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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=RcLnxpyV; 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 73021606A31C for ; Wed, 11 Nov 2026 22:05:57 +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=RcLnxpyV Received: by smtp.kernel.org (Postfix) with ESMTPSA id 907651F00A05; Wed, 11 Nov 2026 22:05:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794434757; bh=G3z7N08vif0wJRzAYglj+deRTAnEekHHdYmVnN3upqU=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=RcLnxpyV70qsh/dFqhzFKXXRCnk0lw3j5tRW3S6jFBCsMz5CimfxFkneTy393fygZ 9SZiQrEtUg3kb9UtPQbGD4rRD+YHD+5lJX8ecb+d1lmv7MVXFwsioKxzo6kDXczO+7 PWD4XK9pOCcYN6bo3uBym/P60/MJ/4hCVwdKy5+fRdnuD1MRWPaC87Y+KwF7SGsyNJ XqhEId3JvQUSkk2wtZwkb5h/1Bm6YeuDCmPbi79zzjSIQm/0oYUGjvHZU76Uh/lrB3 n364Rlotx2DTPRpZ5e+XCbJZ8ja72YQzY4rzcI6eGqmpOelgt1hP9UKdz+XEsZFJ+j otHKNQaM5yfxg== Message-ID: Date: Wed, 11 Nov 2026 23:05:50 +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: [PATCH v3 0/3] mm: hugetlb: fix CMA-related issues To: Qi Zheng , muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, azpijr@gmail.com, lance.yang@linux.dev Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Qi Zheng References: 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 11/7/26 11:30, Qi Zheng wrote: > From: Qi Zheng > > Hi all, > > This series fixes three CMA-related issues in HugeTLB reservation, > long-term pinning and allocation: > Can I hand you over another CMA-related hugetlb problem? On arm64, we can end up allocating 1GiB and 32MiB hugetlb folios from the cma region. Doing that dynamically is not a problem. Doing it during boot doesn't quite work. cma_reserve_early() does not handle any kind of alignment. So if you allocate a 32M folio followed by a 1G folio, the 1G folio will suddenly start at offset 32M, not being naturally aligned in physical address space. Likely cma_reserve_early() must be taught to align (and maybe consume an order instead of a size), similar to how the dynamic cma allocations work. -- Cheers, David