erts: Implement max_heap_size process flag

The max_heap_size process flag can be used to limit the
growth of a process heap by killing it before it becomes
too large to handle. It is possible to set the maximum
using the `erl +hmax` option, `system_flag(max_heap_size, ...)`,
`spawn_opt(Fun, [{max_heap_size, ...}])` and
`process_flag(max_heap_size, ...)`.

It is possible to configure the behaviour of the process
when the maximum heap size is reached. The process may be
sent an untrappable exit signal with reason kill and/or
send an error_logger message with details on the process
state. A new trace event called gc_max_heap_size is
also triggered for the garbage_collection trace flag
when the heap grows larger than the configured size.

If kill and error_logger are disabled, it is still
possible to see that the maximum has been reached by
doing garbage collection tracing on the process.

The heap size is defined as the sum of the heap memory
that the process is currently using. This includes
all generational heaps, the stack, any messages that
are considered to be part of the heap and any extra
memory the garbage collector may need during collection.

In the current implementation this means that when a process
is set using on_heap message queue data mode, the messages
that are in the internal message queue are counted towards
this value. For off_heap, only matched messages count towards
the size of the heap. For mixed, it depends on race conditions
within the VM whether a message is part of the heap or not.

Below is an example run of the new behaviour:

Eshell V8.0  (abort with ^G)
1> f(P),P = spawn_opt(fun() -> receive ok -> ok end end, [{max_heap_size, 512}]).
<0.60.0>
2> erlang:trace(P, true, [garbage_collection, procs]).
1
3> [P ! lists:duplicate(M,M) || M <- lists:seq(1,15)],ok.
ok
4>
=ERROR REPORT==== 26-Apr-2016::16:25:10 ===
     Process:          <0.60.0>
     Context:          maximum heap size reached
     Max heap size:    512
     Total heap size:  723
     Kill:             true
     Error Logger:     true
     GC Info:          [{old_heap_block_size,0},
                        {heap_block_size,609},
                        {mbuf_size,145},
                        {recent_size,0},
                        {stack_size,9},
                        {old_heap_size,0},
                        {heap_size,211},
                        {bin_vheap_size,0},
                        {bin_vheap_block_size,46422},
                        {bin_old_vheap_size,0},
                        {bin_old_vheap_block_size,46422}]
flush().
Shell got {trace,<0.60.0>,gc_start,
                 [{old_heap_block_size,0},
                  {heap_block_size,233},
                  {mbuf_size,145},
                  {recent_size,0},
                  {stack_size,9},
                  {old_heap_size,0},
                  {heap_size,211},
                  {bin_vheap_size,0},
                  {bin_vheap_block_size,46422},
                  {bin_old_vheap_size,0},
                  {bin_old_vheap_block_size,46422}]}
Shell got {trace,<0.60.0>,gc_max_heap_size,
                 [{old_heap_block_size,0},
                  {heap_block_size,609},
                  {mbuf_size,145},
                  {recent_size,0},
                  {stack_size,9},
                  {old_heap_size,0},
                  {heap_size,211},
                  {bin_vheap_size,0},
                  {bin_vheap_block_size,46422},
                  {bin_old_vheap_size,0},
                  {bin_old_vheap_block_size,46422}]}
Shell got {trace,<0.60.0>,exit,killed}

1 files changed, 230 insertions, 64 deletions

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index bf30cc7928..3930e5e11d 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -4322,6 +4322,7 @@ os_prompt% </pre>
       </desc>
     </func>
 
+    <marker id="process_flag_min_heap_size"/>
     <func>
       <name name="process_flag" arity="2" clause_i="3"/>
       <fsummary>Sets process flag <c>min_heap_size</c> for the calling process.</fsummary>
@@ -4340,9 +4341,95 @@ os_prompt% </pre>
         <p>Returns the old value of the flag.</p>
       </desc>
     </func>
-    <marker id="process_flag_message_queue_data"/>
+    <marker id="process_flag_max_heap_size"/>
     <func>
       <name name="process_flag" arity="2" clause_i="5"/>
+      <type name="max_heap_size"/>
+      <fsummary>Sets process flag <c>max_heap_size</c> for the calling process.</fsummary>
+      <desc>
+        <p>
+          This flag sets the maximum heap size for the calling process.
+          If <c><anno>MaxHeapSize</anno></c> is an integer, the system default
+          values for <c>kill</c> and <c>error_logger</c> are used.
+          <taglist>
+            <tag><c>size</c></tag>
+            <item>
+              <p>
+                The maximum size in words of the process. If set to zero, the
+                heap size limit is disabled. Badarg will be thrown if the value is
+                smaller than
+                <seealso marker="#process_flag_min_heap_size"><c>min_heap_size</c></seealso>.
+                The size check is only done when a garbage collection is triggered.
+              </p>
+              <p>
+                <c>size</c> is the entire heap of the process when garbage collection
+                is triggered, this includes all generational heaps, the process stack, 
+                any <seealso marker="process_flag_message_queue_data">
+                messages that are considered to be part of the heap</seealso> and any
+                extra memory that the garbage collector needs during collection.
+              </p>
+              <p>
+                <c>size</c> is the same as can be retrieved using
+                <seealso marker="#process_info_total_heap_size">
+                  <c>erlang:process_info(Pid, total_heap_size)</c></seealso>,
+                  or by adding <c>heap_block_size</c>, <c>old_heap_block_size</c>
+                  and <c>mbuf_size</c> from <seealso marker="#process_info_garbage_collection_info">
+                  <c>erlang:process_info(Pid, garbage_collection_info)</c></seealso>.
+              </p>
+            </item>
+            <tag><c>kill</c></tag>
+            <item>
+              <p>
+                When set to <c>true</c> the runtime system will send an
+                untrappable exit signal with reason <c>kill</c> to the process
+                if the maximum heap size is reached. The garbage collection
+                that triggered the <c>kill</c> will not be completed, instead the
+                process will exit as soon as is possible. When set to <c>false</c>
+                no exit signal will be sent to the process, instead it will
+                continue executing.
+              </p>
+              <p>
+                If <c>kill</c> is not defined in the map
+                the system default will be used. The default system default
+                is <c>true</c>. It can be changed by either the erl
+                <seealso marker="erl#+hmaxk">+hmaxk</seealso> option,
+                or <seealso marker="#system_flag_max_heap_size"><c>
+                erlang:system_flag(max_heap_size, MaxHeapSize)</c></seealso>.
+              </p>
+            </item>
+            <tag><c>error_logger</c></tag>
+            <item>
+              <p>
+                When set to <c>true</c> the runtime system will send a
+                message to the current <seealso marker="kernel:error_logger"><c>error_logger</c></seealso>
+                containing details about the process when the maximum
+                heap size is reached. One <c>error_logger</c> report will
+                be sent each time the limit is reached.
+              </p>
+              <p>
+                If <c>error_logger</c> is not defined in the map the system
+                default will be used. The default system default is <c>true</c>.
+                It can be changed by either the erl <seealso marker="erl#+hmaxel">+hmaxel</seealso>
+                option, or <seealso marker="#system_flag_max_heap_size"><c>
+                erlang:system_flag(max_heap_size, MaxHeapSize)</c></seealso>.
+              </p>
+            </item>
+            <p>
+              The heap size of a process is quite hard to predict, especially the
+              amount of memory that is used during the garbage collection. When
+              contemplating using this option, it is recommended to first run
+              it in production with <c>kill</c> set to <c>false</c> and inspect
+              the <c>error_logger</c> reports to see what the normal peak sizes
+              of the processes in the system is and then tune the value
+              accordingly.
+            </p>
+          </taglist>
+        </p>
+      </desc>
+    </func>
+    <marker id="process_flag_message_queue_data"/>
+    <func>
+      <name name="process_flag" arity="2" clause_i="6"/>
       <fsummary>Set process flag <c>message_queue_data</c> for the calling process</fsummary>
       <type name="message_queue_data"/>
       <desc>
@@ -4392,7 +4479,7 @@ os_prompt% </pre>
       </desc>
     </func>
     <func>
-      <name name="process_flag" arity="2" clause_i="6"/>
+      <name name="process_flag" arity="2" clause_i="7"/>
       <fsummary>Sets process flag <c>priority</c> for the calling process.</fsummary>
       <type name="priority_level"/>
       <desc>
@@ -4466,7 +4553,7 @@ os_prompt% </pre>
     </func>
 
     <func>
-      <name name="process_flag" arity="2" clause_i="7"/>
+      <name name="process_flag" arity="2" clause_i="8"/>
       <fsummary>Sets process flag <c>save_calls</c> for the calling process.</fsummary>
       <desc>
         <p><c><anno>N</anno></c> must be an integer in the interval 0..10000.
@@ -4497,7 +4584,7 @@ os_prompt% </pre>
     </func>
 
     <func>
-      <name name="process_flag" arity="2" clause_i="8"/>
+      <name name="process_flag" arity="2" clause_i="9"/>
       <fsummary>Sets process flag <c>sensitive</c> for the calling process.</fsummary>
       <desc>
         <p>Sets or clears flag <c>sensitive</c> for the current process.
@@ -4551,6 +4638,7 @@ os_prompt% </pre>
       <type name="process_info_result_item"/>
       <type name="priority_level"/>
       <type name="stack_item"/>
+      <type name="max_heap_size" />
       <type name="message_queue_data" />
       <desc>
         <p>Returns a list containing <c><anno>InfoTuple</anno></c>s with
@@ -4604,6 +4692,7 @@ os_prompt% </pre>
       <type name="process_info_result_item"/>
       <type name="stack_item"/>
       <type name="priority_level"/>
+      <type name="max_heap_size" />
       <type name="message_queue_data" />
       <desc>
         <p>Returns information about the process identified by
@@ -4696,6 +4785,7 @@ os_prompt% </pre>
 	       The content of <c><anno>GCInfo</anno></c> can be changed without
 	       prior notice.</p>
           </item>
+          <marker id="process_info_garbage_collection_info"/>
           <tag><c>{garbage_collection_info, <anno>GCInfo</anno>}</c></tag>
           <item>
             <p><c><anno>GCInfo</anno></c> is a list containing miscellaneous
@@ -4875,6 +4965,7 @@ os_prompt% </pre>
             total suspend count on <c><anno>Suspendee</anno></c>,
             only the parts contributed by <c><anno>Pid</anno></c>.</p>
           </item>
+          <marker id="process_info_total_heap_size"/>
           <tag><c>{total_heap_size, <anno>Size</anno>}</c></tag>
           <item>
             <p><c><anno>Size</anno></c> is the total size, in words, of all heap
@@ -5569,6 +5660,7 @@ true</pre>
       <name name="spawn_opt" arity="2"/>
       <fsummary>Creates a new process with a fun as entry point.</fsummary>
       <type name="priority_level"/>
+      <type name="max_heap_size" />
       <type name="message_queue_data" />
       <type name="spawn_opt_option" />
       <desc>
@@ -5586,6 +5678,7 @@ true</pre>
       <name name="spawn_opt" arity="3"/>
       <fsummary>Creates a new process with a fun as entry point on a given node.</fsummary>
       <type name="priority_level"/>
+      <type name="max_heap_size" />
       <type name="message_queue_data" />
       <type name="spawn_opt_option" />
       <desc>
@@ -5602,6 +5695,7 @@ true</pre>
       <name name="spawn_opt" arity="4"/>
       <fsummary>Creates a new process with a function as entry point.</fsummary>
       <type name="priority_level"/>
+      <type name="max_heap_size" />
       <type name="message_queue_data" />
       <type name="spawn_opt_option" />
       <desc>
@@ -5705,6 +5799,16 @@ true</pre>
               fine-tuning an application and to measure the execution
               time with various <c><anno>VSize</anno></c> values.</p>
           </item>
+          <tag><c>{max_heap_size, <anno>Size</anno>}</c></tag>
+          <item>
+            <p>Sets the <c>max_heap_size</c> process flag. The default
+            <c>max_heap_size</c> is determined by the
+            <seealso marker="erl#+hmax"><c>+hmax</c></seealso> <c>erl</c>
+	    command line argument. For more information, see the
+	    documentation of
+            <seealso marker="#process_flag_max_heap_size"><c>process_flag(max_heap_size,
+	    <anno>Size</anno>)</c></seealso>.</p>
+          </item>
           <tag><c>{message_queue_data, <anno>MQD</anno>}</c></tag>
           <item>
             <p>Sets the state of the <c>message_queue_data</c> process
@@ -5725,6 +5829,7 @@ true</pre>
       <name name="spawn_opt" arity="5"/>
       <fsummary>Creates a new process with a function as entry point on a given node.</fsummary>
       <type name="priority_level"/>
+      <type name="max_heap_size" />
       <type name="message_queue_data" />
       <type name="spawn_opt_option" />
       <desc>
@@ -6506,8 +6611,25 @@ ok
       </desc>
     </func>
 
+    <marker id="system_flag_max_heap_size"></marker>
     <func>
       <name name="system_flag" arity="2" clause_i="8"/>
+      <type name="max_heap_size"/>
+      <fsummary>Sets system flag <c>max_heap_size</c></fsummary>
+      <desc>
+        <p>
+          Sets the default maximum heap size settings for processes.
+          The size is given in words. The new <c>max_heap_size</c>
+          effects only processes spawned efter the change has been made.
+          <c>max_heap_size</c> can be set for individual processes using
+          <seealso marker="#spawn_opt/4">spawn_opt/N</seealso> or
+          <seealso marker="#process_flag_message_queue_data">process_flag/2</seealso>.</p>
+        <p>Returns the old value of the flag.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="system_flag" arity="2" clause_i="9"/>
       <fsummary>Sets system flag <c>multi_scheduling</c>.</fsummary>
       <desc>
         <p><marker id="system_flag_multi_scheduling"></marker>
@@ -6557,7 +6679,7 @@ ok
     </func>
 
     <func>
-      <name name="system_flag" arity="2" clause_i="9"/>
+      <name name="system_flag" arity="2" clause_i="10"/>
       <fsummary>Sets system flag <c>scheduler_bind_type</c>.</fsummary>
       <type name="scheduler_bind_type"/>
       <desc>
@@ -6675,7 +6797,7 @@ ok
     </func>
 
     <func>
-      <name name="system_flag" arity="2" clause_i="10"/>
+      <name name="system_flag" arity="2" clause_i="11"/>
       <fsummary>Sets system flag <c>scheduler_wall_time</c>.</fsummary>
       <desc><p><marker id="system_flag_scheduler_wall_time"></marker>
       Turns on or off scheduler wall time measurements.</p>
@@ -6685,7 +6807,7 @@ ok
     </func>
 
     <func>
-      <name name="system_flag" arity="2" clause_i="11"/>
+      <name name="system_flag" arity="2" clause_i="12"/>
       <fsummary>Sets system flag <c>schedulers_online</c>.</fsummary>
       <desc>
         <p><marker id="system_flag_schedulers_online"></marker>
@@ -6710,7 +6832,7 @@ ok
     </func>
 
     <func>
-      <name name="system_flag" arity="2" clause_i="12"/>
+      <name name="system_flag" arity="2" clause_i="13"/>
       <fsummary>Sets system flag <c>trace_control_word</c>.</fsummary>
       <desc>
         <p>Sets the value of the node trace control word to
@@ -6724,7 +6846,7 @@ ok
     </func>
 
     <func>
-      <name name="system_flag" arity="2" clause_i="12"/>
+      <name name="system_flag" arity="2" clause_i="14"/>
       <fsummary>Finalize the Time Offset</fsummary>
       <desc>
         <p><marker id="system_flag_time_offset"></marker>
@@ -6991,6 +7113,81 @@ ok
     </func>
 
     <func>
+      <name name="system_info" arity="1" clause_i="27"/>
+      <name name="system_info" arity="1" clause_i="28"/>
+      <name name="system_info" arity="1" clause_i="36"/>
+      <name name="system_info" arity="1" clause_i="37"/>
+      <name name="system_info" arity="1" clause_i="38"/>
+      <name name="system_info" arity="1" clause_i="39"/>
+      <type name="message_queue_data"/>
+      <type name="max_heap_size"/>
+      <fsummary>Information about the default process heap settings.</fsummary>
+      <desc>
+        <taglist>
+          <tag><c>fullsweep_after</c></tag>
+          <item>
+            <p>Returns <c>{fullsweep_after, integer() >= 0}</c>, which is
+              the <c>fullsweep_after</c> garbage collection setting used
+              by default. For more information, see
+              <c>garbage_collection</c> described in the following.</p>
+          </item>
+          <tag><c>garbage_collection</c></tag>
+          <item>
+            <p>Returns a list describing the default garbage collection
+              settings. A process spawned on the local node by a
+              <c>spawn</c> or <c>spawn_link</c> uses these
+              garbage collection settings. The default settings can be
+              changed by using
+              <seealso marker="#system_flag/2">system_flag/2</seealso>.
+              <seealso marker="#spawn_opt/4">spawn_opt/4</seealso>
+              can spawn a process that does not use the default
+              settings.</p>
+          </item>
+          <tag><c>max_heap_size</c></tag>
+          <item>
+	      <p>Returns <c>{max_heap_size, <anno>MaxHeapSize</anno>}</c>,
+              where <c><anno>MaxHeapSize</anno></c> is the current
+              system-wide max heap size settings for spawned processes.
+              This setting can be set using the <c>erl</c> command line
+              flags <seealso marker="erl#+hmax"><c>+hmax</c></seealso>,
+              <seealso marker="erl#+hmaxk"><c>+hmaxk</c></seealso> and
+              <seealso marker="erl#+hmaxel"><c>+hmaxel</c></seealso>. It can
+              also be changed at run-time using
+              <seealso marker="#system_flag_max_heap_size">
+                <c>erlang:system_flag(max_heap_size, MaxHeapSize)</c></seealso>.
+              For more details about the <c>max_heap_size</c> process flag
+              see <seealso marker="#process_flag_max_heap_size">
+                <c>process_flag(max_heap_size, MaxHeapSize)</c></seealso>.
+              </p>
+          </item>
+	  <tag><c>min_heap_size</c></tag>
+          <item>
+	      <p>Returns <c>{min_heap_size, <anno>MinHeapSize</anno>}</c>,
+              where <c><anno>MinHeapSize</anno></c> is the current
+              system-wide minimum heap size for spawned processes.</p>
+          </item>
+          <tag><marker id="system_info_message_queue_data"><c>message_queue_data</c></marker></tag>
+          <item>
+            <p>Returns the default value of the <c>message_queue_data</c>
+	    process flag which is either <c>off_heap</c>, <c>on_heap</c>, or <c>mixed</c>.
+	    This default is set by the <c>erl</c> command line argument
+	    <seealso marker="erl#+hmqd"><c>+hmqd</c></seealso>. For more information on the
+	    <c>message_queue_data</c> process flag, see documentation of
+            <seealso marker="#process_flag_message_queue_data"><c>process_flag(message_queue_data,
+	    MQD)</c></seealso>.</p>
+          </item>
+	  <tag><c>min_bin_vheap_size</c></tag>
+          <item>
+	      <p>Returns <c>{min_bin_vheap_size,
+              <anno>MinBinVHeapSize</anno>}</c>, where
+              <c><anno>MinBinVHeapSize</anno></c> is the current system-wide
+	      minimum binary virtual heap size for spawned processes.</p>
+          </item>
+        </taglist>
+      </desc>
+    </func>
+
+    <func>
       <name name="system_info" arity="1" clause_i="6"/>
       <name name="system_info" arity="1" clause_i="7"/>
       <name name="system_info" arity="1" clause_i="8"/>
@@ -7010,8 +7207,6 @@ ok
       <name name="system_info" arity="1" clause_i="24"/>
       <name name="system_info" arity="1" clause_i="25"/>
       <name name="system_info" arity="1" clause_i="26"/>
-      <name name="system_info" arity="1" clause_i="27"/>
-      <name name="system_info" arity="1" clause_i="28"/>
       <name name="system_info" arity="1" clause_i="29"/>
       <name name="system_info" arity="1" clause_i="30"/>
       <name name="system_info" arity="1" clause_i="31"/>
@@ -7019,10 +7214,6 @@ ok
       <name name="system_info" arity="1" clause_i="33"/>
       <name name="system_info" arity="1" clause_i="34"/>
       <name name="system_info" arity="1" clause_i="35"/>
-      <name name="system_info" arity="1" clause_i="36"/>
-      <name name="system_info" arity="1" clause_i="37"/>
-      <name name="system_info" arity="1" clause_i="38"/>
-      <name name="system_info" arity="1" clause_i="39"/>
       <name name="system_info" arity="1" clause_i="40"/>
       <name name="system_info" arity="1" clause_i="41"/>
       <name name="system_info" arity="1" clause_i="42"/>
@@ -7052,6 +7243,7 @@ ok
       <name name="system_info" arity="1" clause_i="66"/>
       <name name="system_info" arity="1" clause_i="67"/>
       <name name="system_info" arity="1" clause_i="68"/>
+      <name name="system_info" arity="1" clause_i="69"/>
       <fsummary>Information about the system.</fsummary>
       <desc>
         <p>Returns various information about the current system
@@ -7288,25 +7480,6 @@ ok
               <c>ERL_MAX_ETS_TABLES</c> before starting the Erlang
               runtime system.</p>
           </item>
-          <tag><c>fullsweep_after</c></tag>
-          <item>
-            <p>Returns <c>{fullsweep_after, integer() >= 0}</c>, which is
-              the <c>fullsweep_after</c> garbage collection setting used
-              by default. For more information, see
-              <c>garbage_collection</c> described in the following.</p>
-          </item>
-          <tag><c>garbage_collection</c></tag>
-          <item>
-            <p>Returns a list describing the default garbage collection
-              settings. A process spawned on the local node by a
-              <c>spawn</c> or <c>spawn_link</c> uses these
-              garbage collection settings. The default settings can be
-              changed by using
-              <seealso marker="#system_flag/2">system_flag/2</seealso>.
-              <seealso marker="#spawn_opt/4">spawn_opt/4</seealso>
-              can spawn a process that does not use the default
-              settings.</p>
-          </item>
           <tag><c>heap_sizes</c></tag>
           <item>
             <p>Returns a list of integers representing valid heap sizes 
@@ -7381,29 +7554,6 @@ ok
           <item>
             <p>Returns a string containing the Erlang machine name.</p>
           </item>
-	  <tag><c>min_heap_size</c></tag>
-          <item>
-	      <p>Returns <c>{min_heap_size, <anno>MinHeapSize</anno>}</c>,
-              where <c><anno>MinHeapSize</anno></c> is the current
-              system-wide minimum heap size for spawned processes.</p>
-          </item>
-          <tag><marker id="system_info_message_queue_data"><c>message_queue_data</c></marker></tag>
-          <item>
-            <p>Returns the default value of the <c>message_queue_data</c>
-	    process flag which is either <c>off_heap</c>, <c>on_heap</c>, or <c>mixed</c>.
-	    This default is set by the <c>erl</c> command line argument
-	    <seealso marker="erl#+hmqd"><c>+hmqd</c></seealso>. For more information on the
-	    <c>message_queue_data</c> process flag, see documentation of
-            <seealso marker="#process_flag_message_queue_data"><c>process_flag(message_queue_data,
-	    MQD)</c></seealso>.</p>
-          </item>
-	  <tag><c>min_bin_vheap_size</c></tag>
-          <item>
-	      <p>Returns <c>{min_bin_vheap_size,
-              <anno>MinBinVHeapSize</anno>}</c>, where
-              <c><anno>MinBinVHeapSize</anno></c> is the current system-wide
-	      minimum binary virtual heap size for spawned processes.</p>
-          </item>
           <tag><c>modified_timing_level</c></tag>
           <item>
             <p>Returns the modified timing-level (an integer) if
@@ -8028,12 +8178,13 @@ ok
               <c>GcPid</c> and <c>Info</c>
               are the same as for <c>long_gc</c> earlier, except that
               the tuple tagged with <c>timeout</c> is not present.</p>
-            <p>As of <c>ERTS</c> 5.6, the monitor message is sent
-              if the sum of the sizes of all memory blocks allocated
-              for all heap generations is equal to or higher than <c>Size</c>.
-              Previously the monitor message was sent if the memory block
-              allocated for the youngest generation was equal to or higher
-              than <c>Size</c>.</p>
+            <p>The monitor message is sent if the sum of the sizes of
+              all memory blocks allocated for all heap generations after
+              a garbage collection is equal to or higher than <c>Size</c>.</p>
+            <p>When a process is killed by <seealso marker="#process_flag_max_heap_size">
+              <c>max_heap_size</c></seealso>, it is killed before the
+              garbage collection is complete and thus no large heap message
+              will be sent.</p>
           </item>
           <tag><c>busy_port</c></tag>
           <item>
@@ -8560,7 +8711,9 @@ timestamp() ->
           <tag><c>garbage_collection</c></tag>
           <item>
             <p>Traces garbage collections of processes.</p>
-            <p>Message tags: <c><seealso marker="#trace_3_trace_messages_gc_minor_start">gc_minor_start</seealso></c> and <c><seealso marker="#trace_3_trace_messages_gc_minor_end">gc_minor_end</seealso></c>.</p>
+            <p>Message tags: <c><seealso marker="#trace_3_trace_messages_gc_minor_start">gc_minor_start</seealso></c>,
+            <c><seealso marker="#trace_3_trace_messages_gc_max_heap_size">gc_max_heap_size</seealso></c> and
+	    <c><seealso marker="#trace_3_trace_messages_gc_minor_end">gc_minor_end</seealso></c>.</p>
           </item>
           <tag><c>timestamp</c></tag>
           <item>
@@ -8929,6 +9082,19 @@ timestamp() ->
             <p>All sizes are in words.</p>
           </item>
           <tag>
+            <marker id="trace_3_trace_messages_gc_max_heap_size"></marker>
+            <c>{trace, Pid, gc_max_heap_size, Info}</c>
+          </tag>
+          <item>
+            <p>
+              Sent when the <seealso marker="#process_flag_max_heap_size"><c>max_heap_size</c></seealso>
+              is reached during garbage collection. <c>Info</c> contains the
+              same kind of list as in message <c>gc_start</c>,
+              but the sizes reflect the sizes that triggered max_heap_size to
+              be reached.
+            </p>
+          </item>
+          <tag>
             <marker id="trace_3_trace_messages_gc_minor_end"></marker>
             <c>{trace, Pid, gc_minor_end, Info}</c>
           </tag>