3 files changed, 22 insertions, 28 deletions

diff --git a/erts/emulator/beam/erl_db_hash.c b/erts/emulator/beam/erl_db_hash.c
index 74979f984a..074ac6d64e 100644
--- a/erts/emulator/beam/erl_db_hash.c
+++ b/erts/emulator/beam/erl_db_hash.c
@@ -95,7 +95,8 @@
 /* 
  * The following symbols can be manipulated to "tune" the linear hash array 
  */
-#define CHAIN_LEN 6                 /* Medium bucket chain len      */
+#define GROW_LIMIT(NACTIVE) ((NACTIVE)*2)
+#define SHRINK_LIMIT(NACTIVE) ((NACTIVE) / 2)
 
 /* Number of slots per segment */
 #define SEGSZ_EXP  8
@@ -463,7 +464,7 @@ db_finalize_dbterm_hash(int cret, DbUpdateHandle* handle);
 static ERTS_INLINE void try_shrink(DbTableHash* tb)
 {
     int nactive = NACTIVE(tb);
-    if (nactive > SEGSZ && NITEMS(tb) < (nactive * CHAIN_LEN)
+    if (nactive > SEGSZ && NITEMS(tb) < SHRINK_LIMIT(nactive)
 	&& !IS_FIXED(tb)) {
 	shrink(tb, nactive);
     }
@@ -670,8 +671,8 @@ int db_create_hash(Process *p, DbTable *tbl)
     tb->nsegs = NSEG_1;
     tb->nslots = SEGSZ;
 
-    erts_smp_atomic_init_nob(&tb->is_resizing, 0);
 #ifdef ERTS_SMP
+    erts_smp_atomic_init_nob(&tb->is_resizing, 0);
     if (tb->common.type & DB_FINE_LOCKED) {
 	erts_smp_rwmtx_opt_t rwmtx_opt = ERTS_SMP_RWMTX_OPT_DEFAULT_INITER;
 	int i;
@@ -862,7 +863,7 @@ Lnew:
     WUNLOCK_HASH(lck);
     {
 	int nactive = NACTIVE(tb);       
-	if (nitems > nactive * (CHAIN_LEN+1) && !IS_FIXED(tb)) {
+	if (nitems > GROW_LIMIT(nactive) && !IS_FIXED(tb)) {
 	    grow(tb, nactive);
 	}
     }
@@ -2250,12 +2251,12 @@ static int db_free_table_continue_hash(DbTable *tbl)
 
     done /= 2;
     while(tb->nslots != 0) {
-	free_seg(tb, 1);
+	done += 1 + SEGSZ/64 + free_seg(tb, 1);
 
 	/*
 	 * If we have done enough work, get out here.
 	 */
-	if (++done >= (DELETE_RECORD_LIMIT / CHAIN_LEN / SEGSZ)) {
+	if (done >= DELETE_RECORD_LIMIT) {
 	    return 0;	/* Not done */
 	}
     }
@@ -2604,23 +2605,22 @@ static Eterm build_term_list(Process* p, HashDbTerm* ptr1, HashDbTerm* ptr2,
 static ERTS_INLINE int
 begin_resizing(DbTableHash* tb)
 {
+#ifdef ERTS_SMP
     if (DB_USING_FINE_LOCKING(tb))
-	return !erts_smp_atomic_xchg_acqb(&tb->is_resizing, 1);
-    else {
-	if (erts_smp_atomic_read_nob(&tb->is_resizing))
-	    return 0;
-	erts_smp_atomic_set_nob(&tb->is_resizing, 1);
-	return 1;
-    }
+	return !erts_atomic_xchg_acqb(&tb->is_resizing, 1);
+    else
+        ERTS_LC_ASSERT(erts_lc_rwmtx_is_rwlocked(&tb->common.rwlock));
+#endif
+    return 1;
 }
 
 static ERTS_INLINE void
 done_resizing(DbTableHash* tb)
 {
+#ifdef ERTS_SMP
     if (DB_USING_FINE_LOCKING(tb))
-	erts_smp_atomic_set_relb(&tb->is_resizing, 0);
-    else
-	erts_smp_atomic_set_nob(&tb->is_resizing, 0);
+	erts_atomic_set_relb(&tb->is_resizing, 0);
+#endif
 }
 
 /* Grow table with one new bucket.
@@ -2871,7 +2871,7 @@ db_lookup_dbterm_hash(Process *p, DbTable *tbl, Eterm key, Eterm obj,
                 int nitems = erts_smp_atomic_inc_read_nob(&tb->common.nitems);
                 int nactive = NACTIVE(tb);
 
-                if (nitems > nactive * (CHAIN_LEN + 1) && !IS_FIXED(tb)) {
+                if (nitems > GROW_LIMIT(nactive) && !IS_FIXED(tb)) {
                     grow(tb, nactive);
                 }
             }
diff --git a/erts/emulator/beam/erl_db_hash.h b/erts/emulator/beam/erl_db_hash.h
index e654363cd5..081ff8fafc 100644
--- a/erts/emulator/beam/erl_db_hash.h
+++ b/erts/emulator/beam/erl_db_hash.h
@@ -60,8 +60,8 @@ typedef struct db_table_hash {
     /* List of slots where elements have been deleted while table was fixed */
     erts_smp_atomic_t fixdel;  /* (FixedDeletion*) */	
     erts_smp_atomic_t nactive; /* Number of "active" slots */
-    erts_smp_atomic_t is_resizing; /* grow/shrink in progress */
 #ifdef ERTS_SMP
+    erts_smp_atomic_t is_resizing; /* grow/shrink in progress */
     DbTableHashFineLocks* locks;
 #endif
 #ifdef VALGRIND
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index f1c35cd5a5..4fd82bad10 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -803,19 +803,13 @@ ERL_NIF_TERM enif_make_copy(ErlNifEnv* dst_env, ERL_NIF_TERM src_term)
 {
     Uint sz;
     Eterm* hp;
-#ifdef SHCOPY
-    erts_shcopy_t info;
-    INITIALIZE_SHCOPY(info);
-    sz = copy_shared_calculate(src_term, &info);
-    hp = alloc_heap(dst_env, sz);
-    src_term = copy_shared_perform(src_term, sz, &info, &hp, &MSO(dst_env->proc));
-    DESTROY_SHCOPY(info);
-    return src_term;
-#else
+    /*
+     * No preserved sharing allowed as long as literals are also preserved.
+     * Process independent environment can not be reached by purge.
+     */
     sz = size_object(src_term);
     hp = alloc_heap(dst_env, sz);
     return copy_struct(src_term, sz, &hp, &MSO(dst_env->proc));
-#endif
 }