Optimize dist entry management

1 files changed, 234 insertions, 82 deletions

diff --git a/erts/emulator/beam/erl_node_tables.c b/erts/emulator/beam/erl_node_tables.c
index 4ef1d54906..dd1b6b2cc8 100644
--- a/erts/emulator/beam/erl_node_tables.c
+++ b/erts/emulator/beam/erl_node_tables.c
@@ -29,6 +29,8 @@
 #include "error.h"
 #include "erl_thr_progress.h"
 #include "dtrace-wrapper.h"
+#include "erl_binary.h"
+#include "erl_bif_unique.h"
 
 Hash erts_dist_table;
 Hash erts_node_table;
@@ -57,6 +59,58 @@ static ErtsMonotonicTime node_tab_delete_delay;
 
 /* -- The distribution table ---------------------------------------------- */
 
+#define ErtsBin2DistEntry(B) \
+    ((DistEntry *) ERTS_MAGIC_BIN_DATA((B)))
+#define ErtsDistEntry2Bin(DEP) \
+    ((Binary *) ERTS_MAGIC_BIN_FROM_DATA((DEP)))
+
+static ERTS_INLINE erts_aint_t
+de_refc_read(DistEntry *dep, erts_aint_t min)
+{
+    return erts_refc_read(&ErtsDistEntry2Bin(dep)->intern.refc, min);
+}
+
+static ERTS_INLINE erts_aint_t
+de_refc_inc_read(DistEntry *dep, erts_aint_t min)
+{
+    return erts_refc_inctest(&ErtsDistEntry2Bin(dep)->intern.refc, min);
+}
+
+static ERTS_INLINE void
+de_refc_inc(DistEntry *dep, erts_aint_t min)
+{
+    erts_refc_inc(&ErtsDistEntry2Bin(dep)->intern.refc, min);
+}
+
+static ERTS_INLINE void
+de_refc_dec(DistEntry *dep, erts_aint_t min)
+{
+#ifdef DEBUG
+    (void) erts_refc_read(&ErtsDistEntry2Bin(dep)->intern.refc, min+1);
+#endif
+    erts_bin_release(ErtsDistEntry2Bin(dep));
+}
+
+static ERTS_INLINE erts_aint_t
+de_refc_dec_read(DistEntry *dep, erts_aint_t min)
+{
+    return erts_refc_dectest(&ErtsDistEntry2Bin(dep)->intern.refc, min);
+}
+
+void
+erts_ref_dist_entry(DistEntry *dep)
+{
+    ASSERT(dep);
+    de_refc_inc(dep, 1);
+}
+
+void
+erts_deref_dist_entry(DistEntry *dep)
+{
+    ASSERT(dep);
+    de_refc_dec(dep, 0);
+}
+
 #ifdef DEBUG
 static int
 is_in_de_list(DistEntry *dep, DistEntry *dep_list)
@@ -85,20 +139,36 @@ dist_table_cmp(void *dep1, void *dep2)
 static void*
 dist_table_alloc(void *dep_tmpl)
 {
+#ifdef DEBUG
+    erts_aint_t refc;
+#endif
     Eterm chnl_nr;
     Eterm sysname;
+    Binary *bin;
     DistEntry *dep;
     erts_smp_rwmtx_opt_t rwmtx_opt = ERTS_SMP_RWMTX_OPT_DEFAULT_INITER;
     rwmtx_opt.type = ERTS_SMP_RWMTX_TYPE_FREQUENT_READ;
 
     sysname = ((DistEntry *) dep_tmpl)->sysname;
     chnl_nr = make_small((Uint) atom_val(sysname));
-    dep = (DistEntry *) erts_alloc(ERTS_ALC_T_DIST_ENTRY, sizeof(DistEntry));
+
+    bin = erts_create_magic_binary_x(sizeof(DistEntry),
+                                     erts_dist_entry_destructor,
+                                     ERTS_ALC_T_DIST_ENTRY,
+                                     0);
+    dep = ErtsBin2DistEntry(bin);
 
     dist_entries++;
 
+#ifdef DEBUG
+    refc =
+#else
+    (void)
+#endif
+        de_refc_dec_read(dep, -1);
+    ASSERT(refc == -1);
+
     dep->prev				= NULL;
-    erts_smp_refc_init(&dep->refc, -1);
     erts_smp_rwmtx_init_opt_x(&dep->rwmtx, &rwmtx_opt, "dist_entry", chnl_nr);
     dep->sysname			= sysname;
     dep->cid				= NIL;
@@ -185,7 +255,7 @@ dist_table_free(void *vdep)
 #ifdef DEBUG
     sys_memset(vdep, 0x77, sizeof(DistEntry));
 #endif
-    erts_free(ERTS_ALC_T_DIST_ENTRY, (void *) dep);
+    erts_bin_free(ErtsDistEntry2Bin(dep));
 
     ASSERT(dist_entries > 0);
     dist_entries--;
@@ -203,19 +273,52 @@ erts_dist_table_info(fmtfn_t to, void *to_arg)
 	erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
 }
 
+static ERTS_INLINE DistEntry *find_dist_entry(Eterm sysname,
+                                              int inc_refc,
+                                              int connected_only)
+{
+    DistEntry *res;
+    DistEntry de;
+    de.sysname = sysname;
+    erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
+    res = hash_get(&erts_dist_table, (void *) &de);
+    if (res) {
+        if (connected_only && is_nil(res->cid))
+            res = NULL;
+        else {
+            int pend_delete;
+            erts_aint_t refc;
+            if (inc_refc) {
+                refc = de_refc_inc_read(res, 1);
+                pend_delete = refc < 2;
+            }
+            else {
+                refc = de_refc_read(res, 0);
+                pend_delete = refc < 1;
+            }
+            if (pend_delete) /* Pending delete */
+                de_refc_inc(res, 1);
+        }
+    }
+    erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
+    return res;
+}
+
 DistEntry *
 erts_channel_no_to_dist_entry(Uint cno)
 {
+    /*
+     * Does NOT increase reference count!
+     */
+
 /*
  * For this node (and previous incarnations of this node),
  * ERST_INTERNAL_CHANNEL_NO (will always be 0 I guess) is used as
  * channel no. For other nodes, the atom index of the atom corresponding
  * to the node name is used as channel no.
  */
-    if(cno == ERST_INTERNAL_CHANNEL_NO) {
-	erts_smp_refc_inc(&erts_this_dist_entry->refc, 2);
+    if (cno == ERST_INTERNAL_CHANNEL_NO)
 	return erts_this_dist_entry;
-    }
 
     if((cno > MAX_ATOM_INDEX)
        || (cno >= atom_table_size())
@@ -224,80 +327,97 @@ erts_channel_no_to_dist_entry(Uint cno)
         
     /* cno is a valid atom index; find corresponding dist entry (if there
        is one) */
-    return erts_find_dist_entry(make_atom(cno));
+    return find_dist_entry(make_atom(cno), 0, 0);
 }
 
-
 DistEntry *
 erts_sysname_to_connected_dist_entry(Eterm sysname)
 {
-    DistEntry de;
-    DistEntry *res_dep;
-    de.sysname = sysname;
-  
-    if(erts_this_dist_entry->sysname == sysname) {
-	erts_smp_refc_inc(&erts_this_dist_entry->refc, 2);
+    /*
+     * Does NOT increase reference count!
+     */
+    if(erts_this_dist_entry->sysname == sysname)
 	return erts_this_dist_entry;
-    }
-
-    erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
-    res_dep = (DistEntry *) hash_get(&erts_dist_table, (void *) &de);
-    if (res_dep) {
-	erts_aint_t refc = erts_smp_refc_inctest(&res_dep->refc, 1);
-	if (refc < 2) /* Pending delete */
-	    erts_smp_refc_inc(&res_dep->refc, 1);
-    }
-    erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
-    if (res_dep) {
-	int deref;
-	erts_smp_rwmtx_rlock(&res_dep->rwmtx);
-	deref = is_nil(res_dep->cid);
-	erts_smp_rwmtx_runlock(&res_dep->rwmtx);
-	if (deref) {
-	    erts_deref_dist_entry(res_dep);
-	    res_dep = NULL;
-	}
-    }
-    return res_dep;
+    return find_dist_entry(sysname, 0, 1);
 }
 
 DistEntry *erts_find_or_insert_dist_entry(Eterm sysname)
 {
+    /*
+     * This function DOES increase reference count!
+     */
     DistEntry *res;
     DistEntry de;
     erts_aint_t refc;
-    res = erts_find_dist_entry(sysname);
+    res = find_dist_entry(sysname, 1, 0);
     if (res)
 	return res;
     de.sysname = sysname;
     erts_smp_rwmtx_rwlock(&erts_dist_table_rwmtx);
     res = hash_put(&erts_dist_table, (void *) &de);
-    refc = erts_smp_refc_inctest(&res->refc, 0);
+    refc = de_refc_inc_read(res, 0);
     if (refc < 2) /* New or pending delete */
-	erts_smp_refc_inc(&res->refc, 1);
+        de_refc_inc(res, 1);
     erts_smp_rwmtx_rwunlock(&erts_dist_table_rwmtx);
     return res;
 }
 
 DistEntry *erts_find_dist_entry(Eterm sysname)
 {
-    DistEntry *res;
-    DistEntry de;
-    de.sysname = sysname;
-    erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
-    res = hash_get(&erts_dist_table, (void *) &de);
-    if (res) {
-	erts_aint_t refc = erts_smp_refc_inctest(&res->refc, 1);
-	if (refc < 2) /* Pending delete */
-	    erts_smp_refc_inc(&res->refc, 1);
-    }
-    erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
-    return res;
+    /*
+     * Does NOT increase reference count!
+     */
+    return find_dist_entry(sysname, 0, 0);
 }
 
-static void try_delete_dist_entry(void *vdep)
+DistEntry *
+erts_dhandle_to_dist_entry(Eterm dhandle)
 {
-    DistEntry *dep = (DistEntry *) vdep;
+    Binary *bin;
+    if (!is_internal_magic_ref(dhandle))
+        return NULL;
+    bin = erts_magic_ref2bin(dhandle);
+    if (ERTS_MAGIC_BIN_DESTRUCTOR(bin) != erts_dist_entry_destructor)
+        return NULL;
+    return ErtsBin2DistEntry(bin);
+}
+
+Eterm
+erts_make_dhandle(Process *c_p, DistEntry *dep)
+{
+    Binary *bin;
+    Eterm *hp;
+
+    bin = ErtsDistEntry2Bin(dep);
+    ASSERT(bin);
+    ASSERT(ERTS_MAGIC_BIN_DESTRUCTOR(bin) == erts_dist_entry_destructor);
+    hp = HAlloc(c_p, ERTS_MAGIC_REF_THING_SIZE);
+    return erts_mk_magic_ref(&hp, &c_p->off_heap, bin);
+}
+
+static void try_delete_dist_entry(void *vbin);
+
+static void
+prepare_try_delete_dist_entry(void *vbin)
+{
+    Binary *bin = (Binary *) vbin;
+    DistEntry *dep = ErtsBin2DistEntry(bin);
+    Uint size;
+    erts_aint_t refc;
+
+    refc = de_refc_read(dep, 0);
+    if (refc > 0)
+        return;
+
+    size = ERTS_MAGIC_BIN_SIZE(sizeof(DistEntry));
+    erts_schedule_thr_prgr_later_cleanup_op(try_delete_dist_entry,
+                                            vbin, &dep->later_op, size);
+}
+
+static void try_delete_dist_entry(void *vbin)
+{
+    Binary *bin = (Binary *) vbin;
+    DistEntry *dep = ErtsBin2DistEntry(bin);
     erts_aint_t refc;
 
     erts_smp_rwmtx_rwlock(&erts_dist_table_rwmtx);
@@ -316,26 +436,39 @@ static void try_delete_dist_entry(void *vdep)
      *
      * If refc > 0, the entry is in use. Keep the entry.
      */
-    refc = erts_smp_refc_dectest(&dep->refc, -1);
+    refc = de_refc_dec_read(dep, -1);
     if (refc == -1)
 	(void) hash_erase(&erts_dist_table, (void *) dep);
     erts_smp_rwmtx_rwunlock(&erts_dist_table_rwmtx);
 
-    if (refc == 0)
-	erts_schedule_delete_dist_entry(dep);
+    if (refc == 0) {
+        if (node_tab_delete_delay == 0)
+            prepare_try_delete_dist_entry(vbin);
+        else if (node_tab_delete_delay > 0)
+            erts_start_timer_callback(node_tab_delete_delay,
+                                      prepare_try_delete_dist_entry,
+                                      vbin);
+    }
 }
 
-void erts_schedule_delete_dist_entry(DistEntry *dep)
+int erts_dist_entry_destructor(Binary *bin)
 {
-    ASSERT(dep != erts_this_dist_entry);
-    if (dep != erts_this_dist_entry) {
-	if (node_tab_delete_delay == 0)
-	    try_delete_dist_entry((void *) dep);
-	else if (node_tab_delete_delay > 0)
-	    erts_start_timer_callback(node_tab_delete_delay,
-				      try_delete_dist_entry,
-				      (void *) dep);
-    }
+    DistEntry *dep = ErtsBin2DistEntry(bin);
+    erts_aint_t refc;
+
+    refc = de_refc_read(dep, -1);
+
+    if (refc == -1)
+        return 1; /* Allow deallocation of structure... */
+
+    if (node_tab_delete_delay == 0)
+        prepare_try_delete_dist_entry((void *) bin);
+    else if (node_tab_delete_delay > 0)
+        erts_start_timer_callback(node_tab_delete_delay,
+                                  prepare_try_delete_dist_entry,
+                                  (void *) bin);
+
+    return 0;
 }
 
 Uint
@@ -729,19 +862,18 @@ void
 erts_set_this_node(Eterm sysname, Uint creation)
 {
     ERTS_SMP_LC_ASSERT(erts_thr_progress_is_blocking());
-    ASSERT(erts_smp_refc_read(&erts_this_dist_entry->refc, 2));
+    ASSERT(2 <= de_refc_read(erts_this_dist_entry, 2));
 
     if (erts_smp_refc_dectest(&erts_this_node->refc, 0) == 0)
         try_delete_node(erts_this_node);
 
-    if (erts_smp_refc_dectest(&erts_this_dist_entry->refc, 0) == 0)
-        try_delete_dist_entry(erts_this_dist_entry);
+    erts_deref_dist_entry(erts_this_dist_entry);
 
     erts_this_node = NULL; /* to make sure refc is bumped for this node */
     erts_this_node = erts_find_or_insert_node(sysname, creation);
     erts_this_dist_entry = erts_this_node->dist_entry;
 
-    erts_smp_refc_inc(&erts_this_dist_entry->refc, 2);
+    erts_ref_dist_entry(erts_this_dist_entry);
 
     erts_this_node_sysname = erts_this_node_sysname_BUFFER;
     erts_snprintf(erts_this_node_sysname, sizeof(erts_this_node_sysname_BUFFER),
@@ -808,9 +940,9 @@ void erts_init_node_tables(int dd_sec)
     ASSERT(erts_this_node->dist_entry != NULL);
     erts_this_dist_entry = erts_this_node->dist_entry;
     /* +1 for erts_this_dist_entry */
-    /* +1 for erts_this_node->dist_entry */
-    erts_smp_refc_init(&erts_this_dist_entry->refc, 2);
+    erts_ref_dist_entry(erts_this_dist_entry);
 
+    ASSERT(2 == de_refc_read(erts_this_dist_entry, 2));
 
     erts_this_node_sysname = erts_this_node_sysname_BUFFER;
     erts_snprintf(erts_this_node_sysname, sizeof(erts_this_node_sysname_BUFFER),
@@ -862,6 +994,7 @@ static Eterm AM_node_references;
 static Eterm AM_system;
 static Eterm AM_timer;
 static Eterm AM_delayed_delete_timer;
+static Eterm AM_thread_progress_delete_timer;
 
 static void setup_reference_table(void);
 static Eterm reference_table_term(Uint **hpp, ErlOffHeap *ohp, Uint *szp);
@@ -951,6 +1084,7 @@ erts_get_node_and_dist_references(struct process *proc)
 	INIT_AM(timer);
 	INIT_AM(system);
 	INIT_AM(delayed_delete_timer);
+        INIT_AM(thread_progress_delete_timer);
 	references_atoms_need_init = 0;
     }
 
@@ -1134,6 +1268,10 @@ insert_offheap2(ErlOffHeap *oh, void *arg)
     insert_offheap(oh, a->type, a->id);
 }
 
+#define ErtsIsDistEntryBinary(Bin)                                      \
+    (((Bin)->intern.flags & BIN_FLAG_MAGIC)                             \
+     && ERTS_MAGIC_BIN_DESTRUCTOR((Bin)) == erts_dist_entry_destructor)
+
 static void
 insert_offheap(ErlOffHeap *oh, int type, Eterm id)
 {
@@ -1144,7 +1282,10 @@ insert_offheap(ErlOffHeap *oh, int type, Eterm id)
     for (u.hdr = oh->first; u.hdr; u.hdr = u.hdr->next) {
 	switch (thing_subtag(u.hdr->thing_word)) {
 	case REF_SUBTAG:
-	    if(IsMatchProgBinary(u.mref->mb)) {
+            if (ErtsIsDistEntryBinary(u.mref->mb))
+                insert_dist_entry(ErtsBin2DistEntry(u.mref->mb),
+                                  type, id, 0);
+	    else if(IsMatchProgBinary(u.mref->mb)) {
 		InsertedBin *ib;
 		int insert_bin = 1;
 		for (ib = inserted_bins; ib; ib = ib->next)
@@ -1289,26 +1430,34 @@ insert_delayed_delete_node(void *state,
 			   ErtsMonotonicTime timeout_pos,
 			   void *vnp)
 {
-    DeclareTmpHeapNoproc(heap,3);
-    UseTmpHeapNoproc(3);
+    Eterm heap[3];
     insert_node((ErlNode *) vnp,
 		SYSTEM_REF,
 		TUPLE2(&heap[0], AM_system, AM_delayed_delete_timer));
-    UnUseTmpHeapNoproc(3);
+}
+
+static void
+insert_thr_prgr_delete_dist_entry(void *arg, ErtsThrPrgrVal thr_prgr, void *vbin)
+{
+    DistEntry *dep = ErtsBin2DistEntry(vbin);
+    Eterm heap[3];
+    insert_dist_entry(dep,
+		      SYSTEM_REF,
+		      TUPLE2(&heap[0], AM_system, AM_thread_progress_delete_timer),
+		      0);
 }
 
 static void
 insert_delayed_delete_dist_entry(void *state,
 				 ErtsMonotonicTime timeout_pos,
-				 void *vdep)
+				 void *vbin)
 {
-    DeclareTmpHeapNoproc(heap,3);
-    UseTmpHeapNoproc(3);
-    insert_dist_entry((DistEntry *) vdep,
+    DistEntry *dep = ErtsBin2DistEntry(vbin);
+    Eterm heap[3];
+    insert_dist_entry(dep,
 		      SYSTEM_REF,
 		      TUPLE2(&heap[0], AM_system, AM_delayed_delete_timer),
 		      0);
-    UnUseTmpHeapNoproc(3);
 }
 
 static void
@@ -1342,9 +1491,12 @@ setup_reference_table(void)
     erts_debug_callback_timer_foreach(try_delete_node,
 				      insert_delayed_delete_node,
 				      NULL);
-    erts_debug_callback_timer_foreach(try_delete_dist_entry,
+    erts_debug_callback_timer_foreach(prepare_try_delete_dist_entry,
 				      insert_delayed_delete_dist_entry,
 				      NULL);
+    erts_debug_later_op_foreach(try_delete_dist_entry,
+                                insert_thr_prgr_delete_dist_entry,
+                                NULL);
 
     UseTmpHeapNoproc(3);
     insert_node(erts_this_node,
@@ -1719,7 +1871,7 @@ reference_table_term(Uint **hpp, ErlOffHeap *ohp, Uint *szp)
 
 	/* DistList = [{Dist, Refc, ReferenceIdList}] */
 	tup = MK_3TUP(referred_dists[i].dist->sysname,
-		      MK_UINT(erts_smp_refc_read(&referred_dists[i].dist->refc, 0)),
+		      MK_UINT(de_refc_read(referred_dists[i].dist, 0)),
 		      dril);
 	dl = MK_CONS(tup, dl);
     }