From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A17B39183A for ; Fri, 31 Jul 2026 14:13:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785507238; cv=none; b=ovs1KF/li81EztXhRHNVIJCRtxHpq+6XZJGMU8JNifslmcka5lSf3V/Vmse9BewXFlbLdaFPz7wnI++YllZ5ytQ3YVsWRtQ2gHRn/3kqP+zBz2xua8jPtvN6W1h++8k31Iu85IOyanRpo1y7s5M2xCtuwyMxZknKqqk1xb8qpmk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785507238; c=relaxed/simple; bh=QwexmUafRXYwlzJwLzNCNkLlpcNdYu79PnXmdTJbsQo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=KaZm9klXr6COBv8IoBsZwvgtUJVWKJOlFHD27pc3E6eV0VlhNjTH9ycYoD0VZtdYPycwBcNs2z1sa9Crb9rBZIV8MqWj8EbhQzB8WFMrDGn6PQTO950bzvRNolOjQ1GxAC++fEH06Zu4/9ZVtTkBXSEySxKXesvpTX+Yo2p+QIc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YigsGhKL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YigsGhKL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A82751F000E9; Fri, 31 Jul 2026 14:13:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785507236; bh=Y/41p4/Kr/MVi4hSJAjbKgh4tTo8fUdwQ7XoxvN9Mx4=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=YigsGhKLHAS1cw4q3uoFzwBffhZ8H3PN7g5JvVhSdCE3LGi5D4xlnJxVQ/41Qh3OJ k93K3uVnQeWymvZ9/2zXtjabw6KxidwLG7oBUPjtnQutYilyAlDA1wzlKvJj+V57v9 kgvu+7zrqTYTmma1qy1Q8ef8mryAaDvdSyrLVncX0LhdQd8L/DEvPbQR2454slyynJ b9wUUP/02ooIKyJYBv03FFsQso8c9XK99GtIjqOYEH61EmuaiWpnRDL1Rc2iuecjYK K+ZAfZxB2+z97igjuJCEppXdQ/4ubhuFHUve8CiJBcd6uBu64Za6hOm/8+jpTBxPxm Belb0pPocadGw== Message-ID: Date: Fri, 31 Jul 2026 16:13:50 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 15/26] mm/page_alloc: add support for freetypes with no freelist Content-Language: en-US To: Brendan Jackman , Borislav Petkov , Dave Hansen , Peter Zijlstra , Andrew Morton , David Hildenbrand , Mike Rapoport , Wei Xu , Johannes Weiner , Zi Yan , Lorenzo Stoakes Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, Sumit Garg , Will Deacon , rientjes@google.com, "Kalyazin, Nikita" , patrick.roy@linux.dev, "Itazuri, Takahiro" , Andy Lutomirski , David Kaplan , Thomas Gleixner , Yosry Ahmed , Patrick Bellasi , Reiji Watanabe , Sean Christopherson References: <20260726-page_alloc-unmapped-v3-0-6f5729aa9832@google.com> <20260726-page_alloc-unmapped-v3-15-6f5729aa9832@google.com> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/27/26 00:22, Brendan Jackman wrote: > Freetypes are currently just a wrapper for migratetypes, but in a later > patch they will gain flags. The theoretically possible space of > freetypes will thus grow, but many freetypes will not actually be used > in practice. > > To avoid bloating structures that contain arrays of freelists, mark > freetype_idx() as possibly returning -1, and add handling of this case > to code paths that will look up freelists by freetype (unless those > paths "know" that they're operating on a freetype that has a > valid freetype_idx). > > It never actually returns -1 yet, this is just introduced as a separate > patch to make review easier. > > Signed-off-by: Brendan Jackman Reviewed-by: Vlastimil Babka (SUSE)