[erlang-questions] strange VM hangup with mremap() cycle (R14B04)

Valentin Nechayev <>
Fri Apr 27 17:57:26 CEST 2012


Hi,
as seen on <strike>national TV</strike> my monitor just now: an Erlang
VM in out system has hung up, with one thread active and all other
sleeping. The active thread strace shows:

19:45:06.215838 mremap(0x7f47ca48b000, 190615552, 190619648, MREMAP_MAYMOVE) = 0x7f47e5217000
19:45:06.344998 mremap(0x7f47e5217000, 190619648, 190623744, MREMAP_MAYMOVE) = 0x7f47ca489000
19:45:06.428110 mremap(0x7f47ca489000, 190623744, 190627840, MREMAP_MAYMOVE) = 0x7f47e5215000

& so on & so forth, with rate ~5 calls per second.
VM memory grows approx. 2MB/minute.

No system calls except remap() are seen for a long time. There is no way
to connect to the node, and it has cluster connections lost, but epmd
still remembers it. The beam binary is stripped so I don't expect a help
from gdb.

Previously, it worked ~16 minutes without any problem.

Is this known problem?

Does heart(3) help against such problems? I can't find details of its
action to reboot the node if watchdog is timed out.


-netch-



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