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-rw-r--r--erts/doc/src/Makefile2
-rw-r--r--erts/doc/src/persistent_term.xml290
-rw-r--r--erts/doc/src/ref_man.xml1
-rw-r--r--erts/doc/src/specs.xml1
-rw-r--r--erts/emulator/Makefile.in32
-rw-r--r--erts/emulator/beam/atom.names3
-rw-r--r--erts/emulator/beam/bif.tab12
-rw-r--r--erts/emulator/beam/erl_alloc.types3
-rw-r--r--erts/emulator/beam/erl_bif_persistent.c983
-rw-r--r--erts/emulator/beam/erl_init.c1
-rw-r--r--erts/emulator/beam/erl_lock_check.c2
-rw-r--r--erts/emulator/beam/erl_process_dump.c40
-rw-r--r--erts/emulator/beam/global.h7
-rw-r--r--erts/emulator/test/Makefile1
-rw-r--r--erts/emulator/test/persistent_term_SUITE.erl614
-rw-r--r--erts/preloaded/ebin/erts_internal.beambin16676 -> 16804 bytes
-rw-r--r--erts/preloaded/ebin/init.beambin51428 -> 51500 bytes
-rw-r--r--erts/preloaded/ebin/persistent_term.beambin0 -> 1652 bytes
-rw-r--r--erts/preloaded/src/Makefile3
-rw-r--r--erts/preloaded/src/erts_internal.erl6
-rw-r--r--erts/preloaded/src/init.erl1
-rw-r--r--erts/preloaded/src/persistent_term.erl55
-rw-r--r--lib/sasl/src/systools_make.erl2
23 files changed, 2040 insertions, 19 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/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/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index 5409b89bab..86d93d94c4 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -277,6 +277,9 @@ type SETUP_CONN_ARG SHORT_LIVED PROCESSES setup_connection_argument
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 54d309ff2f..0631404599 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1242,6 +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
Binary files differ
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
Binary files differ
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
Binary files differ
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/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].
%%______________________________________________________________________