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Wed, 22 Jul 2026 06:14:13 -0700 (PDT) Date: Wed, 22 Jul 2026 09:14:10 -0400 From: Johannes Weiner To: Youngjun Park Cc: akpm@linux-foundation.org, chrisl@kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kasong@tencent.com, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, shikemeng@huaweicloud.com, baoquan.he@linux.dev, baohua@kernel.org, yosry@kernel.org, joshua.hahnjy@gmail.com, gunho.lee@lge.com, taejoon.song@lge.com, hyungjun.cho@lge.com, baver.bae@lge.com, her0gyugyu@gmail.com Subject: Re: [PATCH v10 0/6] mm/swap, memcg: Introduce swap tiers for cgroup based swap control Message-ID: References: <20260713025644.170839-1-youngjun.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260713025644.170839-1-youngjun.park@lge.com> X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: CAFE7A000B X-Stat-Signature: fcmjrhatt91qp8qjxojxfytr7jycaqj9 X-HE-Tag: 1784726055-344074 X-HE-Meta: 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 exJ3EHxA DnzZ0aW+XNFp3kd+cVpxpop+KVFD3uGa/WiI0v+fa0425ottWKwqOkLEoGFrfBXEG16omPA7gD/ZfR6YELYFIOlQ/CYi72XIAu2im5G6jGjISHunWy/VHvZdHBHqxC3n0KqLDulkuXJcplNb41ZPoxO6GlZ9v+OR2BlK4tmwfGOAOP070ZuTEBeEFqYZ2A9KJH3sXSIldjarlS2M8jYwqge2rKLwtw84IR7MsQTEzEgJxgFbu5zsUYSFyY/H2p8zbVLle/S8tu45GTNZagaXyHUy+x7Q5HQiHT6vRGs21i45O/9Uny9ORl20eLBtsnG9mtvXBh6oDsfG0paPKY9urN5JXgjHcAHSbTWEOqTF67gfZgcuzXXE605/Ic44LqmmR7gwo60H1eh0O0/GGHvTKHAEcqmvo7fKfM5zt+pJ5cOnqXv/yfR21zYBJxsuKG9jT9DAMzeXfbYC66b+cUFzO2TsdcQTd534RO+eJ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Zswap is a first-order swap destination with writeback semantics. The way the discussion around zswap has been going in this thread is disappointing, and I don't feel comfortable adding permanent user interfaces on this basis. We will not be merging a memcg swap tier interface until the swap side has a story for indirection and backend migration.