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smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="dK91/CBD"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5DADB606A889; Thu, 12 Nov 2026 09:08:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=dK91/CBD Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4979C1F00A05; Thu, 12 Nov 2026 09:08:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794474506; bh=sT5JORa4hluQX/UGABU9ltevF9DMtn7AClnTuZFBi64=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=dK91/CBDUKHnx4fnxpXkYT6g6EjYNWdbEfh28QaH4eiXnsV7Q65lDqVP7CnvE/zD7 3PL8LPJSkPlTXKqXQzkgMcC6n9oadyiqPqaJ9OF34qhg86EiHvtApGY8+jOLYvnrYx qly7FN3cuvvW7NQV/qLx8+0BJlyHWHjTc5Iar9JQ0rKVKYAR9Bfm8GlYty1323KO0S J04aUVbMlpTo5op0oUgccIMziBFU87+0zggpYiSVWSQCj2jUOHloi27gGFT/Nd/ysB QdHoyqzJDffQdW6oAxuFCBOd4NijXG9eV0U6VyzlVUDPyQwZO+dbO9y81oIC2gPQRL gbnVwvLiJ/FEA== Message-ID: Date: Thu, 12 Nov 2026 10:04:51 +0100 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 3/5] mm/memory-failure: Add a pre-online poison registry To: Shaikh Kamaluddin , Davidlohr Bueso , Jonathan Cameron , Dave Jiang , Alison Schofield , Vishal Verma , Dan Williams , Miaohe Lin , Andrew Morton , Vlastimil Babka , Breno Leitao Cc: Ira Weiny , Li Ming , Richard Cheng , Naoya Horiguchi , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Oscar Salvador , Kiryl Shutsemau , Harry Yoo References: <20261010162017.62506-1-shaikhkamal2012@gmail.com> <20261010162017.62506-4-shaikhkamal2012@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/10/26 18:20, Shaikh Kamaluddin wrote: > A frame can be known bad before its backing memory is onlined. A CXL > Type-3 device retains poison as DPA-based Media Error Records and can > report those records through GET_POISON_LIST after a reboot, kexec, or > device hotplug. > > CXL poison can be retrieved while a region is being prepared, before > dax/kmem calls add_memory_driver_managed() for the range. At that point > there is no initialized struct page on which memory_failure() can > operate. The poison information must therefore be retained until the > corresponding pages pass through memory initialization. > > Add a registry of sorted, nonoverlapping poisoned PFN ranges. Each > registration represents one owner and its independently managed memory. > For example, a CXL region registers the poisoned PFN ranges translated > from its device poison records and receives an opaque handle for that > range set. A second CXL region receives a separate handle for its own > ranges. > > The owner uses its handle to remove exactly its registration after the > associated memory can no longer enter the allocator. Removing one CXL > region's registration does not affect poison ranges registered by > another region. > > Keep each registered range set immutable and protect the registration > list with RCU. This keeps allocator-side lookups lockless while allowing > a registration to be removed safely after an RCU grace period. A later > patch will consult the registry before initialized pages are released > to the buddy allocator. > > Signed-off-by: Shaikh Kamaluddin > --- Oh no, another source of poison information. That doesn't sound like a good design. -- Cheers, David