Re: [PATCH] mm: split thp synchronously on MADV_DONTNEED

[Matthew Wilcox]

On Sat, Nov 20, 2021 at 12:12:30PM -0800, Shakeel Butt wrote:
> This patch let such applications not worry about the low level handling
> of THPs in the kernel and splits the THPs synchronously on
> MADV_DONTNEED.

I don't mind the synchronous split, but I have concerns about the
implementation.  I don't think it's worth another pointer in task_struct.
It's also the case that splitting is likely to succeed, so I think a
better implementation would try to split and then put the page on the
global deferred list if splitting fails.