linux-kernel - Re: [PATCH] mm: mark folio as workingset in lru_deactivate

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Message-ID: <CAGWkznEOfyULrBOR=AJRKPdPrED+xwrtGbLXEaFmWr1xfFbOuA@mail.gmail.com>
Date:   Mon, 3 Apr 2023 16:18:53 +0800
From:   Zhaoyang Huang <huangzhaoyang@...il.com>
To:     Johannes Weiner <hannes@...xchg.org>
Cc:     "zhaoyang.huang" <zhaoyang.huang@...soc.com>,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, ke.wang@...soc.com
Subject: Re: [PATCH] mm: mark folio as workingset in lru_deactivate_fn

On Thu, Mar 30, 2023 at 5:41 PM Zhaoyang Huang <huangzhaoyang@...il.com> wrote:
>
> On Thu, Mar 30, 2023 at 5:32 PM Johannes Weiner <hannes@...xchg.org> wrote:
> >
> > On Thu, Mar 30, 2023 at 09:38:48AM +0800, Zhaoyang Huang wrote:
> > > On Wed, Mar 29, 2023 at 10:55 PM Johannes Weiner <hannes@...xchg.org> wrote:
> > > >
> > > > On Wed, Mar 29, 2023 at 06:47:35PM +0800, zhaoyang.huang wrote:
> > > > > From: Zhaoyang Huang <zhaoyang.huang@...soc.com>
> > > > >
> > > > > folio will skip of being set as workingset in lru_deactivate_fn.
> > > >
> > > > Can you please elaborate why that's undesirable? What's the problem
> > > > you're fixing?
> > > If I am correct, folio will skip being set as workingset when moving
> > > from active lru to inactive lru, which is performed on every folio in
> > > shrink_active_list during normal reclaim.
> >
> > shrink_active_list directly calls folio_set_workingset(). The function
> > you're editing is used for things like MADV_COLD and truncate().
> Yes.
> >
> > It sounds like there is just a misunderstanding of the code, not an
> > actual problem.
> Isn't that a problem? As my understanding, MADV_COLD could be deemed
> as a stimulation of normal reclaiming which turbo the folio towards
> eviction, while the page moving by it should be also delt in the same
> way(PG_active has been cleaned)
Sorry, I am still confused. Does it mean the pages deactivated via
MADV_COLD like methods should NOT be deemed as workingset pages?