Re: [PATCH v2 00/28] Eliminate Dying Memory Cgroup

[Harry Yoo]

On Mon, Dec 29, 2025 at 03:48:26PM +0800, Qi Zheng wrote:
> 
> 
> On 12/24/25 7:20 AM, Shakeel Butt wrote:
> > On Tue, Dec 23, 2025 at 08:04:50PM +0000, Yosry Ahmed wrote:
> > [...]
> > > 
> > > I think there might be a problem with non-hierarchical stats on cgroup
> > > v1, I brought it up previously [*]. I am not sure if this was addressed
> > > but I couldn't immediately find anything.
> > 
> > Sigh, the curse of memcg-v1. Let's see what we can do to not break v1.
> 
> The memcg-v1 was originally planned to be removed, could we skip
> supporting v1?

You mean not reparenting LRU pages if CONFIG_MEMCG_V1 is set?

That may work, but IMHO given that there is no clear timeline for removal
yet (some v1-specific features have been officially deprecated,
but memcg v1 as a whole hasn't), implementing Shakeel's suggestion [1]
may be a good option (it doesn't seem to add much complexity)

But it can be argued that it's not good enough reason to
delay the series; adding support for V1 later sounds sensible to me.

Anyway I'm fine either way and I'm not a memcg maintainer myself,
so this is just my two cents.

[1] https://lore.kernel.org/linux-mm/wvj4w7ifmrifnh5bvftdziudsj52fdnwlhbt2oifwmxmi4eore@ob3mrfahhnm5/

-- 
Cheers,
Harry / Hyeonggon