Merge branch 'bjorn/erts/persistent_terms/OTP-14669' into maint

* bjorn/erts/persistent_terms/OTP-14669:
  Implement a tab for persistent terms in crashdump viewer
  Add tests of persistent terms for crashdump_viewer
  Add a persistent term storage
  Refactor releasing of literals
  Extend the sharing-preserving routines to optionally copy literals

34 files changed, 2291 insertions, 62 deletions

diff --git a/erts/doc/src/Makefile b/erts/doc/src/Makefile
index 21aa3db864..fccdd744f3 100644
--- a/erts/doc/src/Makefile
+++ b/erts/doc/src/Makefile
@@ -52,6 +52,7 @@ XML_REF3_EFILES = \
 	erlang.xml \
 	erl_tracer.xml \
 	init.xml \
+	persistent_term.xml \
 	zlib.xml
 
 XML_REF3_FILES = \
@@ -63,6 +64,7 @@ XML_REF3_FILES = \
 	erlang.xml \
 	erts_alloc.xml  \
 	init.xml \
+	persistent_term.xml \
 	zlib.xml
 
 XML_PART_FILES = \
diff --git a/erts/doc/src/persistent_term.xml b/erts/doc/src/persistent_term.xml
new file mode 100644
index 0000000000..d2a138d65f
--- /dev/null
+++ b/erts/doc/src/persistent_term.xml
@@ -0,0 +1,290 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE erlref SYSTEM "erlref.dtd">
+
+<erlref>
+  <header>
+    <copyright>
+      <year>2018</year><year>2018</year>
+      <holder>Ericsson AB. All Rights Reserved.</holder>
+    </copyright>
+    <legalnotice>
+      Licensed under the Apache License, Version 2.0 (the "License");
+      you may not use this file except in compliance with the License.
+      You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+      See the License for the specific language governing permissions and
+      limitations under the License.
+
+    </legalnotice>
+
+    <title>persistent_term</title>
+    <prepared></prepared>
+    <docno></docno>
+    <date></date>
+    <rev></rev>
+    <file>persistent_term.xml</file>
+  </header>
+  <module>persistent_term</module>
+  <modulesummary>Persistent terms.</modulesummary>
+  <description>
+    <p>This module is similar to <seealso
+    marker="stdlib:ets"><c>ets</c></seealso> in that it provides a
+    storage for Erlang terms that can be accessed in constant time,
+    but with the difference that <c>persistent_term</c> has been
+    highly optimized for reading terms at the expense of writing and
+    updating terms. When a persistent term is updated or deleted, a
+    global garbage collection pass is run to scan all processes for
+    the deleted term, and to copy it into each process that still uses
+    it. Therefore, <c>persistent_term</c> is suitable for storing
+    Erlang terms that are frequently accessed but never or
+    infrequently updated.</p>
+
+    <warning><p>Persistent terms is an advanced feature and is not a
+    general replacement for ETS tables. Before using persistent terms,
+    make sure to fully understand the consequence to system
+    performance when updating or deleting persistent terms.</p></warning>
+
+    <p>Term lookup (using <seealso
+    marker="#get/1"><c>get/1</c></seealso>), is done in constant time
+    and without taking any locks, and the term is <strong>not</strong>
+    copied to the heap (as is the case with terms stored in ETS
+    tables).</p>
+
+    <p>Storing or updating a term (using <seealso
+    marker="#put/2"><c>put/2</c></seealso>) is proportional to the
+    number of already created persistent terms because the hash table
+    holding the keys will be copied. In addition, the term itself will
+    be copied.</p>
+
+    <p>When a (complex) term is deleted (using <seealso
+    marker="#erase/1"><c>erase/1</c></seealso>) or replaced by another
+    (using <seealso marker="#put/2"><c>put/2</c></seealso>), a global
+    garbage collection is initiated. It works like this:</p>
+
+    <list>
+      <item><p>All processes in the system will be scheduled to run a
+      scan of their heaps for the term that has been deleted.  While
+      such scan is relatively light-weight, if there are many
+      processes, the system can become less responsive until all
+      process have scanned theirs heaps.</p></item>
+
+      <item><p>If the deleted term (or any part of it) is still used
+      by a process, that process will do a major (fullsweep) garbage
+      collection and copy the term into the process. However, at most
+      two processes at a time will be scheduled to do that kind of
+      garbage collection.</p></item>
+    </list>
+
+    <p>Deletion of atoms and other terms that fit in one machine word
+    is specially optimized to avoid doing a global GC. It is still not
+    recommended to update persistent terms with such values too
+    frequently because the hash table holding the keys is copied every
+    time a persistent term is updated.</p>
+
+    <p>Some examples are suitable uses for persistent terms are:</p>
+
+    <list>
+      <item><p>Storing of configuration data that must be easily
+      accessible by all processes.</p></item>
+
+      <item><p>Storing of references for NIF resources.</p></item>
+
+      <item><p>Storing of references for efficient counters.</p></item>
+
+      <item><p>Storing an atom to indicate a logging level or whether debugging
+      is turned on.</p></item>
+    </list>
+
+  </description>
+
+  <section>
+    <title>Storing Huge Persistent Terms</title>
+    <p>The current implementation of persistent terms uses the literal
+    <seealso marker="erts_alloc">allocator</seealso> also used for
+    literals (constant terms) in BEAM code.  By default, 1 GB of
+    virtual address space is reserved for literals in BEAM code and
+    persistent terms. The amount of virtual address space reserved for
+    literals can be changed by using the <seealso
+    marker="erts_alloc#MIscs"><c>+MIscs option</c></seealso> when
+    starting the emulator.</p>
+
+    <p>Here is an example how the reserved virtual address space for literals
+    can be raised to 2 GB (2048 MB):</p>
+
+    <pre>
+    erl +MIscs 2048</pre>
+  </section>
+
+  <section>
+    <title>Warning For Many Persistent Terms</title>
+    <p>The runtime system will send a warning report to the
+    error logger if more than 20000 persistent terms have been
+    created. It will look like this:</p>
+
+<pre>
+More than 20000 persistent terms have been created.
+It is recommended to avoid creating an excessive number of
+persistent terms, as creation and deletion of persistent terms
+will be slower as the number of persistent terms increases.</pre>
+  </section>
+
+  <section>
+    <title>Best Practices for Using Persistent Terms</title>
+
+    <p>It is recommended to use keys like <c>?MODULE</c> or
+    <c>{?MODULE,SubKey}</c> to avoid name collisions.</p>
+
+    <p>Prefer creating a few large persistent terms to creating many
+    small persistent terms. The execution time for storing a
+    persistent term is proportional to the number of already existing
+    terms.</p>
+
+    <p>Updating a persistent term with the same value as it already
+    has is specially optimized to do nothing quickly; thus, there is
+    no need compare the old and new values and avoid calling
+    <seealso marker="#put/2"><c>put/2</c></seealso> if the values
+    are equal.</p>
+
+    <p>When atoms or other terms that fit in one machine word are
+    deleted, no global GC is needed. Therefore, persistent terms that
+    have atoms as their values can be updated more frequently, but
+    note that updating such persistent terms is still much more
+    expensive than reading them.</p>
+
+    <p>Updating or deleting a persistent term will trigger a global GC
+    if the term does not fit in one machine word. Processes will be
+    scheduled as usual, but all processes will be made runnable at
+    once, which will make the system less responsive until all process
+    have run and scanned their heaps for the deleted terms. One way to
+    minimize the effects on responsiveness could be to minimize the
+    number of processes on the node before updating or deleting a
+    persistent term. It would also be wise to avoid updating terms
+    when the system is at peak load.</p>
+
+    <p>Avoid storing a retrieved persistent term in a process if that
+    persistent term could be deleted or updated in the future. If a
+    process holds a reference to a persistent term when the term is
+    deleted, the process will be garbage collected and the term copied
+    to process.</p>
+
+    <p>Avoid updating or deleting more than one persistent term at a
+    time.  Each deleted term will trigger its own global GC. That
+    means that deleting N terms will make the system less responsive N
+    times longer than deleting a single persistent term. Therefore,
+    terms that are to be updated at the same time should be collected
+    into a larger term, for example, a map or a tuple.</p>
+  </section>
+
+  <section>
+    <title>Example</title>
+
+    <p>The following example shows how lock contention for ETS tables
+    can be minimized by having one ETS table for each scheduler. The
+    table identifiers for the ETS tables are stored as a single
+    persistent term:</p>
+
+<pre>
+    %% There is one ETS table for each scheduler.
+    Sid = erlang:system_info(scheduler_id),
+    Tid = element(Sid, persistent_term:get(?MODULE)),
+    ets:update_counter(Tid, Key, 1).</pre>
+
+  </section>
+
+  <datatypes>
+    <datatype>
+      <name name="key"/>
+      <desc>
+        <p>Any Erlang term.</p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="value"/>
+      <desc>
+        <p>Any Erlang term.</p>
+      </desc>
+    </datatype>
+  </datatypes>
+
+  <funcs>
+    <func>
+      <name name="erase" arity="1"/>
+      <fsummary>Erase the name for a persistent term.</fsummary>
+      <desc>
+        <p>Erase the name for the persistent term with key
+	<c><anno>Key</anno></c>. The return value will be <c>true</c>
+	if there was a persistent term with the key
+	<c><anno>Key</anno></c>, and <c>false</c> if there was no
+	persistent term associated with the key.</p>
+	<p>If there existed a previous persistent term associated with
+	key <c><anno>Key</anno></c>, a global GC has been initiated
+	when <c>erase/1</c> returns. See <seealso
+	marker="#description">Description</seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="get" arity="0"/>
+      <fsummary>Get all persistent terms.</fsummary>
+      <desc>
+        <p>Retrieve the keys and values for all persistent terms.
+	The keys will be copied to the heap for the process calling
+	<c>get/0</c>, but the values will not.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="get" arity="1"/>
+      <fsummary>Get the value for a persistent term.</fsummary>
+      <desc>
+        <p>Retrieve the value for the persistent term associated with
+        the key <c><anno>Key</anno></c>. The lookup will be made in
+	constant time and the value will not be copied to the heap
+	of the calling process.</p>
+	<p>This function fails with a <c>badarg</c> exception if no
+	term has been stored with the key
+	<c><anno>Key</anno></c>.</p>
+	<p>If the calling process holds on to the value of the
+	persistent term and the persistent term is deleted in the future,
+	the term will be copied to the process.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="info" arity="0"/>
+      <fsummary>Get information about persistent terms.</fsummary>
+      <desc>
+        <p>Return information about persistent terms in a map. The map
+	has the following keys:</p>
+	<taglist>
+	  <tag><c>count</c></tag>
+	  <item><p>The number of persistent terms.</p></item>
+	  <tag><c>memory</c></tag>
+	  <item><p>The total amount of memory (measured in bytes)
+	  used by all persistent terms.</p></item>
+	</taglist>
+      </desc>
+    </func>
+
+    <func>
+      <name name="put" arity="2"/>
+      <fsummary>Store a term.</fsummary>
+      <desc>
+        <p>Store the value <c><anno>Value</anno></c> as a persistent term and
+	associate it with the key <c><anno>Key</anno></c>.</p>
+	<p>If the value <c><anno>Value</anno></c> is equal to the value
+	previously stored for the key, <c>put/2</c> will do nothing and return
+	quickly.</p>
+	<p>If there existed a previous persistent term associated with
+	key <c><anno>Key</anno></c>, a global GC has been initiated
+	when <c>put/2</c> returns. See <seealso
+	marker="#description">Description</seealso>.</p>
+      </desc>
+    </func>
+  </funcs>
+</erlref>
diff --git a/erts/doc/src/ref_man.xml b/erts/doc/src/ref_man.xml
index 0617463a7b..ff64aa86b8 100644
--- a/erts/doc/src/ref_man.xml
+++ b/erts/doc/src/ref_man.xml
@@ -34,6 +34,7 @@
   <xi:include href="erl_prim_loader.xml"/>
   <xi:include href="erlang.xml"/>
   <xi:include href="init.xml"/>
+  <xi:include href="persistent_term.xml"/>
   <xi:include href="zlib.xml"/>
   <xi:include href="epmd.xml"/>
   <xi:include href="erl.xml"/>
diff --git a/erts/doc/src/specs.xml b/erts/doc/src/specs.xml
index ed6be650e5..1ab6cdc19e 100644
--- a/erts/doc/src/specs.xml
+++ b/erts/doc/src/specs.xml
@@ -4,5 +4,6 @@
   <xi:include href="../specs/specs_erlang.xml"/>
   <xi:include href="../specs/specs_erl_tracer.xml"/>
   <xi:include href="../specs/specs_init.xml"/>
+  <xi:include href="../specs/specs_persistent_term.xml"/>
   <xi:include href="../specs/specs_zlib.xml"/>
 </specs>
diff --git a/erts/emulator/Makefile.in b/erts/emulator/Makefile.in
index 054692819e..d5ceb4b00b 100644
--- a/erts/emulator/Makefile.in
+++ b/erts/emulator/Makefile.in
@@ -633,21 +633,22 @@ GENERATE += $(TTF_DIR)/driver_tab.c
 # This list must be consistent with PRE_LOADED_MODULES in
 # erts/preloaded/src/Makefile.
 
-PRELOAD_BEAM =		$(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erts_code_purger.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/init.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/prim_buffer.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/prim_eval.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/prim_inet.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/prim_file.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/zlib.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/prim_zip.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erl_prim_loader.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erlang.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erts_internal.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erl_tracer.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erts_literal_area_collector.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erts_dirty_process_signal_handler.beam
+PRELOAD_BEAM =	$(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/erts_code_purger.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/init.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/prim_buffer.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/prim_eval.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/prim_inet.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/prim_file.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/zlib.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/prim_zip.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/erl_prim_loader.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/erlang.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/erts_internal.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/erl_tracer.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/erts_literal_area_collector.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/erts_dirty_process_signal_handler.beam \
+		$(ERL_TOP)/erts/preloaded/ebin/persistent_term.beam
 
 ifeq ($(TARGET),win32)
 # On windows the preloaded objects are in a resource object.
@@ -839,6 +840,7 @@ RUN_OBJS += \
 	$(OBJDIR)/erl_bif_ddll.o  	$(OBJDIR)/erl_bif_guard.o \
 	$(OBJDIR)/erl_bif_info.o	$(OBJDIR)/erl_bif_op.o \
 	$(OBJDIR)/erl_bif_os.o		$(OBJDIR)/erl_bif_lists.o \
+	$(OBJDIR)/erl_bif_persistent.o \
 	$(OBJDIR)/erl_bif_trace.o	$(OBJDIR)/erl_bif_unique.o \
 	$(OBJDIR)/erl_bif_wrap.o	$(OBJDIR)/erl_nfunc_sched.o \
 	$(OBJDIR)/erl_guard_bifs.o 	$(OBJDIR)/erl_dirty_bif_wrap.o \
diff --git a/erts/emulator/beam/atom.names b/erts/emulator/beam/atom.names
index 45b7540aeb..82bb620d62 100644
--- a/erts/emulator/beam/atom.names
+++ b/erts/emulator/beam/atom.names
@@ -182,6 +182,7 @@ atom control
 atom copy
 atom copy_literals
 atom counters
+atom count
 atom cpu
 atom cpu_timestamp
 atom cr
@@ -287,6 +288,7 @@ atom gc_minor_end
 atom gc_minor_start
 atom Ge='>='
 atom generational
+atom get_all_trap
 atom get_seq_token
 atom get_tcw
 atom gather_gc_info_result
@@ -325,6 +327,7 @@ atom index
 atom infinity
 atom info
 atom info_msg
+atom info_trap
 atom init
 atom initial_call
 atom input
diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index d221e6aea6..bb1b2e5b27 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -1752,29 +1752,7 @@ BIF_RETTYPE erts_internal_purge_module_2(BIF_ALIST_2)
 	finalize_purge_operation(BIF_P, ret == am_true);
 
 	if (literals) {
-	    ErtsLiteralAreaRef *ref;
-            ErtsMessage *mp;
-	    ref = erts_alloc(ERTS_ALC_T_LITERAL_REF,
-			     sizeof(ErtsLiteralAreaRef));
-	    ref->literal_area = literals;
-	    ref->next = NULL;
-	    erts_mtx_lock(&release_literal_areas.mtx);
-	    if (release_literal_areas.last) {
-		release_literal_areas.last->next = ref;
-		release_literal_areas.last = ref;
-	    }
-	    else {
-		release_literal_areas.first = ref;
-		release_literal_areas.last = ref;
-	    }
-	    erts_mtx_unlock(&release_literal_areas.mtx);
-            mp = erts_alloc_message(0, NULL);
-            ERL_MESSAGE_TOKEN(mp) = am_undefined;
-	    erts_queue_proc_message(BIF_P,
-                               erts_literal_area_collector,
-			       0,
-			       mp,
-			       am_copy_literals);
+            erts_queue_release_literals(BIF_P, literals);
 	}
 
 	return ret;
@@ -1786,6 +1764,41 @@ BIF_RETTYPE erts_internal_purge_module_2(BIF_ALIST_2)
     }
 }
 
+void
+erts_queue_release_literals(Process* c_p, ErtsLiteralArea* literals)
+{
+    ErtsLiteralAreaRef *ref;
+    ErtsMessage *mp;
+    ref = erts_alloc(ERTS_ALC_T_LITERAL_REF,
+                     sizeof(ErtsLiteralAreaRef));
+    ref->literal_area = literals;
+    ref->next = NULL;
+    erts_mtx_lock(&release_literal_areas.mtx);
+    if (release_literal_areas.last) {
+        release_literal_areas.last->next = ref;
+        release_literal_areas.last = ref;
+    } else {
+        release_literal_areas.first = ref;
+        release_literal_areas.last = ref;
+    }
+    erts_mtx_unlock(&release_literal_areas.mtx);
+    mp = erts_alloc_message(0, NULL);
+    ERL_MESSAGE_TOKEN(mp) = am_undefined;
+    if (c_p == NULL) {
+        erts_queue_message(erts_literal_area_collector,
+                           0,
+                           mp,
+                           am_copy_literals,
+                           am_system);
+    } else {
+        erts_queue_proc_message(c_p,
+                                erts_literal_area_collector,
+                                0,
+                                mp,
+                                am_copy_literals);
+    }
+}
+
 /*
  * Move code from current to old and null all export entries for the module
  */
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 7548924178..f1f34ae323 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -40,6 +40,7 @@
 # Note: Guards BIFs usually require special support in the compiler.
 #
 
+
 gcbif erlang:abs/1
 bif erlang:adler32/1
 bif erlang:adler32/2
@@ -698,3 +699,14 @@ ubif erlang:map_get/2
 ubif erlang:is_map_key/2
 bif ets:internal_delete_all/2
 bif ets:internal_select_delete/2
+
+#
+# New in 21.2
+#
+
+bif persistent_term:put/2
+bif persistent_term:get/1
+bif persistent_term:get/0
+bif persistent_term:erase/1
+bif persistent_term:info/0
+bif erts_internal:erase_persistent_terms/0
diff --git a/erts/emulator/beam/copy.c b/erts/emulator/beam/copy.c
index e7bfd04b73..e7bd046e18 100644
--- a/erts/emulator/beam/copy.c
+++ b/erts/emulator/beam/copy.c
@@ -1074,6 +1074,7 @@ Uint copy_shared_calculate(Eterm obj, erts_shcopy_t *info)
     Eterm* ptr;
     Eterm *lit_purge_ptr = info->lit_purge_ptr;
     Uint lit_purge_sz = info->lit_purge_sz;
+    int copy_literals = info->copy_literals;
 #ifdef DEBUG
     Eterm mypid = erts_get_current_pid();
 #endif
@@ -1119,7 +1120,7 @@ Uint copy_shared_calculate(Eterm obj, erts_shcopy_t *info)
 	    /* off heap list pointers are copied verbatim */
 	    if (erts_is_literal(obj,ptr)) {
 		VERBOSE(DEBUG_SHCOPY, ("[pid=%T] bypassed copying %p is %T\n", mypid, ptr, obj));
-                if (in_literal_purge_area(ptr))
+                if (copy_literals || in_literal_purge_area(ptr))
                     info->literal_size += size_object(obj);
 		goto pop_next;
 	    }
@@ -1170,7 +1171,7 @@ Uint copy_shared_calculate(Eterm obj, erts_shcopy_t *info)
 	    /* off heap pointers to boxes are copied verbatim */
 	    if (erts_is_literal(obj,ptr)) {
 		VERBOSE(DEBUG_SHCOPY, ("[pid=%T] bypassed copying %p is %T\n", mypid, ptr, obj));
-                if (in_literal_purge_area(ptr))
+                if (copy_literals || in_literal_purge_area(ptr))
                     info->literal_size += size_object(obj);
 		goto pop_next;
 	    }
@@ -1338,6 +1339,7 @@ Uint copy_shared_perform(Eterm obj, Uint size, erts_shcopy_t *info,
     unsigned remaining;
     Eterm *lit_purge_ptr = info->lit_purge_ptr;
     Uint lit_purge_sz = info->lit_purge_sz;
+    int copy_literals = info->copy_literals;
 #ifdef DEBUG
     Eterm mypid = erts_get_current_pid();
     Eterm saved_obj = obj;
@@ -1387,7 +1389,7 @@ Uint copy_shared_perform(Eterm obj, Uint size, erts_shcopy_t *info,
 	    ptr = list_val(obj);
 	    /* off heap list pointers are copied verbatim */
 	    if (erts_is_literal(obj,ptr)) {
-                if (!in_literal_purge_area(ptr)) {
+                if (!(copy_literals || in_literal_purge_area(ptr))) {
                     *resp = obj;
                 } else {
                     Uint bsz = 0;
@@ -1455,7 +1457,7 @@ Uint copy_shared_perform(Eterm obj, Uint size, erts_shcopy_t *info,
 	    ptr = boxed_val(obj);
 	    /* off heap pointers to boxes are copied verbatim */
 	    if (erts_is_literal(obj,ptr)) {
-                if (!in_literal_purge_area(ptr)) {
+                if (!(copy_literals || in_literal_purge_area(ptr))) {
                     *resp = obj;
                 } else {
                     Uint bsz = 0;
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index 98ba0e5f07..3fc036a13c 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -278,6 +278,9 @@ type    LIST_TRAP       SHORT_LIVED     PROCESSES       list_bif_trap_state
 
 type	ENVIRONMENT	SYSTEM		SYSTEM		environment
 
+type	PERSISTENT_TERM	LONG_LIVED	CODE		persisten_term
+type	PERSISTENT_LOCK_Q SHORT_LIVED	SYSTEM		persistent_lock_q
+
 #
 # Types used for special emulators
 #
diff --git a/erts/emulator/beam/erl_bif_persistent.c b/erts/emulator/beam/erl_bif_persistent.c
new file mode 100644
index 0000000000..9dca768a18
--- /dev/null
+++ b/erts/emulator/beam/erl_bif_persistent.c
@@ -0,0 +1,983 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2018. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * %CopyrightEnd%
+ */
+
+/*
+ * Purpose: Implement persistent term storage.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include "sys.h"
+#include "erl_vm.h"
+#include "global.h"
+#include "erl_process.h"
+#include "error.h"
+#include "erl_driver.h"
+#include "bif.h"
+#include "erl_map.h"
+#include "erl_binary.h"
+
+/*
+ * The limit for the number of persistent terms before
+ * a warning is issued.
+ */
+
+#define WARNING_LIMIT 20000
+#define XSTR(s) STR(s)
+#define STR(s) #s
+
+/*
+ * Parameters for the hash table.
+ */
+#define INITIAL_SIZE 8
+#define LOAD_FACTOR ((Uint)50)
+#define MUST_GROW(t) (((Uint)100) * t->num_entries >= LOAD_FACTOR * t->allocated)
+#define MUST_SHRINK(t) (((Uint)200) * t->num_entries <= LOAD_FACTOR * t->allocated && \
+                        t->allocated > INITIAL_SIZE)
+
+typedef struct hash_table {
+    Uint allocated;
+    Uint num_entries;
+    Uint mask;
+    Uint first_to_delete;
+    Uint num_to_delete;
+    erts_atomic_t refc;
+    struct hash_table* delete_next;
+    ErtsThrPrgrLaterOp thr_prog_op;
+    Eterm term[1];
+} HashTable;
+
+typedef struct trap_data {
+    HashTable* table;
+    Uint idx;
+    Uint remaining;
+    Uint memory;    /* Used by info/0 to count used memory */
+} TrapData;
+
+/*
+ * Declarations of local functions.
+ */
+
+static HashTable* create_initial_table(void);
+static Uint lookup(HashTable* hash_table, Eterm key);
+static HashTable* copy_table(HashTable* old_table, Uint new_size, int rehash);
+static HashTable* tmp_table_copy(HashTable* old_table);
+static int try_seize_update_permission(Process* c_p);
+static void release_update_permission(int release_updater);
+static void table_updater(void* table);
+static void table_deleter(void* hash_table);
+static void dec_table_refc(Process* c_p, HashTable* old_table);
+static void delete_table(Process* c_p, HashTable* table);
+static void mark_for_deletion(HashTable* hash_table, Uint entry_index);
+static ErtsLiteralArea* term_to_area(Eterm tuple);
+static void suspend_updater(Process* c_p);
+static Eterm do_get_all(Process* c_p, TrapData* trap_data, Eterm res);
+static Eterm do_info(Process* c_p, TrapData* trap_data);
+static void append_to_delete_queue(HashTable* table);
+static HashTable* next_to_delete(void);
+static Eterm alloc_trap_data(Process* c_p);
+static int cleanup_trap_data(Binary *bp);
+
+/*
+ * Traps
+ */
+
+static Export persistent_term_get_all_export;
+static BIF_RETTYPE persistent_term_get_all_trap(BIF_ALIST_2);
+static Export persistent_term_info_export;
+static BIF_RETTYPE persistent_term_info_trap(BIF_ALIST_1);
+
+/*
+ * Pointer to the current hash table.
+ */
+
+static erts_atomic_t the_hash_table;
+
+/*
+ * Queue of processes waiting to update the hash table.
+ */
+
+struct update_queue_item {
+    Process *p;
+    struct update_queue_item* next;
+};
+
+static erts_mtx_t update_table_permission_mtx;
+static struct update_queue_item* update_queue = NULL;
+static Process* updater_process = NULL;
+
+/* Protected by update_table_permission_mtx */
+static ErtsThrPrgrLaterOp thr_prog_op;
+static int issued_warning = 0;
+
+/*
+ * Queue of hash tables to be deleted.
+ */
+
+static erts_mtx_t delete_queue_mtx;
+static HashTable* delete_queue_head = NULL;
+static HashTable** delete_queue_tail = &delete_queue_head;
+
+/*
+ * The following variables are only used during crash dumping. They
+ * are intialized by erts_init_persistent_dumping().
+ */
+
+ErtsLiteralArea** erts_persistent_areas;
+Uint erts_num_persistent_areas;
+
+void erts_init_bif_persistent_term(void)
+{
+    HashTable* hash_table;
+
+    /*
+     * Initialize the mutex protecting updates.
+     */
+
+    erts_mtx_init(&update_table_permission_mtx,
+                  "update_persistent_term_permission",
+                  NIL,
+                  ERTS_LOCK_FLAGS_PROPERTY_STATIC |
+                  ERTS_LOCK_FLAGS_CATEGORY_GENERIC);
+
+    /*
+     * Initialize delete queue.
+     */
+
+    erts_mtx_init(&delete_queue_mtx,
+                  "persistent_term_delete_permission",
+                  NIL,
+                  ERTS_LOCK_FLAGS_PROPERTY_STATIC |
+                  ERTS_LOCK_FLAGS_CATEGORY_GENERIC);
+
+    /*
+     * Allocate a small initial hash table.
+     */
+
+    hash_table = create_initial_table();
+    erts_atomic_init_nob(&the_hash_table, (erts_aint_t)hash_table);
+
+    /*
+     * Initialize export entry for traps
+     */
+
+    erts_init_trap_export(&persistent_term_get_all_export,
+			  am_persistent_term, am_get_all_trap, 2,
+			  &persistent_term_get_all_trap);
+    erts_init_trap_export(&persistent_term_info_export,
+			  am_persistent_term, am_info_trap, 1,
+			  &persistent_term_info_trap);
+}
+
+BIF_RETTYPE persistent_term_put_2(BIF_ALIST_2)
+{
+    Eterm key;
+    Eterm term;
+    Eterm heap[3];
+    Eterm tuple;
+    HashTable* hash_table;
+    Uint term_size;
+    Uint lit_area_size;
+    ErlOffHeap code_off_heap;
+    ErtsLiteralArea* literal_area;
+    erts_shcopy_t info;
+    Eterm* ptr;
+    Uint entry_index;
+
+    if (!try_seize_update_permission(BIF_P)) {
+	ERTS_BIF_YIELD2(bif_export[BIF_persistent_term_put_2],
+                        BIF_P, BIF_ARG_1, BIF_ARG_2);
+    }
+
+    hash_table = (HashTable *) erts_atomic_read_nob(&the_hash_table);
+
+    key = BIF_ARG_1;
+    term = BIF_ARG_2;
+
+    entry_index = lookup(hash_table, key);
+
+    heap[0] = make_arityval(2);
+    heap[1] = key;
+    heap[2] = term;
+    tuple = make_tuple(heap);
+
+    if (is_nil(hash_table->term[entry_index])) {
+        Uint size = hash_table->allocated;
+        if (MUST_GROW(hash_table)) {
+            size *= 2;
+        }
+        hash_table = copy_table(hash_table, size, 0);
+        entry_index = lookup(hash_table, key);
+        hash_table->num_entries++;
+    } else {
+        Eterm tuple = hash_table->term[entry_index];
+        Eterm old_term;
+
+        ASSERT(is_tuple_arity(tuple, 2));
+        old_term = boxed_val(tuple)[2];
+        if (EQ(term, old_term)) {
+            /* Same value. No need to update anything. */
+            release_update_permission(0);
+            BIF_RET(am_ok);
+        } else {
+            /* Mark the old term for deletion. */
+            mark_for_deletion(hash_table, entry_index);
+            hash_table = copy_table(hash_table, hash_table->allocated, 0);
+        }
+    }
+
+    /*
+     * Preserve internal sharing in the term by using the
+     * sharing-preserving functions. However, literals must
+     * be copied in case the module holding them are unloaded.
+     */
+    INITIALIZE_SHCOPY(info);
+    info.copy_literals = 1;
+    term_size = copy_shared_calculate(tuple, &info);
+    ERTS_INIT_OFF_HEAP(&code_off_heap);
+    lit_area_size = ERTS_LITERAL_AREA_ALLOC_SIZE(term_size);
+    literal_area = erts_alloc(ERTS_ALC_T_LITERAL, lit_area_size);
+    ptr = &literal_area->start[0];
+    literal_area->end = ptr + term_size;
+    tuple = copy_shared_perform(tuple, term_size, &info, &ptr, &code_off_heap);
+    ASSERT(tuple_val(tuple) == literal_area->start);
+    literal_area->off_heap = code_off_heap.first;
+    DESTROY_SHCOPY(info);
+    erts_set_literal_tag(&tuple, literal_area->start, term_size);
+    hash_table->term[entry_index] = tuple;
+
+    erts_schedule_thr_prgr_later_op(table_updater, hash_table, &thr_prog_op);
+    suspend_updater(BIF_P);
+
+    /*
+     * Issue a warning once if the warning limit has been exceeded.
+     */
+
+    if (hash_table->num_entries > WARNING_LIMIT && issued_warning == 0) {
+        static char w[] =
+            "More than " XSTR(WARNING_LIMIT) " persistent terms "
+            "have been created.\n"
+            "It is recommended to avoid creating an excessive number of\n"
+            "persistent terms, as creation and deletion of persistent terms\n"
+            "will be slower as the number of persistent terms increases.\n";
+        issued_warning = 1;
+	erts_send_warning_to_logger_str(BIF_P->group_leader, w);
+    }
+
+    ERTS_BIF_YIELD_RETURN(BIF_P, am_ok);
+}
+
+BIF_RETTYPE persistent_term_get_0(BIF_ALIST_0)
+{
+    HashTable* hash_table = (HashTable *) erts_atomic_read_nob(&the_hash_table);
+    TrapData* trap_data;
+    Eterm res = NIL;
+    Eterm magic_ref;
+    Binary* mbp;
+
+    magic_ref = alloc_trap_data(BIF_P);
+    mbp = erts_magic_ref2bin(magic_ref);
+    trap_data = ERTS_MAGIC_BIN_DATA(mbp);
+    trap_data->table = hash_table;
+    trap_data->idx = 0;
+    trap_data->remaining = hash_table->num_entries;
+    res = do_get_all(BIF_P, trap_data, res);
+    if (trap_data->remaining == 0) {
+        BUMP_REDS(BIF_P, hash_table->num_entries);
+        trap_data->table = NULL; /* Prevent refc decrement */
+        BIF_RET(res);
+    } else {
+        /*
+         * Increment the ref counter to prevent an update operation (by put/2
+         * or erase/1) to delete this hash table.
+         */
+        erts_atomic_inc_nob(&hash_table->refc);
+        BUMP_ALL_REDS(BIF_P);
+        BIF_TRAP2(&persistent_term_get_all_export, BIF_P, magic_ref, res);
+    }
+}
+
+BIF_RETTYPE persistent_term_get_1(BIF_ALIST_1)
+{
+    Eterm key = BIF_ARG_1;
+    HashTable* hash_table = (HashTable *) erts_atomic_read_nob(&the_hash_table);
+    Uint entry_index;
+    Eterm term;
+
+    entry_index = lookup(hash_table, key);
+    term = hash_table->term[entry_index];
+    if (is_boxed(term)) {
+        ASSERT(is_tuple_arity(term, 2));
+        BIF_RET(tuple_val(term)[2]);
+    }
+    BIF_ERROR(BIF_P, BADARG);
+}
+
+BIF_RETTYPE persistent_term_erase_1(BIF_ALIST_1)
+{
+    Eterm key = BIF_ARG_1;
+    HashTable* old_table;
+    HashTable* new_table;
+    Uint entry_index;
+    Eterm old_term;
+
+    if (!try_seize_update_permission(BIF_P)) {
+	ERTS_BIF_YIELD1(bif_export[BIF_persistent_term_erase_1],
+                        BIF_P, BIF_ARG_1);
+    }
+
+    old_table = (HashTable *) erts_atomic_read_nob(&the_hash_table);
+    entry_index = lookup(old_table, key);
+    old_term = old_table->term[entry_index];
+    if (is_boxed(old_term)) {
+        Uint new_size;
+        HashTable* tmp_table;
+
+        /*
+         * Since we don't use any delete markers, we must rehash
+         * the table when deleting terms to ensure that all terms
+         * can still be reached if there are hash collisions.
+         * We can't rehash in place and it would not be safe to modify
+         * the old table yet, so we will first need a new
+         * temporary table copy of the same size as the old one.
+         */
+
+        ASSERT(is_tuple_arity(old_term, 2));
+        tmp_table = tmp_table_copy(old_table);
+
+        /*
+         * Delete the term from the temporary table. Then copy the
+         * temporary table to a new table, rehashing the entries
+         * while copying.
+         */
+
+        tmp_table->term[entry_index] = NIL;
+        tmp_table->num_entries--;
+        new_size = tmp_table->allocated;
+        if (MUST_SHRINK(tmp_table)) {
+            new_size /= 2;
+        }
+        new_table = copy_table(tmp_table, new_size, 1);
+        erts_free(ERTS_ALC_T_TMP, tmp_table);
+
+        mark_for_deletion(old_table, entry_index);
+        erts_schedule_thr_prgr_later_op(table_updater, new_table, &thr_prog_op);
+        suspend_updater(BIF_P);
+        ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
+    }
+
+    /*
+     * Key is not present. Nothing to do.
+     */
+
+    ASSERT(is_nil(old_term));
+    release_update_permission(0);
+    BIF_RET(am_false);
+}
+
+BIF_RETTYPE erts_internal_erase_persistent_terms_0(BIF_ALIST_0)
+{
+    HashTable* old_table;
+    HashTable* new_table;
+
+    if (!try_seize_update_permission(BIF_P)) {
+	ERTS_BIF_YIELD0(bif_export[BIF_erts_internal_erase_persistent_terms_0],
+                        BIF_P);
+    }
+    old_table = (HashTable *) erts_atomic_read_nob(&the_hash_table);
+    old_table->first_to_delete = 0;
+    old_table->num_to_delete = old_table->allocated;
+    new_table = create_initial_table();
+    erts_schedule_thr_prgr_later_op(table_updater, new_table, &thr_prog_op);
+    suspend_updater(BIF_P);
+    ERTS_BIF_YIELD_RETURN(BIF_P, am_true);
+}
+
+BIF_RETTYPE persistent_term_info_0(BIF_ALIST_0)
+{
+    HashTable* hash_table = (HashTable *) erts_atomic_read_nob(&the_hash_table);
+    TrapData* trap_data;
+    Eterm res = NIL;
+    Eterm magic_ref;
+    Binary* mbp;
+
+    magic_ref = alloc_trap_data(BIF_P);
+    mbp = erts_magic_ref2bin(magic_ref);
+    trap_data = ERTS_MAGIC_BIN_DATA(mbp);
+    trap_data->table = hash_table;
+    trap_data->idx = 0;
+    trap_data->remaining = hash_table->num_entries;
+    trap_data->memory = 0;
+    res = do_info(BIF_P, trap_data);
+    if (trap_data->remaining == 0) {
+        BUMP_REDS(BIF_P, hash_table->num_entries);
+        trap_data->table = NULL; /* Prevent refc decrement */
+        BIF_RET(res);
+    } else {
+        /*
+         * Increment the ref counter to prevent an update operation (by put/2
+         * or erase/1) to delete this hash table.
+         */
+        erts_atomic_inc_nob(&hash_table->refc);
+        BUMP_ALL_REDS(BIF_P);
+        BIF_TRAP2(&persistent_term_info_export, BIF_P, magic_ref, res);
+    }
+}
+
+Uint
+erts_persistent_term_count(void)
+{
+    HashTable* hash_table = (HashTable *) erts_atomic_read_nob(&the_hash_table);
+    return hash_table->num_entries;
+}
+
+void
+erts_init_persistent_dumping(void)
+{
+    HashTable* hash_table = (HashTable *) erts_atomic_read_nob(&the_hash_table);
+    ErtsLiteralArea** area_p;
+    Uint i;
+
+    /*
+     * Overwrite the array of Eterms in the current hash table
+     * with pointers to literal areas.
+     */
+
+    erts_persistent_areas = (ErtsLiteralArea **) hash_table->term;
+    erts_num_persistent_areas = hash_table->num_entries;
+    area_p = erts_persistent_areas;
+    for (i = 0; i < hash_table->allocated; i++) {
+        Eterm term = hash_table->term[i];
+
+        if (is_boxed(term)) {
+            *area_p++ = term_to_area(term);
+        }
+    }
+}
+
+/*
+ * Local functions.
+ */
+
+static HashTable*
+create_initial_table(void)
+{
+    HashTable* hash_table;
+    int i;
+
+    hash_table = (HashTable *) erts_alloc(ERTS_ALC_T_PERSISTENT_TERM,
+                                          sizeof(HashTable)+sizeof(Eterm) *
+                                          (INITIAL_SIZE-1));
+    hash_table->allocated = INITIAL_SIZE;
+    hash_table->num_entries = 0;
+    hash_table->mask = INITIAL_SIZE-1;
+    hash_table->first_to_delete = 0;
+    hash_table->num_to_delete = 0;
+    erts_atomic_init_nob(&hash_table->refc, (erts_aint_t)1);
+    for (i = 0; i < INITIAL_SIZE; i++) {
+        hash_table->term[i] = NIL;
+    }
+    return hash_table;
+}
+
+static BIF_RETTYPE
+persistent_term_get_all_trap(BIF_ALIST_2)
+{
+    TrapData* trap_data;
+    Eterm res = BIF_ARG_2;
+    Uint bump_reds;
+    Binary* mbp;
+
+    ASSERT(is_list(BIF_ARG_2));
+    mbp = erts_magic_ref2bin(BIF_ARG_1);
+    trap_data = ERTS_MAGIC_BIN_DATA(mbp);
+    bump_reds = trap_data->remaining;
+    res = do_get_all(BIF_P, trap_data, res);
+    ASSERT(is_list(res));
+    if (trap_data->remaining > 0) {
+        BUMP_ALL_REDS(BIF_P);
+        BIF_TRAP2(&persistent_term_get_all_export, BIF_P, BIF_ARG_1, res);
+    } else {
+        /*
+         * Decrement ref count (and possibly delete the hash table
+         * and associated literal area).
+         */
+        dec_table_refc(BIF_P, trap_data->table);
+        trap_data->table = NULL; /* Prevent refc decrement */
+        BUMP_REDS(BIF_P, bump_reds);
+        BIF_RET(res);
+    }
+}
+
+static Eterm
+do_get_all(Process* c_p, TrapData* trap_data, Eterm res)
+{
+    HashTable* hash_table;
+    Uint remaining;
+    Uint idx;
+    Uint max_iter;
+    Uint i;
+    Eterm* hp;
+    Uint heap_size;
+    struct copy_term {
+        Uint key_size;
+        Eterm* tuple_ptr;
+    } *copy_data;
+
+    hash_table = trap_data->table;
+    idx = trap_data->idx;
+#if defined(DEBUG) || defined(VALGRIND)
+    max_iter = 50;
+#else
+    max_iter = ERTS_BIF_REDS_LEFT(c_p);
+#endif
+    remaining = trap_data->remaining < max_iter ?
+        trap_data->remaining : max_iter;
+    trap_data->remaining -= remaining;
+
+    copy_data = (struct copy_term *) erts_alloc(ERTS_ALC_T_TMP,
+                                                remaining *
+                                                sizeof(struct copy_term));
+    i = 0;
+    heap_size = (2 + 3) * remaining;
+    while (remaining != 0) {
+        Eterm term = hash_table->term[idx];
+        if (is_tuple(term)) {
+            Uint key_size;
+            Eterm* tup_val;
+
+            ASSERT(is_tuple_arity(term, 2));
+            tup_val = tuple_val(term);
+            key_size = size_object(tup_val[1]);
+            copy_data[i].key_size = key_size;
+            copy_data[i].tuple_ptr = tup_val;
+            heap_size += key_size;
+            i++;
+            remaining--;
+        }
+        idx++;
+    }
+    trap_data->idx = idx;
+
+    hp = HAlloc(c_p, heap_size);
+    remaining = i;
+    for (i = 0; i < remaining; i++) {
+        Eterm* tuple_ptr;
+        Uint key_size;
+        Eterm key;
+        Eterm tup;
+
+        tuple_ptr = copy_data[i].tuple_ptr;
+        key_size = copy_data[i].key_size;
+        key = copy_struct(tuple_ptr[1], key_size, &hp, &c_p->off_heap);
+        tup = TUPLE2(hp, key, tuple_ptr[2]);
+        hp += 3;
+        res = CONS(hp, tup, res);
+        hp += 2;
+    }
+    erts_free(ERTS_ALC_T_TMP, copy_data);
+    return res;
+}
+
+static BIF_RETTYPE
+persistent_term_info_trap(BIF_ALIST_1)
+{
+    TrapData* trap_data = (TrapData *) BIF_ARG_1;
+    Eterm res;
+    Uint bump_reds;
+    Binary* mbp;
+
+    mbp = erts_magic_ref2bin(BIF_ARG_1);
+    trap_data = ERTS_MAGIC_BIN_DATA(mbp);
+    bump_reds = trap_data->remaining;
+    res = do_info(BIF_P, trap_data);
+    if (trap_data->remaining > 0) {
+        ASSERT(res == am_ok);
+        BUMP_ALL_REDS(BIF_P);
+        BIF_TRAP1(&persistent_term_info_export, BIF_P, BIF_ARG_1);
+    } else {
+        /*
+         * Decrement ref count (and possibly delete the hash table
+         * and associated literal area).
+         */
+        dec_table_refc(BIF_P, trap_data->table);
+        trap_data->table = NULL; /* Prevent refc decrement */
+        BUMP_REDS(BIF_P, bump_reds);
+        ASSERT(is_map(res));
+        BIF_RET(res);
+    }
+}
+
+#define DECL_AM(S) Eterm AM_ ## S = am_atom_put(#S, sizeof(#S) - 1)
+
+static Eterm
+do_info(Process* c_p, TrapData* trap_data)
+{
+    HashTable* hash_table;
+    Uint remaining;
+    Uint idx;
+    Uint max_iter;
+
+    hash_table = trap_data->table;
+    idx = trap_data->idx;
+#if defined(DEBUG) || defined(VALGRIND)
+    max_iter = 50;
+#else
+    max_iter = ERTS_BIF_REDS_LEFT(c_p);
+#endif
+    remaining = trap_data->remaining < max_iter ? trap_data->remaining : max_iter;
+    trap_data->remaining -= remaining;
+    while (remaining != 0) {
+        if (is_boxed(hash_table->term[idx])) {
+            ErtsLiteralArea* area;
+            area = term_to_area(hash_table->term[idx]);
+            trap_data->memory += sizeof(ErtsLiteralArea) +
+                sizeof(Eterm) * (area->end - area->start - 1);
+            remaining--;
+        }
+        idx++;
+    }
+    trap_data->idx = idx;
+    if (trap_data->remaining > 0) {
+        return am_ok;           /* Dummy return value */
+    } else {
+        Eterm* hp;
+        Eterm count_term;
+        Eterm memory_term;
+        Eterm res;
+        Uint memory;
+        Uint hsz = MAP_SZ(2);
+
+        memory = sizeof(HashTable) + (trap_data->table->allocated-1) *
+            sizeof(Eterm) + trap_data->memory;
+        (void) erts_bld_uint(NULL, &hsz, hash_table->num_entries);
+        (void) erts_bld_uint(NULL, &hsz, memory);
+        hp = HAlloc(c_p, hsz);
+	count_term = erts_bld_uint(&hp, NULL, hash_table->num_entries);
+	memory_term = erts_bld_uint(&hp, NULL, memory);
+        res = MAP2(hp, am_count, count_term, am_memory, memory_term);
+        return res;
+    }
+}
+
+#undef DECL_AM
+
+static Eterm
+alloc_trap_data(Process* c_p)
+{
+    Binary* mbp = erts_create_magic_binary(sizeof(TrapData),
+                                           cleanup_trap_data);
+    Eterm* hp;
+
+    hp = HAlloc(c_p, ERTS_MAGIC_REF_THING_SIZE);
+    return erts_mk_magic_ref(&hp, &MSO(c_p), mbp);
+}
+
+static int
+cleanup_trap_data(Binary *bp)
+{
+    TrapData* trap_data = ERTS_MAGIC_BIN_DATA(bp);
+
+    if (trap_data->table) {
+        /*
+         * The process has been killed and is now exiting.
+         * Decrement the reference counter for the table.
+         */
+        dec_table_refc(NULL, trap_data->table);
+    }
+    return 1;
+}
+
+static Uint
+lookup(HashTable* hash_table, Eterm key)
+{
+    Uint mask = hash_table->mask;
+    Eterm* table = hash_table->term;
+    Uint32 idx = make_internal_hash(key, 0);
+    Eterm term;
+
+    do {
+        idx++;
+        term = table[idx & mask];
+    } while (is_boxed(term) && !EQ(key, (tuple_val(term))[1]));
+    return idx & mask;
+}
+
+static HashTable*
+tmp_table_copy(HashTable* old_table)
+{
+    Uint size = old_table->allocated;
+    HashTable* tmp_table;
+    Uint i;
+
+    tmp_table = (HashTable *) erts_alloc(ERTS_ALC_T_TMP,
+                                         sizeof(HashTable) +
+                                         sizeof(Eterm) * (size-1));
+    *tmp_table = *old_table;
+    for (i = 0; i < size; i++) {
+        tmp_table->term[i] = old_table->term[i];
+    }
+    return tmp_table;
+}
+
+static HashTable*
+copy_table(HashTable* old_table, Uint new_size, int rehash)
+{
+    HashTable* new_table;
+    Uint old_size = old_table->allocated;
+    Uint i;
+
+    new_table = (HashTable *) erts_alloc(ERTS_ALC_T_PERSISTENT_TERM,
+                                         sizeof(HashTable) +
+                                         sizeof(Eterm) * (new_size-1));
+    if (old_table->allocated == new_size && !rehash) {
+        /*
+         * Same size and no key deleted. Make an exact copy of the table.
+         */
+        *new_table = *old_table;
+        for (i = 0; i < new_size; i++) {
+            new_table->term[i] = old_table->term[i];
+        }
+    } else {
+        /*
+         * The size of the table has changed or an element has been
+         * deleted. Must rehash, by inserting all old terms into the
+         * new (empty) table.
+         */
+        new_table->allocated = new_size;
+        new_table->num_entries = old_table->num_entries;
+        new_table->mask = new_size - 1;
+        for (i = 0; i < new_size; i++) {
+            new_table->term[i] = NIL;
+        }
+        for (i = 0; i < old_size; i++) {
+            if (is_tuple(old_table->term[i])) {
+                Eterm key = tuple_val(old_table->term[i])[1];
+                Uint entry_index = lookup(new_table, key);
+                ASSERT(is_nil(new_table->term[entry_index]));
+                new_table->term[entry_index] = old_table->term[i];
+            }
+        }
+    }
+    new_table->first_to_delete = 0;
+    new_table->num_to_delete = 0;
+    erts_atomic_init_nob(&new_table->refc, (erts_aint_t)1);
+    return new_table;
+}
+
+static void
+mark_for_deletion(HashTable* hash_table, Uint entry_index)
+{
+    hash_table->first_to_delete = entry_index;
+    hash_table->num_to_delete = 1;
+}
+
+static ErtsLiteralArea*
+term_to_area(Eterm tuple)
+{
+    ASSERT(is_tuple_arity(tuple, 2));
+    return (ErtsLiteralArea *) (((char *) tuple_val(tuple)) -
+                                offsetof(ErtsLiteralArea, start));
+}
+
+static void
+table_updater(void* data)
+{
+    HashTable* old_table;
+    HashTable* new_table;
+
+    old_table = (HashTable *) erts_atomic_read_nob(&the_hash_table);
+    new_table = (HashTable *) data;
+    ASSERT(new_table->num_to_delete == 0);
+    erts_atomic_set_nob(&the_hash_table, (erts_aint_t)new_table);
+    append_to_delete_queue(old_table);
+    erts_schedule_thr_prgr_later_op(table_deleter,
+                                    old_table,
+                                    &old_table->thr_prog_op);
+    release_update_permission(1);
+}
+
+static void
+table_deleter(void* data)
+{
+    HashTable* old_table = (HashTable *) data;
+
+    dec_table_refc(NULL, old_table);
+}
+
+static void
+dec_table_refc(Process* c_p, HashTable* old_table)
+{
+    erts_aint_t refc = erts_atomic_dec_read_nob(&old_table->refc);
+
+    if (refc == 0) {
+        HashTable* to_delete;
+
+        while ((to_delete = next_to_delete()) != NULL) {
+            delete_table(c_p, to_delete);
+        }
+    }
+}
+
+static void
+delete_table(Process* c_p, HashTable* table)
+{
+    Uint idx = table->first_to_delete;
+    Uint n = table->num_to_delete;
+
+    /*
+     * There are no longer any references to this hash table.
+     *
+     * Any literals pointed for deletion can be queued for
+     * deletion and the table itself can be deallocated.
+     */
+
+#ifdef DEBUG
+    if (n == 1) {
+        ASSERT(is_tuple_arity(table->term[idx], 2));
+    }
+#endif
+
+    while (n > 0) {
+        Eterm term = table->term[idx];
+
+        if (is_tuple_arity(term, 2)) {
+            if (is_immed(tuple_val(term)[2])) {
+                erts_release_literal_area(term_to_area(term));
+            } else {
+                erts_queue_release_literals(c_p, term_to_area(term));
+            }
+        }
+        idx++, n--;
+    }
+    erts_free(ERTS_ALC_T_PERSISTENT_TERM, table);
+}
+
+/*
+ * Caller *must* yield if this function returns 0.
+ */
+
+static int
+try_seize_update_permission(Process* c_p)
+{
+    int success;
+
+    ASSERT(!erts_thr_progress_is_blocking()); /* to avoid deadlock */
+    ASSERT(c_p != NULL);
+
+    erts_mtx_lock(&update_table_permission_mtx);
+    ASSERT(updater_process != c_p);
+    success = (updater_process == NULL);
+    if (success) {
+        updater_process = c_p;
+    } else {
+        struct update_queue_item* qitem;
+        qitem = erts_alloc(ERTS_ALC_T_PERSISTENT_LOCK_Q, sizeof(*qitem));
+        qitem->p = c_p;
+        erts_proc_inc_refc(c_p);
+        qitem->next = update_queue;
+        update_queue = qitem;
+        erts_suspend(c_p, ERTS_PROC_LOCK_MAIN, NULL);
+    }
+    erts_mtx_unlock(&update_table_permission_mtx);
+    return success;
+}
+
+static void
+release_update_permission(int release_updater)
+{
+    erts_mtx_lock(&update_table_permission_mtx);
+    ASSERT(updater_process != NULL);
+
+    if (release_updater) {
+        erts_proc_lock(updater_process, ERTS_PROC_LOCK_STATUS);
+        if (!ERTS_PROC_IS_EXITING(updater_process)) {
+            erts_resume(updater_process, ERTS_PROC_LOCK_STATUS);
+        }
+        erts_proc_unlock(updater_process, ERTS_PROC_LOCK_STATUS);
+    }
+    updater_process = NULL;
+
+    while (update_queue != NULL) { /* Unleash the entire herd */
+	struct update_queue_item* qitem = update_queue;
+	erts_proc_lock(qitem->p, ERTS_PROC_LOCK_STATUS);
+	if (!ERTS_PROC_IS_EXITING(qitem->p)) {
+	    erts_resume(qitem->p, ERTS_PROC_LOCK_STATUS);
+	}
+	erts_proc_unlock(qitem->p, ERTS_PROC_LOCK_STATUS);
+	update_queue = qitem->next;
+	erts_proc_dec_refc(qitem->p);
+	erts_free(ERTS_ALC_T_PERSISTENT_LOCK_Q, qitem);
+    }
+    erts_mtx_unlock(&update_table_permission_mtx);
+}
+
+static void
+suspend_updater(Process* c_p)
+{
+#ifdef DEBUG
+    ASSERT(c_p != NULL);
+    erts_mtx_lock(&update_table_permission_mtx);
+    ASSERT(updater_process == c_p);
+    erts_mtx_unlock(&update_table_permission_mtx);
+#endif
+    erts_suspend(c_p, ERTS_PROC_LOCK_MAIN, NULL);
+}
+
+static void
+append_to_delete_queue(HashTable* table)
+{
+    erts_mtx_lock(&delete_queue_mtx);
+    table->delete_next = NULL;
+    *delete_queue_tail = table;
+    delete_queue_tail = &table->delete_next;
+    erts_mtx_unlock(&delete_queue_mtx);
+}
+
+static HashTable*
+next_to_delete(void)
+{
+    HashTable* table;
+
+    erts_mtx_lock(&delete_queue_mtx);
+    table = delete_queue_head;
+    if (table) {
+        if (erts_atomic_read_nob(&table->refc)) {
+            /*
+             * This hash table is still referenced. Hash tables
+             * must be deleted in order, so we return a NULL
+             * pointer.
+             */
+            table = NULL;
+        } else {
+            /*
+             * Remove the first hash table from the queue.
+             */
+            delete_queue_head = table->delete_next;
+            if (delete_queue_head == NULL) {
+                delete_queue_tail = &delete_queue_head;
+            }
+        }
+    }
+    erts_mtx_unlock(&delete_queue_mtx);
+    return table;
+}
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 57c6c10c7f..f687dcf335 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -354,6 +354,7 @@ erl_init(int ncpu,
     erts_init_bif();
     erts_init_bif_chksum();
     erts_init_bif_binary();
+    erts_init_bif_persistent_term();
     erts_init_bif_re();
     erts_init_unicode(); /* after RE to get access to PCRE unicode */
     erts_init_external();
diff --git a/erts/emulator/beam/erl_lock_check.c b/erts/emulator/beam/erl_lock_check.c
index 463ae898a3..1416c5f96c 100644
--- a/erts/emulator/beam/erl_lock_check.c
+++ b/erts/emulator/beam/erl_lock_check.c
@@ -97,6 +97,8 @@ static erts_lc_lock_order_t erts_lock_order[] = {
     {	"proc_btm",				"pid"			},
     {	"dist_entry",				"address"		},
     {	"dist_entry_links",			"address"		},
+    {   "update_persistent_term_permission",    NULL                    },
+    {   "persistent_term_delete_permission",    NULL                    },
     {   "code_write_permission",                NULL                    },
     {	"purge_state",		      		NULL			},
     {	"proc_status",				"pid"			},
diff --git a/erts/emulator/beam/erl_process_dump.c b/erts/emulator/beam/erl_process_dump.c
index 243db4c734..ac5054ea10 100644
--- a/erts/emulator/beam/erl_process_dump.c
+++ b/erts/emulator/beam/erl_process_dump.c
@@ -58,6 +58,7 @@ static void dump_externally(fmtfn_t to, void *to_arg, Eterm term);
 static void mark_literal(Eterm* ptr);
 static void init_literal_areas(void);
 static void dump_literals(fmtfn_t to, void *to_arg);
+static void dump_persistent_terms(fmtfn_t to, void *to_arg);
 static void dump_module_literals(fmtfn_t to, void *to_arg,
                                  ErtsLiteralArea* lit_area);
 
@@ -74,6 +75,7 @@ erts_deep_process_dump(fmtfn_t to, void *to_arg)
 
     all_binaries = NULL;
     init_literal_areas();
+    erts_init_persistent_dumping();
 
     for (i = 0; i < max; i++) {
 	Process *p = erts_pix2proc(i);
@@ -93,6 +95,7 @@ erts_deep_process_dump(fmtfn_t to, void *to_arg)
        }
     }
 
+    dump_persistent_terms(to, to_arg);
     dump_literals(to, to_arg);
     dump_binaries(to, to_arg, all_binaries);
 }
@@ -775,6 +778,9 @@ init_literal_areas(void)
     qsort(lit_areas, num_lit_areas, sizeof(ErtsLiteralArea *),
           compare_areas);
 
+    qsort(erts_persistent_areas, erts_num_persistent_areas,
+          sizeof(ErtsLiteralArea *), compare_areas);
+
     erts_runlock_old_code(code_ix);
 }
 
@@ -796,6 +802,13 @@ static void mark_literal(Eterm* ptr)
 
     ap = bsearch(ptr, lit_areas, num_lit_areas, sizeof(ErtsLiteralArea*),
                  search_areas);
+    if (ap == 0) {
+        ap = bsearch(ptr, erts_persistent_areas,
+                     erts_num_persistent_areas,
+                     sizeof(ErtsLiteralArea*),
+                     search_areas);
+    }
+
 
     /*
      * If the literal was created by native code, this search will not
@@ -807,12 +820,12 @@ static void mark_literal(Eterm* ptr)
     }
 }
 
-
 static void
 dump_literals(fmtfn_t to, void *to_arg)
 {
     ErtsCodeIndex code_ix;
     int i;
+    Uint idx;
 
     code_ix = erts_active_code_ix();
     erts_rlock_old_code(code_ix);
@@ -825,6 +838,28 @@ dump_literals(fmtfn_t to, void *to_arg)
     }
 
     erts_runlock_old_code(code_ix);
+
+    for (idx = 0; idx < erts_num_persistent_areas; idx++) {
+        dump_module_literals(to, to_arg, erts_persistent_areas[idx]);
+    }
+}
+
+static void
+dump_persistent_terms(fmtfn_t to, void *to_arg)
+{
+    Uint idx;
+
+    erts_print(to, to_arg, "=persistent_terms\n");
+
+    for (idx = 0; idx < erts_num_persistent_areas; idx++) {
+        ErtsLiteralArea* ap = erts_persistent_areas[idx];
+        Eterm tuple = make_tuple(ap->start);
+        Eterm* tup_val = tuple_val(tuple);
+
+	dump_element(to, to_arg, tup_val[1]);
+        erts_putc(to, to_arg, '|');
+	dump_element_nl(to, to_arg, tup_val[2]);
+    }
 }
 
 static void
@@ -963,7 +998,8 @@ dump_module_literals(fmtfn_t to, void *to_arg, ErtsLiteralArea* lit_area)
                     }
                     erts_putc(to, to_arg, '\n');
                 }
-            } else if (is_export_header(w)) {
+            } else {
+                /* Dump everything else in the external format */
                 dump_externally(to, to_arg, term);
                 erts_putc(to, to_arg, '\n');
             }
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 21ae205237..0631404599 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -906,6 +906,8 @@ typedef struct ErtsLiteralArea_ {
     Eterm start[1]; /* beginning of area */
 } ErtsLiteralArea;
 
+void erts_queue_release_literals(Process *c_p, ErtsLiteralArea* literals);
+
 #define ERTS_LITERAL_AREA_ALLOC_SIZE(N) \
     (sizeof(ErtsLiteralArea) + sizeof(Eterm)*((N) - 1))
 
@@ -1001,6 +1003,7 @@ typedef struct {
     Uint literal_size;
     Eterm *lit_purge_ptr;
     Uint lit_purge_sz;
+    int copy_literals;
 } erts_shcopy_t;
 
 #define INITIALIZE_SHCOPY(info)						\
@@ -1010,6 +1013,7 @@ typedef struct {
 	info.bitstore_start = info.bitstore_default;			\
 	info.shtable_start = info.shtable_default;			\
 	info.literal_size = 0;						\
+	info.copy_literals = 0;						\
 	if (larea__) {							\
 	    info.lit_purge_ptr = &larea__->start[0];			\
 	    info.lit_purge_sz = larea__->end - info.lit_purge_ptr;	\
@@ -1238,6 +1242,13 @@ Sint erts_re_set_loop_limit(Sint limit);
 void erts_init_bif_binary(void);
 Sint erts_binary_set_loop_limit(Sint limit);
 
+/* erl_bif_persistent.c */
+void erts_init_bif_persistent_term(void);
+Uint erts_persistent_term_count(void);
+void erts_init_persistent_dumping(void);
+extern ErtsLiteralArea** erts_persistent_areas;
+extern Uint erts_num_persistent_areas;
+
 /* external.c */
 void erts_init_external(void);
 
diff --git a/erts/emulator/test/Makefile b/erts/emulator/test/Makefile
index bf00de2204..d201ea6ee1 100644
--- a/erts/emulator/test/Makefile
+++ b/erts/emulator/test/Makefile
@@ -92,6 +92,7 @@ MODULES= \
 	port_SUITE \
 	port_bif_SUITE \
 	prim_eval_SUITE \
+	persistent_term_SUITE \
 	process_SUITE \
 	pseudoknot_SUITE \
 	receive_SUITE \
diff --git a/erts/emulator/test/persistent_term_SUITE.erl b/erts/emulator/test/persistent_term_SUITE.erl
new file mode 100644
index 0000000000..58cd3276b0
--- /dev/null
+++ b/erts/emulator/test/persistent_term_SUITE.erl
@@ -0,0 +1,614 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2017. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%5
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(persistent_term_SUITE).
+-include_lib("common_test/include/ct.hrl").
+
+-export([all/0,suite/0,
+	 basic/1,purging/1,sharing/1,get_trapping/1,
+         info/1,info_trapping/1,killed_while_trapping/1,
+         off_heap_values/1,keys/1,collisions/1,
+         init_restart/1]).
+
+%%
+-export([test_init_restart_cmd/1]).
+
+suite() ->
+    [{ct_hooks,[ts_install_cth]},
+     {timetrap,{minutes,10}}].
+
+all() ->
+    [basic,purging,sharing,get_trapping,info,info_trapping,
+     killed_while_trapping,off_heap_values,keys,collisions,
+     init_restart].
+
+basic(_Config) ->
+    Chk = chk(),
+    N = 777,
+    Seq = lists:seq(1, N),
+    par(2, N, Seq),
+    seq(3, Seq),
+    seq(3, Seq),                                %Same values.
+    _ = [begin
+             Key = {?MODULE,{key,I}},
+             true = persistent_term:erase(Key),
+             false = persistent_term:erase(Key),
+             {'EXIT',{badarg,_}} = (catch persistent_term:get(Key))
+         end || I <- Seq],
+    [] = [P || {{?MODULE,_},_}=P <- persistent_term:get()],
+    chk(Chk).
+
+par(C, N, Seq) ->
+    _ = [spawn_link(fun() ->
+                            ok = persistent_term:put({?MODULE,{key,I}},
+                                                     {value,C*I})
+                    end) || I <- Seq],
+    Result = wait(N),
+    _ = [begin
+             Double = C*I,
+             {{?MODULE,{key,I}},{value,Double}} = Res
+         end || {I,Res} <- lists:zip(Seq, Result)],
+    ok.
+
+seq(C, Seq) ->
+    _ = [ok = persistent_term:put({?MODULE,{key,I}}, {value,C*I}) ||
+            I <- Seq],
+    All = persistent_term:get(),
+    All = [P || {{?MODULE,_},_}=P <- persistent_term:get()],
+    All = [{Key,persistent_term:get(Key)} || {Key,_} <- All],
+    Result = lists:sort(All),
+    _ = [begin
+             Double = C*I,
+             {{?MODULE,{key,I}},{value,Double}} = Res
+         end || {I,Res} <- lists:zip(Seq, Result)],
+    ok.
+
+wait(N) ->
+    All = [P || {{?MODULE,_},_}=P <- persistent_term:get()],
+    case length(All) of
+        N ->
+            All = [{Key,persistent_term:get(Key)} || {Key,_} <- All],
+            lists:sort(All);
+        _ ->
+            receive after 10 -> ok end,
+            wait(N)
+    end.
+
+%% Make sure that terms that have been erased are copied into all
+%% processes that still hold a pointer to them.
+
+purging(_Config) ->
+    Chk = chk(),
+    do_purging(fun(K) -> persistent_term:put(K, {?MODULE,new}) end,
+               replaced),
+    do_purging(fun persistent_term:erase/1, erased),
+    chk(Chk).
+
+do_purging(Eraser, Type) ->
+    Parent = self(),
+    Key = {?MODULE,?FUNCTION_NAME},
+    ok = persistent_term:put(Key, {term,[<<"abc",0:777/unit:8>>]}),
+    Ps0 = [spawn_monitor(fun() -> purging_tester(Parent, Key) end) ||
+              _ <- lists:seq(1, 50)],
+    Ps = maps:from_list(Ps0),
+    purging_recv(gotten, Ps),
+    Eraser(Key),
+    _ = [P ! {Parent,Type} || P <- maps:keys(Ps)],
+    purging_wait(Ps).
+
+purging_recv(Tag, Ps) when map_size(Ps) > 0 ->
+    receive
+        {Pid,Tag} ->
+            true = is_map_key(Pid, Ps),
+            purging_recv(Tag, maps:remove(Pid, Ps))
+    end;
+purging_recv(_, _) -> ok.
+
+purging_wait(Ps) when map_size(Ps) > 0 ->
+    receive
+        {'DOWN',Ref,process,Pid,Reason} ->
+            normal = Reason,
+            Ref = map_get(Pid, Ps),
+            purging_wait(maps:remove(Pid, Ps))
+    end;
+purging_wait(_) -> ok.
+
+purging_tester(Parent, Key) ->
+    Term = persistent_term:get(Key),
+    purging_check_term(Term),
+    0 = erts_debug:size_shared(Term),
+    Parent ! {self(),gotten},
+    receive
+        {Parent,erased} ->
+            {'EXIT',{badarg,_}} = (catch persistent_term:get(Key)),
+            purging_tester_1(Term);
+        {Parent,replaced} ->
+            {?MODULE,new} = persistent_term:get(Key),
+            purging_tester_1(Term)
+    end.
+
+%% Wait for the term to be copied into this process.
+purging_tester_1(Term) ->
+    purging_check_term(Term),
+    receive after 1 -> ok end,
+    case erts_debug:size_shared(Term) of
+        0 ->
+            purging_tester_1(Term);
+        Size ->
+            %% The term has been copied into this process.
+            purging_check_term(Term),
+            Size = erts_debug:size(Term)
+    end.
+
+purging_check_term({term,[<<"abc",0:777/unit:8>>]}) ->
+    ok.
+
+%% Test that sharing is preserved when storing terms.
+
+sharing(_Config) ->
+    Chk = chk(),
+    Depth = 10,
+    Size = 2*Depth,
+    Shared = lists:foldl(fun(_, A) -> [A|A] end,
+                         [], lists:seq(1, Depth)),
+    Size = erts_debug:size(Shared),
+    Key = {?MODULE,?FUNCTION_NAME},
+    ok = persistent_term:put(Key, Shared),
+    SharedStored = persistent_term:get(Key),
+    Size = erts_debug:size(SharedStored),
+    0 = erts_debug:size_shared(SharedStored),
+
+    {Pid,Ref} = spawn_monitor(fun() ->
+                                      Term = persistent_term:get(Key),
+                                      Size = erts_debug:size(Term),
+                                      0 = erts_debug:size_shared(Term),
+                                      true = Term =:= SharedStored
+                              end),
+    receive
+        {'DOWN',Ref,process,Pid,normal} ->
+            true = persistent_term:erase(Key),
+            Size = erts_debug:size(SharedStored),
+            chk(Chk)
+    end.
+
+%% Test trapping of persistent_term:get/0.
+
+get_trapping(_Config) ->
+    Chk = chk(),
+
+    %% Assume that the get/0 traps after 4000 iterations
+    %% in a non-debug emulator.
+    N = case test_server:timetrap_scale_factor() of
+            1 -> 10000;
+            _ -> 1000
+        end,
+    spawn_link(fun() -> get_trapping_create(N) end),
+    All = do_get_trapping(N, []),
+    N = get_trapping_check_result(lists:sort(All), 1),
+    erlang:garbage_collect(),
+    get_trapping_erase(N),
+    chk(Chk).
+
+do_get_trapping(N, Prev) ->
+    case persistent_term:get() of
+        Prev when length(Prev) >= N ->
+            All = [P || {{?MODULE,{get_trapping,_}},_}=P <- Prev],
+            case length(All) of
+                N -> All;
+                _ -> do_get_trapping(N, Prev)
+            end;
+        New ->
+            receive after 1 -> ok end,
+            do_get_trapping(N, New)
+    end.
+
+get_trapping_create(0) ->
+    ok;
+get_trapping_create(N) ->
+    ok = persistent_term:put({?MODULE,{get_trapping,N}}, N),
+    get_trapping_create(N-1).
+
+get_trapping_check_result([{{?MODULE,{get_trapping,N}},N}|T], N) ->
+    get_trapping_check_result(T, N+1);
+get_trapping_check_result([], N) -> N-1.
+
+get_trapping_erase(0) ->
+    ok;
+get_trapping_erase(N) ->
+    true = persistent_term:erase({?MODULE,{get_trapping,N}}),
+    get_trapping_erase(N-1).
+
+%% Test retrieving information about persistent terms.
+
+info(_Config) ->
+    Chk = chk(),
+
+    %% White box test of info/0.
+    N = 100,
+    try
+        Overhead = info_literal_area_overhead(),
+        io:format("Overhead = ~p\n", [Overhead]),
+        info_wb(N, Overhead, info_info())
+    after
+        _ = [_ = persistent_term:erase({?MODULE,I}) ||
+                I <- lists:seq(1, N)]
+    end,
+
+    chk(Chk).
+
+%% White box test of persistent_term:info/0. We take into account
+%% that there might already exist persistent terms (created by the
+%% OTP standard libraries), but we assume that they are not
+%% changed during the execution of this test case.
+
+info_wb(0, _, _) ->
+    ok;
+info_wb(N, Overhead, {BaseCount,BaseMemory}) ->
+    Key = {?MODULE,N},
+    Value = lists:seq(1, N),
+    ok = persistent_term:put(Key, Value),
+
+    %% Calculate the extra memory needed for this term.
+    WordSize = erlang:system_info(wordsize),
+    ExtraMemory = Overhead + 2 * N * WordSize,
+
+    %% Call persistent_term:info/0.
+    {Count,Memory} = info_info(),
+
+    %% There should be one more persistent term.
+    Count = BaseCount + 1,
+
+    %% Verify that the amount of memory is correct.
+    case BaseMemory + ExtraMemory of
+        Memory ->
+            %% Exactly right. The size of the hash table was not changed.
+            ok;
+        Expected ->
+            %% The size of the hash table has been doubled to avoid filling
+            %% the table to more than 50 percent. The previous number
+            %% of entries must have been exactly half the size of the
+            %% hash table. The expected number of extra words added by
+            %% the resizing will be twice that number.
+            ExtraWords = BaseCount * 2,
+            true = ExtraWords * WordSize =:= (Memory - Expected)
+    end,
+    info_wb(N-1, Overhead, {Count,Memory}).
+
+info_info() ->
+    #{count:=Count,memory:=Memory} = persistent_term:info(),
+    true = is_integer(Count) andalso Count >= 0,
+    true = is_integer(Memory) andalso Memory >= 0,
+    {Count,Memory}.
+
+%% Calculate the number of extra bytes needed for storing each term in
+%% the literal, assuming that the key is a tuple of size 2 with
+%% immediate elements. The calculated number is the size of the
+%% ErtsLiteralArea struct excluding the storage for the literal term
+%% itself.
+
+info_literal_area_overhead() ->
+    Key1 = {?MODULE,1},
+    Key2 = {?MODULE,2},
+    #{memory:=Mem0} = persistent_term:info(),
+    ok = persistent_term:put(Key1, literal),
+    #{memory:=Mem1} = persistent_term:info(),
+    ok = persistent_term:put(Key2, literal),
+    #{memory:=Mem2} = persistent_term:info(),
+    true = persistent_term:erase(Key1),
+    true = persistent_term:erase(Key2),
+
+    %% The size of the hash table may have doubled when inserting
+    %% one of the keys. To avoiding counting the change in the hash
+    %% table size, take the smaller size increase.
+    min(Mem2-Mem1, Mem1-Mem0).
+
+%% Test trapping of persistent_term:info/0.
+
+info_trapping(_Config) ->
+    Chk = chk(),
+
+    %% Assume that the info/0 traps after 4000 iterations
+    %% in a non-debug emulator.
+    N = case test_server:timetrap_scale_factor() of
+            1 -> 10000;
+            _ -> 1000
+        end,
+    spawn_link(fun() -> info_trapping_create(N) end),
+    All = do_info_trapping(N, 0),
+    N = info_trapping_check_result(lists:sort(All), 1),
+    erlang:garbage_collect(),
+    info_trapping_erase(N),
+    chk(Chk).
+
+do_info_trapping(N, PrevMem) ->
+    case info_info() of
+        {N,Mem} ->
+            true = Mem >= PrevMem,
+            All = [P || {{?MODULE,{info_trapping,_}},_}=P <- persistent_term:get()],
+            case length(All) of
+                N -> All;
+                _ -> do_info_trapping(N, PrevMem)
+            end;
+        {_,Mem} ->
+            true = Mem >= PrevMem,
+            receive after 1 -> ok end,
+            do_info_trapping(N, Mem)
+    end.
+
+info_trapping_create(0) ->
+    ok;
+info_trapping_create(N) ->
+    ok = persistent_term:put({?MODULE,{info_trapping,N}}, N),
+    info_trapping_create(N-1).
+
+info_trapping_check_result([{{?MODULE,{info_trapping,N}},N}|T], N) ->
+    info_trapping_check_result(T, N+1);
+info_trapping_check_result([], N) -> N-1.
+
+info_trapping_erase(0) ->
+    ok;
+info_trapping_erase(N) ->
+    true = persistent_term:erase({?MODULE,{info_trapping,N}}),
+    info_trapping_erase(N-1).
+
+%% Test that hash tables are deallocated if a process running
+%% persistent_term:get/0 is killed.
+
+killed_while_trapping(_Config) ->
+    Chk = chk(),
+    N = case test_server:timetrap_scale_factor() of
+            1 -> 20000;
+            _ -> 2000
+        end,
+    kwt_put(N),
+    kwt_spawn(10),
+    kwt_erase(N),
+    chk(Chk).
+
+kwt_put(0) ->
+    ok;
+kwt_put(N) ->
+    ok = persistent_term:put({?MODULE,{kwt,N}}, N),
+    kwt_put(N-1).
+
+kwt_spawn(0) ->
+    ok;
+kwt_spawn(N) ->
+    Pids = [spawn(fun kwt_getter/0) || _ <- lists:seq(1, 20)],
+    erlang:yield(),
+    _ = [exit(Pid, kill) || Pid <- Pids],
+    kwt_spawn(N-1).
+
+kwt_getter() ->
+    _ = persistent_term:get(),
+    kwt_getter().
+
+kwt_erase(0) ->
+    ok;
+kwt_erase(N) ->
+    true = persistent_term:erase({?MODULE,{kwt,N}}),
+    kwt_erase(N-1).
+
+%% Test storing off heap values (such as ref-counted binaries).
+
+off_heap_values(_Config) ->
+    Chk = chk(),
+    Key = {?MODULE,?FUNCTION_NAME},
+    Val = {a,list_to_binary(lists:seq(0, 255)),make_ref(),fun() -> ok end},
+    ok = persistent_term:put(Key, Val),
+    FetchedVal = persistent_term:get(Key),
+    Val = FetchedVal,
+    true = persistent_term:erase(Key),
+    off_heap_values_wait(FetchedVal, Val),
+    chk(Chk).
+
+off_heap_values_wait(FetchedVal, Val) ->
+    case erts_debug:size_shared(FetchedVal) of
+        0 ->
+            Val = FetchedVal,
+            ok;
+        _ ->
+            erlang:yield(),
+            off_heap_values_wait(FetchedVal, Val)
+    end.
+
+%% Test some more data types as keys. Use the module name as a key
+%% to minimize the risk of collision with any key used
+%% by the OTP libraries.
+
+keys(_Config) ->
+    Chk = chk(),
+    do_key(?MODULE),
+    do_key([?MODULE]),
+    do_key(?MODULE_STRING),
+    do_key(list_to_binary(?MODULE_STRING)),
+    chk(Chk).
+
+do_key(Key) ->
+    Val = term_to_binary(Key),
+    ok = persistent_term:put(Key, Val),
+    StoredVal = persistent_term:get(Key),
+    Val = StoredVal,
+    true = persistent_term:erase(Key).
+
+%% Create persistent terms with keys that are known to collide.
+%% Delete them in random order, making sure that all others
+%% terms can still be found.
+
+collisions(_Config) ->
+    Chk = chk(),
+
+    %% Create persistent terms with random keys.
+    Keys = lists:flatten(colliding_keys()),
+    Kvs = [{K,rand:uniform(1000)} || K <- Keys],
+    _ = [ok = persistent_term:put(K, V) || {K,V} <- Kvs],
+    _ = [V = persistent_term:get(K) || {K,V} <- Kvs],
+
+    %% Now delete the persistent terms in random order.
+    collisions_delete(lists:keysort(2, Kvs)),
+
+    chk(Chk).
+
+collisions_delete([{Key,Val}|Kvs]) ->
+    Val = persistent_term:get(Key),
+    true = persistent_term:erase(Key),
+    true = lists:sort(persistent_term:get()) =:= lists:sort(Kvs),
+    _ = [V = persistent_term:get(K) || {K,V} <- Kvs],
+    collisions_delete(Kvs);
+collisions_delete([]) ->
+    ok.
+
+colliding_keys() ->
+    %% Collisions found by Jesper L. Andersen for breaking maps.
+    L = [[764492191,2361333849],
+         [49527266765044,90940896816021,20062927283041,267080852079651],
+         [249858369443708,206247021789428,20287304470696,25847120931175],
+         [10645228898670,224705626119556,267405565521452,258214397180678],
+         [264783762221048,166955943492306,98802957003141,102012488332476],
+         [69425677456944,177142907243411,137138950917722,228865047699598],
+         [116031213307147,29203342183358,37406949328742,255198080174323],
+         [200358182338308,235207156008390,120922906095920,116215987197289],
+         [58728890318426,68877471005069,176496507286088,221041411345780],
+         [91094120814795,50665258299931,256093108116737,19777509566621],
+         [74646746200247,98350487270564,154448261001199,39881047281135],
+         [23408943649483,164410325820923,248161749770122,274558342231648],
+         [169531547115055,213630535746863,235098262267796,200508473898303],
+         [235098564415817,85039146398174,51721575960328,173069189684390],
+         [176136386396069,155368359051606,147817099696487,265419485459634],
+         [137542881551462,40028925519736,70525669519846,63445773516557],
+         [173854695142814,114282444507812,149945832627054,99605565798831],
+         [177686773562184,127158716984798,132495543008547],
+         [227073396444896,139667311071766,158915951283562],
+         [26212438434289,94902985796531,198145776057315],
+         [266279278943923,58550737262493,74297973216378],
+         [32373606512065,131854353044428,184642643042326],
+         [34335377662439,85341895822066,273492717750246]],
+
+    %% Verify that the keys still collide (this will fail if the
+    %% internal hash function has been changed).
+    erts_debug:set_internal_state(available_internal_state, true),
+    try
+        case erlang:system_info(wordsize) of
+            8 ->
+                verify_colliding_keys(L);
+            4 ->
+                %% Not guaranteed to collide on a 32-bit system.
+                ok
+        end
+    after
+        erts_debug:set_internal_state(available_internal_state, false)
+    end,
+
+    L.
+
+verify_colliding_keys([[K|Ks]|Gs]) ->
+    Hash = internal_hash(K),
+    [Hash] = lists:usort([internal_hash(Key) || Key <- Ks]),
+    verify_colliding_keys(Gs);
+verify_colliding_keys([]) ->
+    ok.
+
+internal_hash(Term) ->
+    erts_debug:get_internal_state({internal_hash,Term}).
+
+%% Test that all persistent terms are erased by init:restart/0.
+
+init_restart(_Config) ->
+    File = "command_file",
+    ok = file:write_file(File, term_to_binary(restart)),
+    {ok,[[Erl]]} = init:get_argument(progname),
+    ModPath = filename:dirname(code:which(?MODULE)),
+    Cmd = Erl ++ " -pa " ++ ModPath ++ " -noshell "
+        "-run " ++ ?MODULE_STRING ++ " test_init_restart_cmd " ++
+        File,
+    io:format("~s\n", [Cmd]),
+    Expected = "12ok",
+    case os:cmd(Cmd) of
+        Expected ->
+            ok;
+        Actual ->
+            io:format("Expected: ~s", [Expected]),
+            io:format("Actual:   ~s\n", [Actual]),
+            ct:fail(unexpected_output)
+    end.
+
+test_init_restart_cmd([File]) ->
+    try
+        do_test_init_restart_cmd(File)
+    catch
+        C:R ->
+            io:format("\n~p ~p\n", [C,R]),
+            halt()
+    end,
+    receive
+        _ -> ok
+    end.
+
+do_test_init_restart_cmd(File) ->
+    {ok,Bin} = file:read_file(File),
+    Seq = lists:seq(1, 50),
+    case binary_to_term(Bin) of
+        restart ->
+            _ = [persistent_term:put({?MODULE,I}, {value,I}) ||
+                    I <- Seq],
+            ok = file:write_file(File, term_to_binary(was_restarted)),
+            io:put_chars("1"),
+            init:restart(),
+            receive
+                _ -> ok
+            end;
+        was_restarted ->
+            io:put_chars("2"),
+            ok = file:delete(File),
+            _ = [begin
+                     Key = {?MODULE,I},
+                     {'EXIT',{badarg,_}} = (catch persistent_term:get(Key))
+                 end || I <- Seq],
+            io:put_chars("ok"),
+            init:stop()
+    end.
+
+%% Check that there is the same number of persistents terms before
+%% and after each test case.
+
+chk() ->
+    persistent_term:info().
+
+chk(Chk) ->
+    Chk = persistent_term:info(),
+    Key = {?MODULE,?FUNCTION_NAME},
+    ok = persistent_term:put(Key, {term,Chk}),
+    Term = persistent_term:get(Key),
+    true = persistent_term:erase(Key),
+    chk_not_stuck(Term),
+    ok.
+
+chk_not_stuck(Term) ->
+    %% Hash tables to be deleted are put onto a queue.
+    %% Make sure that the queue isn't stuck by a table with
+    %% a non-zero ref count.
+
+    case erts_debug:size_shared(Term) of
+        0 ->
+            erlang:yield(),
+            chk_not_stuck(Term);
+        _ ->
+            ok
+    end.
diff --git a/erts/preloaded/ebin/erts_internal.beam b/erts/preloaded/ebin/erts_internal.beam
index 15c59de80a..f39c7aa8eb 100644
--- a/erts/preloaded/ebin/erts_internal.beam
+++ b/erts/preloaded/ebin/erts_internal.beam
diff --git a/erts/preloaded/ebin/init.beam b/erts/preloaded/ebin/init.beam
index 858a9dc63e..1e60ef7e88 100644
--- a/erts/preloaded/ebin/init.beam
+++ b/erts/preloaded/ebin/init.beam
diff --git a/erts/preloaded/ebin/persistent_term.beam b/erts/preloaded/ebin/persistent_term.beam
new file mode 100644
index 0000000000..79ef03b9a6
--- /dev/null
+++ b/erts/preloaded/ebin/persistent_term.beam
diff --git a/erts/preloaded/src/Makefile b/erts/preloaded/src/Makefile
index 4333f6643a..e768a8edbc 100644
--- a/erts/preloaded/src/Makefile
+++ b/erts/preloaded/src/Makefile
@@ -47,7 +47,8 @@ PRE_LOADED_ERL_MODULES = \
 	erts_internal \
 	erl_tracer \
 	erts_literal_area_collector \
-	erts_dirty_process_signal_handler
+	erts_dirty_process_signal_handler \
+        persistent_term
 
 PRE_LOADED_BEAM_MODULES = \
 	prim_eval
diff --git a/erts/preloaded/src/erts_internal.erl b/erts/preloaded/src/erts_internal.erl
index 88f47e917b..63b786a473 100644
--- a/erts/preloaded/src/erts_internal.erl
+++ b/erts/preloaded/src/erts_internal.erl
@@ -90,6 +90,8 @@
 
 -export([create_dist_channel/4]).
 
+-export([erase_persistent_terms/0]).
+
 %%
 %% Await result of send to port
 %%
@@ -691,3 +693,7 @@ process_flag(_Pid, _Flag, _Value) ->
                                  
 create_dist_channel(_Node, _DistCtrlr, _Flags, _Ver) ->
     erlang:nif_error(undefined).
+
+-spec erase_persistent_terms() -> 'ok'.
+erase_persistent_terms() ->
+    erlang:nif_error(undefined).
diff --git a/erts/preloaded/src/init.erl b/erts/preloaded/src/init.erl
index 253fcf7a1f..b4b8b3bf9b 100644
--- a/erts/preloaded/src/init.erl
+++ b/erts/preloaded/src/init.erl
@@ -552,6 +552,7 @@ stop(Reason,State) ->
 do_stop(restart,#state{start = Start, flags = Flags, args = Args}) ->
     %% Make sure we don't have any outstanding messages before doing the restart.
     flush(),
+    erts_internal:erase_persistent_terms(),
     boot(Start,Flags,Args);
 do_stop(reboot,_) ->
     halt();
diff --git a/erts/preloaded/src/persistent_term.erl b/erts/preloaded/src/persistent_term.erl
new file mode 100644
index 0000000000..5d0c266127
--- /dev/null
+++ b/erts/preloaded/src/persistent_term.erl
@@ -0,0 +1,55 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2018. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+-module(persistent_term).
+
+-export([erase/1,get/0,get/1,info/0,put/2]).
+
+-type key() :: term().
+-type value() :: term().
+
+-spec erase(Key) -> Result when
+      Key :: key(),
+      Result :: boolean().
+erase(_Key) ->
+    erlang:nif_error(undef).
+
+-spec get() -> List when
+      List :: [{key(),value()}].
+get() ->
+    erlang:nif_error(undef).
+
+-spec get(Key) -> Value when
+      Key :: key(),
+      Value :: value().
+get(_Key) ->
+    erlang:nif_error(undef).
+
+-spec info() -> Info when
+      Info :: #{'count':=Count,'memory':=Memory},
+      Count :: non_neg_integer(),
+      Memory :: non_neg_integer().
+info() ->
+    erlang:nif_error(undef).
+
+-spec put(Key, Value) -> 'ok' when
+      Key :: key(),
+      Value :: value().
+put(_Key, _Value) ->
+    erlang:nif_error(undef).
diff --git a/lib/observer/src/Makefile b/lib/observer/src/Makefile
index ff2bcbdb99..f9f239db37 100644
--- a/lib/observer/src/Makefile
+++ b/lib/observer/src/Makefile
@@ -50,6 +50,7 @@ MODULES= \
 	cdv_mem_cb \
 	cdv_mod_cb \
 	cdv_multi_wx \
+	cdv_persistent_cb \
 	cdv_port_cb \
 	cdv_proc_cb \
 	cdv_sched_cb \
diff --git a/lib/observer/src/cdv_html_wx.erl b/lib/observer/src/cdv_html_wx.erl
index d9efa7fc2f..ffef83227c 100644
--- a/lib/observer/src/cdv_html_wx.erl
+++ b/lib/observer/src/cdv_html_wx.erl
@@ -33,13 +33,17 @@
 	{panel,
 	 app,         %% which tool is the user
 	 expand_table,
-	 expand_wins=[]}).
+         expand_wins=[],
+         delayed_fetch,
+         trunc_warn=[]}).
 
 start_link(ParentWin, Info) ->
     wx_object:start_link(?MODULE, [ParentWin, Info], []).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+init([ParentWin, Callback]) when is_atom(Callback) ->
+    init(ParentWin, Callback);
 init([ParentWin, {App, Fun}]) when is_function(Fun) ->
     init([ParentWin, {App, Fun()}]);
 init([ParentWin, {expand,HtmlText,Tab}]) ->
@@ -60,9 +64,29 @@ init(ParentWin, HtmlText, Tab, App) ->
     wx_misc:endBusyCursor(),
     {HtmlWin, #state{panel=HtmlWin,expand_table=Tab,app=App}}.
 
+init(ParentWin, Callback) ->
+    {HtmlWin, State} = init(ParentWin, "", undefined, cdv),
+    {HtmlWin, State#state{delayed_fetch=Callback}}.
+
 %%%%%%%%%%%%%%%%%%%%%%% Callbacks %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+handle_info(active, #state{panel=HtmlWin,delayed_fetch=Callback}=State)
+  when Callback=/=undefined ->
+    observer_lib:display_progress_dialog(HtmlWin,
+                                         "Crashdump Viewer",
+                                         "Reading data"),
+    {{expand,HtmlText,Tab},TW} = Callback:get_info(),
+    observer_lib:sync_destroy_progress_dialog(),
+    wx_misc:beginBusyCursor(),
+    wxHtmlWindow:setPage(HtmlWin,HtmlText),
+    cdv_wx:set_status(TW),
+    wx_misc:endBusyCursor(),
+    {noreply, State#state{expand_table=Tab,
+                          delayed_fetch=undefined,
+                          trunc_warn=TW}};
+
 handle_info(active, State) ->
+    cdv_wx:set_status(State#state.trunc_warn),
     {noreply, State};
 
 handle_info(Info, State) ->
diff --git a/lib/observer/src/cdv_persistent_cb.erl b/lib/observer/src/cdv_persistent_cb.erl
new file mode 100644
index 0000000000..d5da18f7fc
--- /dev/null
+++ b/lib/observer/src/cdv_persistent_cb.erl
@@ -0,0 +1,32 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2018. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+
+-module(cdv_persistent_cb).
+
+-export([get_info/0]).
+
+-include_lib("wx/include/wx.hrl").
+
+get_info() ->
+    Tab = ets:new(pt_expand,[set,public]),
+    {ok,PT,TW} = crashdump_viewer:persistent_terms(),
+    {{expand,
+      observer_html_lib:expandable_term("Persistent Terms",PT,Tab),
+      Tab},
+     TW}.
diff --git a/lib/observer/src/cdv_wx.erl b/lib/observer/src/cdv_wx.erl
index 78a897111c..1e9cef8952 100644
--- a/lib/observer/src/cdv_wx.erl
+++ b/lib/observer/src/cdv_wx.erl
@@ -51,6 +51,7 @@
 -define(DIST_STR,  "Nodes").
 -define(MOD_STR,   "Modules").
 -define(MEM_STR,   "Memory").
+-define(PERSISTENT_STR, "Persistent Terms").
 -define(INT_STR,   "Internal Tables").
 
 %% Records
@@ -74,6 +75,7 @@
 	 dist_panel,
 	 mod_panel,
 	 mem_panel,
+         persistent_panel,
 	 int_panel,
 	 active_tab
 	}).
@@ -193,6 +195,10 @@ setup(#state{frame=Frame, notebook=Notebook}=State) ->
     %% Memory Panel
     MemPanel = add_page(Notebook, ?MEM_STR, cdv_multi_wx, cdv_mem_cb),
 
+    %% Persistent Terms Panel
+    PersistentPanel = add_page(Notebook, ?PERSISTENT_STR,
+                               cdv_html_wx, cdv_persistent_cb),
+
     %% Memory Panel
     IntPanel = add_page(Notebook, ?INT_STR, cdv_multi_wx, cdv_int_tab_cb),
 
@@ -215,6 +221,7 @@ setup(#state{frame=Frame, notebook=Notebook}=State) ->
 			dist_panel = DistPanel,
 			mod_panel = ModPanel,
 			mem_panel = MemPanel,
+                        persistent_panel = PersistentPanel,
 			int_panel = IntPanel,
 			active_tab = GenPid
 		       }}.
@@ -250,6 +257,7 @@ handle_event(#wx{id = ?wxID_OPEN,
 			  State#state.dist_panel,
 			  State#state.mod_panel,
 			  State#state.mem_panel,
+			  State#state.persistent_panel,
 			  State#state.int_panel],
 		_ = [wx_object:call(Panel,new_dump) || Panel<-Panels],
 		wxNotebook:setSelection(State#state.notebook,0),
@@ -343,8 +351,8 @@ check_page_title(Notebook) ->
 get_active_pid(#state{notebook=Notebook, gen_panel=Gen, pro_panel=Pro,
 		      port_panel=Ports, ets_panel=Ets, timer_panel=Timers,
 		      fun_panel=Funs, atom_panel=Atoms, dist_panel=Dist,
-		      mod_panel=Mods, mem_panel=Mem, int_panel=Int,
-		      sched_panel=Sched
+		      mod_panel=Mods, mem_panel=Mem, persistent_panel=Persistent,
+                      int_panel=Int, sched_panel=Sched
 		     }) ->
     Panel = case check_page_title(Notebook) of
 		?GEN_STR -> Gen;
@@ -358,6 +366,7 @@ get_active_pid(#state{notebook=Notebook, gen_panel=Gen, pro_panel=Pro,
 		?DIST_STR -> Dist;
 		?MOD_STR -> Mods;
 		?MEM_STR -> Mem;
+		?PERSISTENT_STR -> Persistent;
 		?INT_STR -> Int
 	    end,
     wx_object:get_pid(Panel).
@@ -365,7 +374,7 @@ get_active_pid(#state{notebook=Notebook, gen_panel=Gen, pro_panel=Pro,
 pid2panel(Pid, #state{gen_panel=Gen, pro_panel=Pro, port_panel=Ports,
 		      ets_panel=Ets, timer_panel=Timers, fun_panel=Funs,
 		      atom_panel=Atoms, dist_panel=Dist, mod_panel=Mods,
-		      mem_panel=Mem, int_panel=Int}) ->
+		      mem_panel=Mem, persistent_panel=Persistent, int_panel=Int}) ->
     case Pid of
 	Gen -> ?GEN_STR;
 	Pro -> ?PRO_STR;
@@ -377,6 +386,7 @@ pid2panel(Pid, #state{gen_panel=Gen, pro_panel=Pro, port_panel=Ports,
 	Dist -> ?DIST_STR;
 	Mods -> ?MOD_STR;
 	Mem -> ?MEM_STR;
+        ?PERSISTENT_STR -> Persistent;
 	Int -> ?INT_STR;
 	_ -> "unknown"
     end.
diff --git a/lib/observer/src/crashdump_viewer.erl b/lib/observer/src/crashdump_viewer.erl
index 276b209ce5..0627c15b1c 100644
--- a/lib/observer/src/crashdump_viewer.erl
+++ b/lib/observer/src/crashdump_viewer.erl
@@ -74,6 +74,7 @@
 	 loaded_modules/0,
 	 loaded_mod_details/1,
 	 memory/0,
+         persistent_terms/0,
 	 allocated_areas/0,
 	 allocator_info/0,
 	 hash_tables/0,
@@ -139,6 +140,7 @@
 -define(node,node).
 -define(not_connected,not_connected).
 -define(old_instr_data,old_instr_data).
+-define(persistent_terms,persistent_terms).
 -define(port,port).
 -define(proc,proc).
 -define(proc_dictionary,proc_dictionary).
@@ -293,6 +295,8 @@ loaded_mod_details(Mod) ->
     call({loaded_mod_details,Mod}).
 memory() ->
     call(memory).
+persistent_terms() ->
+    call(persistent_terms).
 allocated_areas() ->
     call(allocated_areas).
 allocator_info() ->
@@ -471,6 +475,11 @@ handle_call(memory,_From,State=#state{file=File}) ->
     Memory=memory(File),
     TW = truncated_warning([?memory]),
     {reply,{ok,Memory,TW},State};
+handle_call(persistent_terms,_From,State=#state{file=File,dump_vsn=DumpVsn}) ->
+    TW = truncated_warning([?persistent_terms,?literals]),
+    DecodeOpts = get_decode_opts(DumpVsn),
+    Terms = persistent_terms(File, DecodeOpts),
+    {reply,{ok,Terms,TW},State};
 handle_call(allocated_areas,_From,State=#state{file=File}) ->
     AllocatedAreas=allocated_areas(File),
     TW = truncated_warning([?allocated_areas]),
@@ -1444,15 +1453,7 @@ maybe_other_node2(Channel) ->
 expand_memory(Fd,Pid,DumpVsn) ->
     DecodeOpts = get_decode_opts(DumpVsn),
     put(fd,Fd),
-    Dict0 = case get(?literals) of
-                undefined ->
-                    Literals = read_literals(Fd,DecodeOpts),
-                    put(?literals,Literals),
-                    put(fd,Fd),
-                    Literals;
-                Literals ->
-                    Literals
-            end,
+    Dict0 = get_literals(Fd,DecodeOpts),
     Dict = read_heap(Fd,Pid,DecodeOpts,Dict0),
     Expanded = {read_stack_dump(Fd,Pid,DecodeOpts,Dict),
 		read_messages(Fd,Pid,DecodeOpts,Dict),
@@ -1468,6 +1469,18 @@ expand_memory(Fd,Pid,DumpVsn) ->
         end,
     {Expanded,IncompleteWarning}.
 
+get_literals(Fd,DecodeOpts) ->
+    case get(?literals) of
+        undefined ->
+            OldFd = put(fd,Fd),
+            Literals = read_literals(Fd,DecodeOpts),
+            put(fd,OldFd),
+            put(?literals,Literals),
+            Literals;
+        Literals ->
+            Literals
+    end.
+
 read_literals(Fd,DecodeOpts) ->
     case lookup_index(?literals,[]) of
 	[{_,Start}] ->
@@ -2203,6 +2216,56 @@ get_atom(Atom) when is_binary(Atom) ->
     {Atom,nq}. % not quoted
 
 %%-----------------------------------------------------------------
+%% Page with list of all persistent terms
+persistent_terms(File, DecodeOpts) ->
+    case lookup_index(?persistent_terms) of
+	[{_Id,Start}] ->
+	    Fd = open(File),
+	    pos_bof(Fd,Start),
+	    Terms = get_persistent_terms(Fd),
+            Dict = get_literals(Fd,DecodeOpts),
+            parse_persistent_terms(Terms,DecodeOpts,Dict);
+	_ ->
+	    []
+    end.
+
+parse_persistent_terms([[Name0,Val0]|Terms],DecodeOpts,Dict) ->
+    {Name,_,_} = parse_term(binary_to_list(Name0),DecodeOpts,Dict),
+    {Val,_,_} = parse_term(binary_to_list(Val0),DecodeOpts,Dict),
+    [{Name,Val}|parse_persistent_terms(Terms,DecodeOpts,Dict)];
+parse_persistent_terms([],_,_) -> [].
+
+get_persistent_terms(Fd) ->
+    case get_chunk(Fd) of
+	{ok,Bin} ->
+	    get_persistent_terms(Fd,Bin,[]);
+	eof ->
+	    []
+    end.
+
+
+%% Persistent_Terms are written one per line in the crash dump.
+get_persistent_terms(Fd,Bin,PersistentTerms) ->
+    Bins = binary:split(Bin,<<"\n">>,[global]),
+    get_persistent_terms1(Fd,Bins,PersistentTerms).
+
+get_persistent_terms1(_Fd,[<<"=",_/binary>>|_],PersistentTerms) ->
+    PersistentTerms;
+get_persistent_terms1(Fd,[LastBin],PersistentTerms) ->
+    case get_chunk(Fd) of
+	{ok,Bin0} ->
+	    get_persistent_terms(Fd,<<LastBin/binary,Bin0/binary>>,PersistentTerms);
+	eof ->
+	    [get_persistent_term(LastBin)|PersistentTerms]
+    end;
+get_persistent_terms1(Fd,[Bin|Bins],Persistent_Terms) ->
+    get_persistent_terms1(Fd,Bins,[get_persistent_term(Bin)|Persistent_Terms]).
+
+get_persistent_term(Bin) ->
+    binary:split(Bin,<<"|">>).
+
+
+%%-----------------------------------------------------------------
 %% Page with memory information
 memory(File) ->
     case lookup_index(?memory) of
@@ -3192,6 +3255,7 @@ tag_to_atom("literals") -> ?literals;
 tag_to_atom("loaded_modules") -> ?loaded_modules;
 tag_to_atom("memory") -> ?memory;
 tag_to_atom("mod") -> ?mod;
+tag_to_atom("persistent_terms") -> ?persistent_terms;
 tag_to_atom("no_distribution") -> ?no_distribution;
 tag_to_atom("node") -> ?node;
 tag_to_atom("not_connected") -> ?not_connected;
diff --git a/lib/observer/src/observer.app.src b/lib/observer/src/observer.app.src
index d73293a5f9..d48b846ad2 100644
--- a/lib/observer/src/observer.app.src
+++ b/lib/observer/src/observer.app.src
@@ -34,6 +34,7 @@
 	       cdv_mem_cb,
 	       cdv_mod_cb,
 	       cdv_multi_wx,
+               cdv_persistent_cb,
 	       cdv_port_cb,
 	       cdv_proc_cb,
 	       cdv_table_wx,
diff --git a/lib/observer/src/observer_html_lib.erl b/lib/observer/src/observer_html_lib.erl
index 0c4e32af49..c67fa28c6d 100644
--- a/lib/observer/src/observer_html_lib.erl
+++ b/lib/observer/src/observer_html_lib.erl
@@ -62,7 +62,8 @@ expandable_term_body(Heading,[],_Tab) ->
 	 "Dictionary" -> "No dictionary was found";
 	 "ProcState"  -> "Information could not be retrieved,"
 			     " system messages may not be handled by this process.";
-         "SaslLog"    -> "No log entry was found"
+         "SaslLog"    -> "No log entry was found";
+         "Persistent Terms" -> "No persistent terms were found"
      end];
 expandable_term_body(Heading,Expanded,Tab) ->
     Attr = "BORDER=0 CELLPADDING=0 CELLSPACING=1 WIDTH=100%",
diff --git a/lib/observer/test/crashdump_helper.erl b/lib/observer/test/crashdump_helper.erl
index d8f4e046ae..576d112154 100644
--- a/lib/observer/test/crashdump_helper.erl
+++ b/lib/observer/test/crashdump_helper.erl
@@ -21,7 +21,9 @@
 -module(crashdump_helper).
 -export([n1_proc/2,remote_proc/2,
          dump_maps/0,create_maps/0,
-         create_binaries/0,create_sub_binaries/1]).
+         create_binaries/0,create_sub_binaries/1,
+         dump_persistent_terms/0,
+         create_persistent_terms/0]).
 -compile(r18).
 -include_lib("common_test/include/ct.hrl").
 
@@ -162,3 +164,27 @@ literal_map() ->
     %% Adress1, then the map at Address2.
 
     #{"one"=>1,"two"=>2,"three"=>3,"four"=>4}.
+
+%%%
+%%% Test dumping of persistent terms (from OTP 21.2).
+%%%
+
+dump_persistent_terms() ->
+    Parent = self(),
+    F = fun() ->
+                register(aaaaaaaa_persistent_terms, self()),
+                put(pts, create_persistent_terms()),
+                Parent ! {self(),done},
+                receive _ -> ok end
+        end,
+    Pid = spawn_link(F),
+    receive
+        {Pid,done} ->
+            {ok,Pid}
+    end.
+
+create_persistent_terms() ->
+    persistent_term:put({?MODULE,first}, {pid,42.0}),
+    persistent_term:put({?MODULE,second}, [1,2,3]),
+    persistent_term:get().
+
diff --git a/lib/observer/test/crashdump_viewer_SUITE.erl b/lib/observer/test/crashdump_viewer_SUITE.erl
index 864454cdff..ed53c46a0d 100644
--- a/lib/observer/test/crashdump_viewer_SUITE.erl
+++ b/lib/observer/test/crashdump_viewer_SUITE.erl
@@ -345,6 +345,7 @@ browse_file(File) ->
     {ok,_AllocINfo,_AllocInfoTW} = crashdump_viewer:allocator_info(),
     {ok,_HashTabs,_HashTabsTW} = crashdump_viewer:hash_tables(),
     {ok,_IndexTabs,_IndexTabsTW} = crashdump_viewer:index_tables(),
+    {ok,_PTs,_PTsTW} = crashdump_viewer:persistent_terms(),
 
     io:format("  info read",[]),
 
@@ -595,6 +596,23 @@ special(File,Procs) ->
             Maps = proplists:get_value(maps,Dict),
             io:format("  maps ok",[]),
             ok;
+        ".persistent_terms" ->
+	    %% I registered a process as aaaaaaaa_persistent_term in
+	    %% the dump to make sure it will be the first in the list
+	    %% when sorted on names.
+	    [#proc{pid=Pid0,name=Name}|_Rest] = lists:keysort(#proc.name,Procs),
+            "aaaaaaaa_persistent_terms" = Name,
+	    Pid = pid_to_list(Pid0),
+	    {ok,ProcDetails=#proc{},[]} = crashdump_viewer:proc_details(Pid),
+	    io:format("  process details ok",[]),
+
+	    #proc{dict=Dict} = ProcDetails,
+            %% io:format("~p\n", [Dict]),
+            Pts1 = crashdump_helper:create_persistent_terms(),
+            Pts2 = proplists:get_value(pts,Dict),
+            true = lists:sort(Pts1) =:= lists:sort(Pts2),
+            io:format("  persistent terms ok",[]),
+            ok;
 	_ ->
 	    ok
     end,
@@ -679,9 +697,11 @@ do_create_dumps(DataDir,Rel) ->
             CD5 = dump_with_size_limit_reached(DataDir,Rel,"trunc_bytes"),
             CD6 = dump_with_unicode_atoms(DataDir,Rel,"unicode"),
             CD7 = dump_with_maps(DataDir,Rel,"maps"),
+            CD8 = dump_with_persistent_terms(DataDir,Rel,"persistent_terms"),
             TruncDumpMod = truncate_dump_mod(CD1),
             TruncatedDumpsBinary = truncate_dump_binary(CD1),
-	    {[CD1,CD2,CD3,CD4,CD5,CD6,CD7,TruncDumpMod|TruncatedDumpsBinary],
+	    {[CD1,CD2,CD3,CD4,CD5,CD6,CD7,CD8,
+              TruncDumpMod|TruncatedDumpsBinary],
              DosDump};
 	_ ->
 	    {[CD1,CD2], DosDump}
@@ -850,6 +870,16 @@ dump_with_maps(DataDir,Rel,DumpName) ->
     ?t:stop_node(n1),
     CD.
 
+dump_with_persistent_terms(DataDir,Rel,DumpName) ->
+    Opt = rel_opt(Rel),
+    Pz = "-pz \"" ++ filename:dirname(code:which(?MODULE)) ++ "\"",
+    PzOpt = [{args,Pz}],
+    {ok,N1} = ?t:start_node(n1,peer,Opt ++ PzOpt),
+    {ok,_Pid} = rpc:call(N1,crashdump_helper,dump_persistent_terms,[]),
+    CD = dump(N1,DataDir,Rel,DumpName),
+    ?t:stop_node(n1),
+    CD.
+
 dump(Node,DataDir,Rel,DumpName) ->
     Crashdump = filename:join(DataDir, dump_prefix(Rel)++DumpName),
     rpc:call(Node,os,putenv,["ERL_CRASH_DUMP",Crashdump]),
diff --git a/lib/sasl/src/systools_make.erl b/lib/sasl/src/systools_make.erl
index 6916107623..983df58ef7 100644
--- a/lib/sasl/src/systools_make.erl
+++ b/lib/sasl/src/systools_make.erl
@@ -1565,7 +1565,7 @@ preloaded() ->
     [erl_prim_loader,erl_tracer,erlang,
      erts_code_purger,erts_dirty_process_signal_handler,
      erts_internal,erts_literal_area_collector,
-     init,otp_ring0,prim_buffer,prim_eval,prim_file,
+     init,otp_ring0,persistent_term,prim_buffer,prim_eval,prim_file,
      prim_inet,prim_zip,zlib].
 
 %%______________________________________________________________________