Re: [PATCH] mm: thp: remove use_zero_page sysfs knob

[Kirill A. Shutemov]

On Sat, Jul 21, 2018 at 02:13:50AM +0800, Yang Shi wrote:
> By digging into the original review, it looks use_zero_page sysfs knob
> was added to help ease-of-testing and give user a way to mitigate
> refcounting overhead.
> 
> It has been a few years since the knob was added at the first place, I
> think we are confident that it is stable enough. And, since commit
> 6fcb52a56ff60 ("thp: reduce usage of huge zero page's atomic counter"),
> it looks refcounting overhead has been reduced significantly.
> 
> Other than the above, the value of the knob is always 1 (enabled by
> default), I'm supposed very few people turn it off by default.
> 
> So, it sounds not worth to still keep this knob around.

I don't think that having the knob around is huge maintenance burden.
And since it helped to workaround a security bug relative recently I would
rather keep it.

-- 
 Kirill A. Shutemov