Re: VM: add would_have_oomkilled sysctl

From: David Rientjes
Date: Fri Aug 26 2011 - 14:21:34 EST


On Fri, 26 Aug 2011, Dave Jones wrote:

> At various times in the past, we've had reports where users have been
> convinced that the oomkiller was too heavy handed. I added this sysctl
> mostly as a knob for them to see that the kernel really doesn't do much better
> without killing something.
>

The page allocator expects that the oom killer will kill something to free
memory so it takes a temporary timeout and then retries the allocation
indefinitely. We never oom kill unless we are going to retry
indefinitely, otherwise it wouldn't be worthwhile.

That said, the only time the oom killer doesn't actually do something is
when it detects an exiting thread that will hopefully free memory soon or
when it detects an eligible thread that has already been oom killed and
we're waiting for it to exit. So this patch will result in an endless
series of unratelimited printk's.

Not sure that's very helpful.
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