

a minor bit of code refactoring - the 'node' argument wasn't
being used; it was just being treated as a local variable.

lib/dns/Makefile.am

@@ -342,8 +342,8 @@ libdns_la_LIBADD += $(LMDB_LIBS)
 endif
 
 if !HAVE_SYSTEMTAP
-DTRACE_DEPS = libdns_la-xfrin.lo
-DTRACE_OBJS = .libs/libdns_la-xfrin.$(OBJEXT)
+DTRACE_DEPS = libdns_la-xfrin.lo libdns_la-qpcache.lo
+DTRACE_OBJS = .libs/libdns_la-xfrin.$(OBJEXT) .libs/libdns_la-qpcache.$(OBJEXT)
 endif
 
 include $(top_srcdir)/Makefile.dtrace

lib/dns/include/dns/rdataslab.h

@@ -75,7 +75,7 @@ struct dns_slabheader {
 	dns_ttl_t	      ttl;
 	dns_typepair_t	      type;
 	atomic_uint_least16_t attributes;
-	dns_trust_t	      trust;
+	atomic_uint_fast16_t  trust;
 
 	unsigned int heap_index;
 	/*%<

lib/dns/probes.d

@@ -27,4 +27,7 @@ provider libdns {
 	probe xfrin_recv_try_axfr(void *, char *, int);
 	probe xfrin_sent(void *, char *, int);
 	probe xfrin_start(void *, char *);
+
+	probe qpcache_addrdataset_done(void *, uint32_t, bool overmem);
+	probe qpcache_addrdataset_start(void *, uint32_t);
 };

lib/dns/qp.c

@@ -1058,7 +1058,7 @@ dns_qpmulti_memusage(dns_qpmulti_t *multi) {
 
 	dns_qp_memusage_t memusage = dns_qp_memusage(qp);
 
-	if (qp->transaction_mode == QP_UPDATE) {
+	if (qp->transaction_mode == QP_UPDATE && qp->usage != NULL) {
 		memusage.bytes -= QP_CHUNK_BYTES;
 		memusage.bytes += qp->usage[qp->bump].used *
 				  sizeof(dns_qpnode_t);

lib/dns/qp_p.h

@@ -141,7 +141,7 @@ enum {
 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 #define QP_CHUNK_LOG 7
 #else
-#define QP_CHUNK_LOG 10
+#define QP_CHUNK_LOG 12
 #endif
 
 STATIC_ASSERT(6 <= QP_CHUNK_LOG && QP_CHUNK_LOG <= 20,

lib/dns/rdataslab.c

@@ -1407,9 +1407,7 @@ static void
 rdataset_settrust(dns_rdataset_t *rdataset, dns_trust_t trust) {
 	dns_slabheader_t *header = dns_slabheader_fromrdataset(rdataset);
 
-	dns_db_locknode(header->db, header->node, isc_rwlocktype_write);
 	header->trust = rdataset->trust = trust;
-	dns_db_unlocknode(header->db, header->node, isc_rwlocktype_write);
 }
 
 static void

lib/dns/resolver.c

@@ -5190,7 +5190,7 @@ validated(void *arg) {
 			result = ISC_R_NOTFOUND;
 			if (val->rdataset != NULL) {
 				result = dns_db_findnode(fctx->cache, val->name,
-							 true, &node);
+							 false, &node);
 			}
 			if (result == ISC_R_SUCCESS) {
 				(void)dns_db_deleterdataset(fctx->cache, node,
@@ -5815,7 +5815,6 @@ cache_name(fetchctx_t *fctx, dns_name_t *name, dns_message_t *message,
 	/*
 	 * Find or create the cache node.
 	 */
-	node = NULL;
 	result = dns_db_findnode(fctx->cache, name, true, &node);
 	if (result != ISC_R_SUCCESS) {
 		return (result);

lib/isc/Makefile.am

@@ -260,8 +260,8 @@ libisc_la_LIBADD +=		\
 endif HAVE_LIBXML2
 
 if !HAVE_SYSTEMTAP
-DTRACE_DEPS = libisc_la-rwlock.lo libisc_la-job.lo
-DTRACE_OBJS = .libs/libisc_la-rwlock.$(OBJEXT) .libs/libisc_la-job.$(OBJEXT)
+DTRACE_DEPS = libisc_la-rwlock.lo libisc_la-job.lo libisc_la-loop.lo
+DTRACE_OBJS = .libs/libisc_la-rwlock.$(OBJEXT) .libs/libisc_la-job.$(OBJEXT) .libs/libisc_la-loop.$(OBJEXT)
 endif
 
 include $(top_srcdir)/Makefile.dtrace

lib/isc/include/isc/loop.h

@@ -225,4 +225,14 @@ isc_loop_shuttingdown(isc_loop_t *loop);
  *
  * \li 'loop' is a valid loop and the loop tid matches the current tid.
  */
+
+void
+isc_loop_rcu_barrier(isc_loop_t *loop);
+/*%<
+ * Triggers an rcu_barrier() call at the end of the current loop tick.
+ *
+ * Requires:
+ *
+ * \li 'loop' is a valid loop and the loop tid matches the current tid.
+ */
 ISC_LANG_ENDDECLS

lib/isc/loop.c

@@ -41,6 +41,7 @@
 #include "async_p.h"
 #include "job_p.h"
 #include "loop_p.h"
+#include "probes.h"
 
 /**
  * Private
@@ -236,7 +237,9 @@ loop_init(isc_loop_t *loop, isc_loopmgr_t *loopmgr, uint32_t tid) {
 
 static void
 quiescent_cb(uv_prepare_t *handle) {
-	UNUSED(handle);
+	isc_loop_t *loop = uv_handle_get_data(handle);
+
+	LIBISC_LOOP_QUIESCENT_CB_START(loop, loop->rcu_barrier);
 
 #if defined(RCU_QSBR)
 	/* safe memory reclamation */
@@ -247,6 +250,12 @@ quiescent_cb(uv_prepare_t *handle) {
 #else
 	INSIST(!rcu_read_ongoing());
 #endif
+
+	if (loop->rcu_barrier) {
+		rcu_barrier();
+	}
+
+	LIBISC_LOOP_QUIESCENT_CB_DONE(loop, loop->rcu_barrier);
 }
 
 static void
@@ -624,3 +633,11 @@ isc_loop_shuttingdown(isc_loop_t *loop) {
 
 	return (loop->shuttingdown);
 }
+
+void
+isc_loop_rcu_barrier(isc_loop_t *loop) {
+	REQUIRE(VALID_LOOP(loop));
+	REQUIRE(loop->tid == isc_tid());
+
+	loop->rcu_barrier = true;
+}

lib/isc/loop_p.h

@@ -76,6 +76,8 @@ struct isc_loop {
 
 	/* safe memory reclamation */
 	uv_prepare_t quiescent;
+
+	bool rcu_barrier;
 };
 
 /*

lib/isc/probes.d

@@ -27,4 +27,7 @@ provider libisc {
 	probe rwlock_wrlock_acq(void *);
 	probe rwlock_wrlock_req(void *);
 	probe rwlock_wrunlock(void *);
+
+	probe loop_quiescent_cb_done(void *, bool);
+	probe loop_quiescent_cb_start(void *, bool);
 };