Messages in this thread | | | From | Joel Fernandes <> | Date | Thu, 1 Nov 2018 16:33:47 -0700 | Subject | Re: [diamon-discuss] [RELEASE] LTTng-modules 2.9.11, 2.10.8, 2.11.0-rc2 (Linux kernel tracer) |
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On Thu, Nov 1, 2018 at 3:56 PM Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote: > > Hi, > > This is a set of bugfix releases of the LTTng modules kernel tracer. > It covers the three currently active lttng-modules branches: the > 2.9 and 2.10 stable branches, as well as the 2.11 branch in release > candidate cycle. > > Those releases add support for kernel 4.19. > > One important improvement is to prevent allocation of buffers larger > than the available memory, which can cause the OOM killer to trigger. > Even if the OOM killer end up having to trigger, the current OOM kill > target is set to the current thread while allocating buffers.
This is interesting. Me and Steve were looking at exactly this issue with the ftrace ring buffer a few months ago. Turns out that even setting the OOM kill target may not be enough to prevent all OOMs. I don't remember the reason why not, I'll have to dig out those threads but that's what the -mm folks said at the time. I did remember vaguely that I tested it and the kill target doesn't always get killed.. its possible that something *other* parallel allocation can be victimized AFAIR, even though the culprit is the kill target.
- Joel
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