Re: [PATCH v2 12/12] mm/vmscan: unify writeback reclaim statistic and throttling

Shakeel Butt
2026-04-02T03:18:08Z

On Thu, Apr 02, 2026 at 10:56:07AM +0800, Kairui Song wrote:
> On Wed, Apr 01, 2026 at 07:39:03PM +0800, Shakeel Butt wrote:
> > On Sun, Mar 29, 2026 at 03:52:38AM +0800, Kairui Song via B4 Relay wrote:
> > > From: Kairui Song <kasong@tencent.com>
> > >
[...]
> > >
> > > After this commit, congestion control is now effective and no more
> >
> > What do you mean by congestion control here?
>
> This particular case demostrated here is VMSCAN_THROTTLE_CONGESTED so
> I described it as "congestion control", may I'll just say throttling to
> avoid confusion, it's not limited to that.

Yes use throttling or VMSCAN_THROTTLE_CONGESTED directly. Congestion control
gives a networking vibe.

>
> >
> > > spin on LRU or premature OOM.
> > >
> > > Stress test on other workloads also looking good.
> > >
> > > Suggested-by: Chen Ridong <chenridong@huaweicloud.com>
> > > Signed-off-by: Kairui Song <kasong@tencent.com>
> >
> > There is still differences for global and kswapd reclaim in the shrink_node()
> > like kswapd throttling and congestion state management and throttling. Any plan
> > to unify them?
>
> Of course. Let fix it step by step,

Fine with me but better to be clear about the destination.

> this series is pretty long already.
> I originally plan to put this patch in a later series, but as Ridong
> pointed out leaving these counter updated but unused looks really
> ugly. And this fix is clean and easily to understand I think.