Re: [PATCH] Lock mmap_sem when calling migrate_pages() in do_move_pages_to_node()

[Michal Hocko]

On Tue 30-01-18 14:12:28, Zi Yan wrote:
> On 30 Jan 2018, at 11:10, Michal Hocko wrote:
[...]
> I think the question is whether we need to hold mmap_sem for
> migrate_pages(). Hugh also agrees it is not necessary on a separate
> email. But it is held in the original code.

I would be really surprised if we really needed the lock. If we do,
however, then we really need a very good explanation why. The code used
to do so is not a valid reason.

-- 
Michal Hocko
SUSE Labs