Re: [RFC PATCH 1/3] mm: Drop locked from isolate_migratepages_block

Alexander Duyck
2020-08-13T14:32:46Z

On Wed, Aug 12, 2020 at 11:57 PM Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org> wrote:
>
>
>
> 在 2020/8/13 下午12:02, Alexander Duyck 写道:
> > From: Alexander Duyck <alexander.h.duyck-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> >
> > We can drop the need for the locked variable by making use of the
> > lruvec_holds_page_lru_lock function. By doing this we can avoid some rcu
> > locking ugliness for the case where the lruvec is still holding the LRU
> > lock associated with the page. Instead we can just use the lruvec and if it
> > is NULL we assume the lock was released.
> >
> > Signed-off-by: Alexander Duyck <alexander.h.duyck-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> > ---
> > mm/compaction.c | 45 ++++++++++++++++++++-------------------------
> > 1 file changed, 20 insertions(+), 25 deletions(-)
>
> Thanks a lot!
> Don't know if community is ok if we keep the patch following whole patchset alone?

I am fine with you squashing it with another patch if you want. In
theory this could probably be squashed in with the earlier patch I
submitted that introduced lruvec_holds_page_lru_lock or some other
patch. It is mostly just a cleanup anyway as it gets us away from
needing to hold the RCU read lock in the case that we already have the
correct lruvec.