Re: [PATCH -mm -v4 00/21] mm, THP, swap: Swapout/swapin THP in one piece

From: Andrew Morton
Date: Thu Jun 28 2018 - 00:51:50 EST


On Fri, 22 Jun 2018 11:51:30 +0800 "Huang, Ying" <ying.huang@xxxxxxxxx> wrote:

> This is the final step of THP (Transparent Huge Page) swap
> optimization. After the first and second step, the splitting huge
> page is delayed from almost the first step of swapout to after swapout
> has been finished. In this step, we avoid splitting THP for swapout
> and swapout/swapin the THP in one piece.

It's a tremendously good performance improvement. It's also a
tremendously large patchset :(

And it depends upon your
mm-swap-fix-race-between-swapoff-and-some-swap-operations.patch and
mm-fix-race-between-swapoff-and-mincore.patch, the first of which has
been floating about since February without adequate review.

I'll give this patchset a spin in -mm to see what happens and will come
back later to take a closer look. But the best I can do at this time
is to hopefully cc some possible reviewers :)