On Tue, 9 Jun 2015, Michal Hocko wrote:
> > Yes, and that's why I believe we should pursue that direction without the
> > associated "cleanup" that adds 35 lines of code to supress a panic. In
> > other words, there's no reason to combine a patch that suppresses the
> > panic even with panic_on_oom, which I support, and a "cleanup" that I
> > believe just obfuscates the code.
> >
> > It's a one-liner change: just test for force_kill and suppress the panic;
> > we don't need 35 new lines that create even more unique entry paths.
>
> I completely detest yet another check in out_of_memory. And there is
> even no reason to do that. Forced kill and genuine oom have different
> objectives and combining those two just makes the code harder to read
> (one has to go to check the syrq callback to realize that the forced
> path is triggered from the workqueue context and that current->mm !=
> NULL check will prevent some heuristics. This is just too ugly to
> live). So why the heck are you pushing for keeping everything in a
> single path?
>
Perhaps if you renamed "force_kill" to "sysrq" it would make more sense to
you?
I don't think the oom killer needs multiple entry points that duplicates
code and adds more than twice the lines it removes. It would make sense
if that was an optimization in a hot path, or a warm path, or even a
luke-warm path, but not an icy cold path like the oom killer.
check_panic_on_oom() can simply do
if (sysrq)
return;
It's not hard and it's very clear. We don't need 35 more lines of code to
do this.
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