Re: [PATCH] mm: Make mem_cgroup_id_get_many dependent on MMU and MEMCG_SWAP

[Chris Down]

Johannes Weiner writes:
> I would ack a patch that adds __maybe_unused.
>
> This is a tiny function. If we keep it around a few releases after
> removing the last user, it costs us absolutely nothing. Eventually
> somebody will notice and send a patch to remove it. No big deal.
>
> There is, however, real cost in keeping bogus warnings around and
> telling people to ignore them. It's actively lowering the
> signal-to-noise ratio and normalizing warnings to developers. That's
> the kind of thing that will actually hide problems in the kernel.
>
> We know that the function can be unused in certain scenarios. It's
> silly to let the compiler continue to warn about it. That's exactly
> what __maybe_unused is for, so let's use it here.

Yeah, this is exactly what I was trying to express in the first one[0]. The 
fact that this patch came around a second time, as expected, just solidifies my 
concern around the waste to human time.

I would also ack a patch that adds __maybe_unused.

0: https://lore.kernel.org/linux-mm/20191217143720.GB131030@xxxxxxxxxxxxxx/