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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=jqYvau3y; 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 8C877606A335; Thu, 12 Nov 2026 08:37:04 +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=jqYvau3y Received: by smtp.kernel.org (Postfix) with ESMTPSA id D40DE1F00A13; Thu, 12 Nov 2026 08:37:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794472624; bh=/yEdPtHpJ1NtcQC60gYn0MUtGO5PcvthVLd0v02et/I=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=jqYvau3yOeSxB1kD7U3L2EBRpoOqvpE7k1VJV+6JuPIQNEtd9OKlj0k96CfLYRUmw k975HhQUdKJzCdMO/SYXH4ORvvUC7VKbCqcZlbKFVngVPOjniEojfCvoswjg2X1f4W AkWZsppHZgrlkxPj0Kkv2cEHcejVuJic610j9dC1GvTynDFVs3YGuqQ9pBMcWRBQID J9dtYWYeCi5vTSp+FKk5fEFFxs3T+WPl/iHlti8oBLV/UWpzvy3B9KXgYxZevgQ52X CalQuYCSTcxyR0EOiUzmQ/G2zhpd5OstOQgaL5U9Z5j5Dsr313YLlfpPJ3IFF/Kw6I ig5dG3E0hkQsQ== Message-ID: Date: Thu, 12 Nov 2026 09:36:57 +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 2/3] mm: gup: allow long-term pins of CMA-allocated HugeTLB folios To: Frank van der Linden , Qi Zheng Cc: muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, azpijr@gmail.com, lance.yang@linux.dev, Qi Zheng , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org References: <586d6c53ab7e4c64d6e89ad3cf0cf7e07dabbfaf.1794046188.git.zhengqi.arch@bytedance.com> <7abb3aa1-385a-422f-86bd-7aac9661c4d8@kernel.org> <423c9b28-ecf2-4fab-817d-2fb326690c73@linux.dev> <3a1a3bb5-0b01-4f20-aa0e-74a952544b8c@kernel.org> <5f68ffba-9f56-4e31-9e7c-9d110f552efc@bytedance.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 11/11/26 23:26, Frank van der Linden wrote: > On Wed, Nov 11, 2026 at 2:27 AM Qi Zheng wrote: >> >> Hi David, >> >> On 11/11/26 3:43 PM, David Hildenbrand (Arm) wrote: >>> >>> You resent your series way too fast. >> >> Got it. >> >>> >>> Now we have discussions in to threads, congratulations ;) >>> >>> >>> Why can't that be resolved differently? What is the dependency? >> >> The dependency is that the new check wants to use >> `folio_test_hugetlb_cma()`, which is a HugeTLB-specific inline helper >> from `include/linux/hugetlb.h`. >> >> `folio_is_longterm_pinnable()` currently lives in `include/linux/mm.h`, >> while `include/linux/hugetlb.h` already includes `linux/mm.h`. So I >> can't simply use `folio_test_hugetlb_cma()` from `mm.h` >> >>> >> >> The more accurate code path is as follows. >> >> Assuming the 2M buddy allocation is successful, page P is borrowed from >> the 1G CMA area. >> >> Now, proceed to request a new 1G huge page: >> >> only_alloc_fresh_hugetlb_folio >> --> alloc_gigantic_frozen_folio >> --> hugetlb_cma_alloc_frozen_folio >> --> cma_range_alloc >> /* set bitmap!! */ >> --> bitmap_set(cmr->bitmap, bitmap_no, bitmap_count); >> >>