Re: [PATCH] memcg, kmem: do not fail __GFP_NOFAIL charges

[Michal Hocko]

On Wed 11-09-19 07:37:40, Andrew Morton wrote:
> On Wed, 11 Sep 2019 14:00:02 +0200 Michal Hocko <mhocko@xxxxxxxxxx> wrote:
> 
> > On Mon 09-09-19 13:22:45, Michal Hocko wrote:
> > > On Fri 06-09-19 11:24:55, Shakeel Butt wrote:
> > [...]
> > > > I wonder what has changed since
> > > > <http://lkml.kernel.org/r/20180525185501.82098-1-shakeelb@xxxxxxxxxx/>.
> > > 
> > > I have completely forgot about that one. It seems that we have just
> > > repeated the same discussion again. This time we have a poor user who
> > > actually enabled the kmem limit.
> > > 
> > > I guess there was no real objection to the change back then. The primary
> > > discussion revolved around the fact that the accounting will stay broken
> > > even when this particular part was fixed. Considering this leads to easy
> > > to trigger crash (with the limit enabled) then I guess we should just
> > > make it less broken and backport to stable trees and have a serious
> > > discussion about discontinuing of the limit. Start by simply failing to
> > > set any limit in the current upstream kernels.
> > 
> > Any more concerns/objections to the patch? I can add a reference to your
> > earlier post Shakeel if you want or to credit you the way you prefer.
> > 
> > Also are there any objections to start deprecating process of kmem
> > limit? I would see it in two stages
> > - 1st warn in the kernel log
> > 	pr_warn("kmem.limit_in_bytes is deprecated and will be removed.
> > 	        "Please report your usecase to linux-mm@xxxxxxxxx if you "
> > 		"depend on this functionality."
> 
> pr_warn_once() :)
> 
> > - 2nd fail any write to kmem.limit_in_bytes
> > - 3rd remove the control file completely
> 
> Sounds good to me.

Here we go