From: Matthew Wilcox <willy@infradead.org>
To: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Boris Burkov <boris@bur.io>,
akpm@linux-foundation.org, linux-btrfs@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
kernel-team@fb.com, wqu@suse.com, mhocko@kernel.org,
muchun.song@linux.dev, roman.gushchin@linux.dev,
hannes@cmpxchg.org
Subject: Re: [PATCH v3 2/4] mm: add vmstat for cgroup uncharged pages
Date: Wed, 20 Aug 2025 14:19:24 +0100 [thread overview]
Message-ID: <aKXLXJw7m-TSkZOI@casper.infradead.org> (raw)
In-Reply-To: <i4hg4g75ywbera643uhtshkj6xrriqi4mi5dg3oga5os3tp6m5@u2dcv2snbiqs>
On Tue, Aug 19, 2025 at 06:25:36PM -0700, Shakeel Butt wrote:
> On Wed, Aug 20, 2025 at 12:46:43AM +0100, Matthew Wilcox wrote:
> > OK, but couldn't we make that argument for anything else? Like slab,
> > say. Why's "file" memory different?
>
> Good point and I think it does apply to other memory types too. I would
> call "file" memory to be more important as it is one of the largest
> consumer of DRAM on, at least, Meta infra. Slab needs a bit more thought.
> At the system level (i.e. /proc/meminfo), we account at the page (or
> slab) level while for memcg, we account per-object (plus obj_cgroup
> pointer).
That was supposed to be a reductio ad absurdum, not an invitation to
add more counters.
Look, if this is information you really need, I think you should come
up with a better way of collecting it than by adding new counters and
new complexity to everything involved in GFP_ACCOUNT activities.
The unaccounted address_spaces are a very tiny percentage of file
memory, at least as far as this patch set goes. I don't think this
patch is justifiable on its face.
next prev parent reply other threads:[~2025-08-20 13:19 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-19 0:36 [PATCH v3 0/4] introduce uncharged file mapped folios Boris Burkov
2025-08-19 0:36 ` [PATCH v3 1/4] mm/filemap: add AS_UNCHARGED Boris Burkov
2025-08-19 2:46 ` Matthew Wilcox
2025-08-19 3:57 ` Boris Burkov
2025-08-20 22:06 ` Klara Modin
2025-08-20 22:22 ` Shakeel Butt
2025-08-20 22:52 ` Boris Burkov
2025-08-20 23:15 ` Klara Modin
2025-08-20 23:53 ` Shakeel Butt
2025-08-21 19:37 ` Shakeel Butt
2025-08-19 0:36 ` [PATCH v3 2/4] mm: add vmstat for cgroup uncharged pages Boris Burkov
2025-08-19 2:50 ` Matthew Wilcox
2025-08-19 4:05 ` Boris Burkov
2025-08-19 15:53 ` Shakeel Butt
2025-08-19 23:46 ` Matthew Wilcox
2025-08-20 1:25 ` Shakeel Butt
2025-08-20 13:19 ` Matthew Wilcox [this message]
2025-08-20 16:21 ` Shakeel Butt
2025-08-19 0:36 ` [PATCH v3 3/4] btrfs: set AS_UNCHARGED on the btree_inode Boris Burkov
2025-08-19 0:36 ` [PATCH v3 4/4] memcg: remove warning from folio_lruvec Boris Burkov
2025-08-19 2:41 ` Matthew Wilcox
2025-08-19 5:20 ` Andrew Morton
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