Re: [PATCH] mm: Free unused swap cache page in write protection fault handler

[Linus Torvalds]

On Tue, Jan 12, 2021 at 9:24 PM huang ying <huang.ying.caritas@xxxxxxxxx> wrote:
> >
> > Couldn't we just move it to the tail of the LRU list so it's reclaimed
> > first?  Or is locking going to be a problem here?
>
> Yes.  That's a way to reduce the disturbance to the page reclaiming.
> For LRU lock contention, is it sufficient to use another pagevec?

I wonder if this is really worth it. I'd like to see numbers.

Because in probably 99%+ of all cases, that LRU dance is only going to
hurt and add extra locking overhead and dirty caches.

So I'd like to see some numbers that it actually helps measurably in
whatever paging-heavy case...

            Linus