Re: [PATCH for-7.4 0/9] memcg: remove the v1 soft limit

[Shakeel Butt]

On Fri, Aug 28, 2026 at 07:43:22PM -0700, Andrew Morton wrote:
> On Fri, 28 Aug 2026 19:23:19 -0700 Shakeel Butt <shakeel.butt@xxxxxxxxx> wrote:
> 
> > On Tue, Aug 11, 2026 at 01:31:54PM -0700, Shakeel Butt wrote:
> > > Syzbot reported [1] a set_mm_walk() warning from kswapd. Soft limit
> > > reclaim is the only thing that runs shrink_lruvec() from kswapd with a
> > > target memcg set, and thus the only way kswapd can reach
> > > lru_gen_shrink_lruvec() and in turn set_mm_walk(). The offender,
> > > mem_cgroup_shrink_node(), has long carried a "Only used by soft limit
> > > reclaim. Do not reuse for anything else." comment and a priority hack,
> > > and it simply never got taught about MGLRU.
> > > 
> > > Rather than teach it, let's delete it. The v1 soft limit was deprecated
> > > in v6.12 by commit 569c4f62d84a ("memcg: initiate deprecation of v1
> > > soft limit"). Nobody has reported depending on it in the ~21 months
> > > since, and v2 has covered the same ground for a long time with
> > > memory.low and memory.min.
> > > 
> > > Link: https://lore.kernel.org/all/6a7a6929.b50370da.49fe0.005e.GAE@xxxxxxxxxx/ [1]
> > 
> > Andrew, should I resend this series (without the first patch) or will you pick
> > it up?
> 
> I added the series, thanks.
> 
> The [1/9] has already been queued in mm-hotfixes as a backportable
> hotfix.  So I added it as an 8-patch series.  Because of this the cover
> letter of that series is now irrelevant, so could you please prepare a
> brief replacement for me to paste in?
> 
> Sashiko suggests that there's more that can be removed:
> 	https://sashiko.dev/#/patchset/20260811203203.3456029-1-shakeel.butt@xxxxxxxxx
> 
> So maybe an 8-patch v2 series is appropriate, your call.

I will send 8-patch v2 series with Sashiko's comments resolved by next week.