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From: Johannes Weiner <hannes@cmpxchg.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Qu Wenruo <quwenruo.btrfs@gmx.com>, Qu Wenruo <wqu@suse.com>,
	linux-btrfs@vger.kernel.org, mhocko@kernel.org,
	roman.gushchin@linux.dev, shakeel.butt@linux.dev,
	muchun.song@linux.dev, akpm@linux-foundation.org,
	cgroups@vger.kernel.org, linux-mm@kvack.org,
	Michal Hocko <mhocko@suse.com>,
	"Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Subject: Re: [PATCH] btrfs: root memcgroup for metadata filemap_add_folio()
Date: Thu, 3 Oct 2024 16:58:53 -0400	[thread overview]
Message-ID: <20241003205853.GA1658449@cmpxchg.org> (raw)
In-Reply-To: <Zvz5KfmB8J90TLmO@infradead.org>

On Wed, Oct 02, 2024 at 12:41:29AM -0700, Christoph Hellwig wrote:
> > > This looks pretty ugly.  What speaks against a version of
> > > filemap_add_folio that doesn't charge the memcg?
> 
> What I'd propose is something like the patch below, plus proper
> documentation.

I like this much better as well.

> Note that this now does the uncharge on the unlocked folio in the
> error case.  From a quick look that should be fine, but someone who
> actually knows the code needs to confirm that.

That's fine. For the same reason the non-atomic __folio_clear_locked()
is fine in that case. The folio just has to be exclusive.


      parent reply	other threads:[~2024-10-03 20:59 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-28  4:45 Qu Wenruo
2024-09-30 17:23 ` Shakeel Butt
2024-09-30 22:00   ` Qu Wenruo
2024-10-01  1:37     ` Shakeel Butt
2024-10-01  2:03       ` Qu Wenruo
2024-10-01  9:19 ` Christoph Hellwig
2024-10-01  9:40   ` Qu Wenruo
2024-10-02  7:41     ` Christoph Hellwig
2024-10-03  8:07       ` Michal Hocko
2024-10-03 20:39         ` Shakeel Butt
2024-10-03  8:11       ` Qu Wenruo
2024-10-03  8:22         ` Michal Hocko
2024-10-03  8:23           ` Qu Wenruo
2024-10-03 20:58       ` Johannes Weiner [this message]

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