Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 24 Aug 2015 14:10:10 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [patch -mm] mm, oom: add global access to memory reserves on livelock |
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On Fri, 21 Aug 2015, Tetsuo Handa wrote:
> Why can't we think about choosing more OOM victims instead of granting access > to memory reserves? >
We have no indication of which thread is holding a mutex that would need to be killed, so we'd be randomly killing processes waiting for forward progress. A worst-case scenario would be the thread is OOM_DISABLE and we kill every process on the system needlessly. This problem obviously occurs often enough that killing all userspace isnt going to be a viable solution.
> Also, SysRq might not be usable under OOM because workqueues can get stuck. > The panic_on_oom_timeout was first proposed using a workqueue but was > updated to use a timer because there is no guarantee that workqueues work > as expected under OOM. >
I don't know anything about a panic_on_oom_timeout, but panicking would only be a reasonable action if memory reserves were fully depleted. That could easily be dealt with in the page allocator so there's no timeout involved.
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