Re: [PATCH v2] fs: fsnotify: account fsnotify metadata to kmemcg

[Shakeel Butt]

On Wed, Jan 24, 2018 at 5:54 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> On Wed, Jan 24, 2018 at 05:08:27PM -0800, Shakeel Butt wrote:
>> First, let me apologize, I think I might have led the discussion in
>> wrong direction by giving one wrong information. The current upstream
>> kernel, from the syscall context, does not invoke oom-killer when a
>> memcg hits its limit and fails to reclaim memory, instead ENOMEM is
>> returned. The memcg oom-killer is only invoked on page faults. However
>> in a separate effort I do plan to converge the behavior, long
>> discussion at <https://patchwork.kernel.org/patch/9988063/>.
>
> Correct me if I'm misinterpreting you, but your rationale in there
> appears to be along the lines of "userland applications might not
> be ready to handle -ENOMEM gracefully, so let's hit them with
> kill -9 instead - that will be handled properly, 'cuz M4G1C!!1!!!!"
>

Nah, the motivation is something like: In the memory overcommitted
system (or memcg) where jobs of different priorities are running, it
is preferable to kill a low priority job than to return an ENOMEM to
high priority job.