From: Matthew Wilcox <willy@infradead.org>
To: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
Axel Rasmussen <axelrasmussen@google.com>
Subject: Re: [PATCH 3/3] ptdesc: Account page tables to memcgs again
Date: Wed, 25 Feb 2026 21:01:18 +0000 [thread overview]
Message-ID: <aZ9jHvd-kpnQzMgC@casper.infradead.org> (raw)
In-Reply-To: <aZ8oT-n4a8VDY2AH@linux.dev>
On Wed, Feb 25, 2026 at 08:55:54AM -0800, Shakeel Butt wrote:
> > #ifdef CONFIG_MEMCG
> > - unsigned long pt_memcg_data;
> > + struct mem_cgroup *pt_memcg;
>
> This is kernel memory, so this would be struct obj_cgroup * instead of struct
> mem_cgroup pointer. We will need something similar to __folio_objcg(), maybe
> __ptdesc_objcg() and then call obj_cgroup_memcg() on it. Basically how
> folio_memcg() handles the kernel memory.
Why would we want to do that instead of just stashing a pointer to the
memcg in the ptdesc? I feel very stupid about the differences between
all of these things and would dearly love to read some documentation to
learn.
next prev parent reply other threads:[~2026-02-25 21:01 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-25 16:22 [PATCH 0/3] Make memcg location more flexible Matthew Wilcox (Oracle)
2026-02-25 16:22 ` [PATCH 1/3] memcg: Add memcg_stat_mod() Matthew Wilcox (Oracle)
2026-02-25 19:22 ` Johannes Weiner
2026-02-25 16:22 ` [PATCH 2/3] memcg: Simplify mod_lruvec_kmem_state() Matthew Wilcox (Oracle)
2026-02-25 16:22 ` [PATCH 3/3] ptdesc: Account page tables to memcgs again Matthew Wilcox (Oracle)
2026-02-25 16:55 ` Shakeel Butt
2026-02-25 21:01 ` Matthew Wilcox [this message]
2026-02-25 20:57 ` Matthew Wilcox
2026-02-25 21:48 ` Axel Rasmussen
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