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authorLukas Larsson <[email protected]>2016-04-21 18:36:45 +0200
committerLukas Larsson <[email protected]>2016-05-10 08:33:03 +0200
commite146a3eec5a2d384260aa8829777c89eaab09cbd (patch)
tree474b3ea6372918215f2b810f0f694d02684d8b58 /lib/stdlib/doc/src/proc_lib.xml
parent5ca152a5ccca92e354188f7b696ca5b9f6b92806 (diff)
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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}
Diffstat (limited to 'lib/stdlib/doc/src/proc_lib.xml')
-rw-r--r--lib/stdlib/doc/src/proc_lib.xml7
1 files changed, 7 insertions, 0 deletions
diff --git a/lib/stdlib/doc/src/proc_lib.xml b/lib/stdlib/doc/src/proc_lib.xml
index 245580b1ba..f02b1f0651 100644
--- a/lib/stdlib/doc/src/proc_lib.xml
+++ b/lib/stdlib/doc/src/proc_lib.xml
@@ -73,6 +73,13 @@
<name name="priority_level"/>
</datatype>
<datatype>
+ <name name="max_heap_size"/>
+ <desc>
+ <p>See <seealso marker="erts:erlang#process_flag_max_heap_size">
+ erlang:process_flag(max_heap_size, MaxHeapSize)</seealso>.</p>
+ </desc>
+ </datatype>
+ <datatype>
<name name="dict_or_pid"/>
</datatype>
</datatypes>