From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0B709D44C7A for ; Thu, 15 Jan 2026 16:34:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5B5546B0088; Thu, 15 Jan 2026 11:34:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 58D5D6B0089; Thu, 15 Jan 2026 11:34:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4AD306B008A; Thu, 15 Jan 2026 11:34:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 3CE736B0088 for ; Thu, 15 Jan 2026 11:34:08 -0500 (EST) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id DDDA916041C for ; Thu, 15 Jan 2026 16:34:07 +0000 (UTC) X-FDA: 84334745334.25.86D6F10 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf24.hostedemail.com (Postfix) with ESMTP id 17E29180017 for ; Thu, 15 Jan 2026 16:34:05 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=quFB9Of5; spf=pass (imf24.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1768494846; a=rsa-sha256; cv=none; b=A4UD88oGdTSyBjgNnWXSahgRFAByx9WuXmXgElc7uVMqH5AUd0iGSFNRboUkbdUSmQuj6w QnSzGKjliaZZHug1c7UClraLeMcLTwu0JWTi0KHNGv0nGHwL5EotkxIfAl2Xx1246hKCuH Fo7o7/ob40Pqb3a7eQHH5VpyyFFNOmY= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=quFB9Of5; spf=pass (imf24.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1768494846; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Nig7yH3SuIFztXEniKHzh3YF8SfC3vJxnJ3N5O0Eaks=; b=lbYvoyCC/IiM4jzx30/DLuS24rlZc8bF5uzQhv67SxSUWYdBLkD+zcBU9ZVCPN0jPFKYrU 0BU1/vFqxfeWqhtkuYEIxyQuezkMxdNguojnJAvnVLFYF1IfCLWUnCerWt6SXG4cNMdhsW JRIcl0v2fpJ32cYI6RNzKsGdf3LjPdc= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id C3FE143FEF; Thu, 15 Jan 2026 16:34:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9C67C19422; Thu, 15 Jan 2026 16:33:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768494844; bh=8hxhpYwatqg4ec2o/1bKwmlVi3StWJTQEmDCQHBf2HM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=quFB9Of5eORu4Ot6l7yrlb+gSDrL7IV3sLfpi/BGIn2H5RovR9oIfLoMmaCjZF0UT aCgMWFBfwSVPIcRSBogpaoSibyzYGdFaEWbRQ7BYgQdm/JAinkyAwmmoMDoMQB8jet w1WlHBNhXCkYAa0S7greRyO98Vwu06B1uqXshcYQrAGpK5+DYRPN2deju3oBzqIVGy R13VoFjcpRxkKR8fYKdRz74vwVOKSm4AjkK4sW7rP+1AcSSbJY7y4XUNCTsFbaYWkk 5G3Cx2mCBnDJnuVrNyMGv0b7OYo6/nsxYV5WX8wVOjAu+56KS7Lo19VFPw7E1dePHH SIoChbZRn1Rmw== Message-ID: <37fdb994-59d1-4196-b377-f3f749148b19@kernel.org> Date: Thu, 15 Jan 2026 17:33:56 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 22/23] mm: rename CONFIG_MEMORY_BALLOON -> CONFIG_BALLOON To: Lorenzo Stoakes Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, Broadcom internal kernel review list , linux-doc@vger.kernel.org, virtualization@lists.linux.dev, Andrew Morton , Oscar Salvador , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Arnd Bergmann , Greg Kroah-Hartman , Jerrin Shaji George , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?Q?Eugenio_P=C3=A9rez?= , Zi Yan References: <20260115092015.3928975-1-david@kernel.org> <20260115092015.3928975-23-david@kernel.org> <219f7be4-8355-4376-bf97-3410c6e23867@lucifer.local> From: "David Hildenbrand (Red Hat)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAa2VybmVsLm9yZz7CwY0EEwEIADcWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCaKYhwAIbAwUJJlgIpAILCQQVCgkIAhYCAh4FAheAAAoJEE3eEPcA/4Naa5EP/3a1 9sgS9m7oiR0uenlj+C6kkIKlpWKRfGH/WvtFaHr/y06TKnWn6cMOZzJQ+8S39GOteyCCGADh 6ceBx1KPf6/AvMktnGETDTqZ0N9roR4/aEPSMt8kHu/GKR3gtPwzfosX2NgqXNmA7ErU4puf zica1DAmTvx44LOYjvBV24JQG99bZ5Bm2gTDjGXV15/X159CpS6Tc2e3KvYfnfRvezD+alhF XIym8OvvGMeo97BCHpX88pHVIfBg2g2JogR6f0PAJtHGYz6M/9YMxyUShJfo0Df1SOMAbU1Q Op0Ij4PlFCC64rovjH38ly0xfRZH37DZs6kP0jOj4QdExdaXcTILKJFIB3wWXWsqLbtJVgjR YhOrPokd6mDA3gAque7481KkpKM4JraOEELg8pF6eRb3KcAwPRekvf/nYVIbOVyT9lXD5mJn IZUY0LwZsFN0YhGhQJ8xronZy0A59faGBMuVnVb3oy2S0fO1y/r53IeUDTF1wCYF+fM5zo14 5L8mE1GsDJ7FNLj5eSDu/qdZIKqzfY0/l0SAUAAt5yYYejKuii4kfTyLDF/j4LyYZD1QzxLC MjQl36IEcmDTMznLf0/JvCHlxTYZsF0OjWWj1ATRMk41/Q+PX07XQlRCRcE13a8neEz3F6we 08oWh2DnC4AXKbP+kuD9ZP6+5+x1H1zEzsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCgh Cj/CA/lc/LMthqQ773gauB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseB fDXHA6m4B3mUTWo13nid0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts 6TZ+IrPOwT1hfB4WNC+X2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiu Qmt3yqrmN63V9wzaPhC+xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKB Tccu2AXJXWAE1Xjh6GOC8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvF FFyAS0Nk1q/7EChPcbRbhJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh 2YmnmLRTro6eZ/qYwWkCu8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRk F3TwgucpyPtcpmQtTkWSgDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0L LH63+BrrHasfJzxKXzqgrW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4v q7oFCPsOgwARAQABwsF8BBgBCAAmAhsMFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAmic2qsF CSZYCKEACgkQTd4Q9wD/g1oq0xAAsAnw/OmsERdtdwRfAMpC74/++2wh9RvVQ0x8xXvoGJwZ rk0Jmck1ABIM//5sWDo7eDHk1uEcc95pbP9XGU6ZgeiQeh06+0vRYILwDk8Q/y06TrTb1n4n 7FRwyskKU1UWnNW86lvWUJuGPABXjrkfL41RJttSJHF3M1C0u2BnM5VnDuPFQKzhRRktBMK4 GkWBvXlsHFhn8Ev0xvPE/G99RAg9ufNAxyq2lSzbUIwrY918KHlziBKwNyLoPn9kgHD3hRBa Yakz87WKUZd17ZnPMZiXriCWZxwPx7zs6cSAqcfcVucmdPiIlyG1K/HIk2LX63T6oO2Libzz 7/0i4+oIpvpK2X6zZ2cu0k2uNcEYm2xAb+xGmqwnPnHX/ac8lJEyzH3lh+pt2slI4VcPNnz+ vzYeBAS1S+VJc1pcJr3l7PRSQ4bv5sObZvezRdqEFB4tUIfSbDdEBCCvvEMBgoisDB8ceYxO cFAM8nBWrEmNU2vvIGJzjJ/NVYYIY0TgOc5bS9wh6jKHL2+chrfDW5neLJjY2x3snF8q7U9G EIbBfNHDlOV8SyhEjtX0DyKxQKioTYPOHcW9gdV5fhSz5tEv+ipqt4kIgWqBgzK8ePtDTqRM qZq457g1/SXSoSQi4jN+gsneqvlTJdzaEu1bJP0iv6ViVf15+qHuY5iojCz8fa0= In-Reply-To: <219f7be4-8355-4376-bf97-3410c6e23867@lucifer.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: setgzokeku1zxqpc18yhk5uds6fw6cf3 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 17E29180017 X-Rspam-User: X-HE-Tag: 1768494845-21991 X-HE-Meta: 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 01ZFNIkl Avfp/VfwO0aANk+s= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 1/15/26 14:55, Lorenzo Stoakes wrote: > On Thu, Jan 15, 2026 at 10:20:12AM +0100, David Hildenbrand (Red Hat) wrote: >> Let's make it consistent with the naming of the files but also with the >> naming of CONFIG_BALLOON_MIGRATION. >> >> While at it, add a "/* CONFIG_BALLOON */". > > Probably not relevant but cheap for me to share :) so grepped for > 'memory_balloon' and saw: > > include/uapi/linux/virtio_ids.h > 44:#define VIRTIO_ID_MEMORY_BALLOON 13 /* virtio memory balloon */ > > This maybe relevant (I guess this isn't actually used anywhere?) though > interesting there is also VIRTIO_ID_BALLOON... hmm :) Yeah, we want to leave the virtio stuff alone. Now you'll learn something you probably wish you wouldn't know: As you spotted, there is #define VIRTIO_ID_BALLOON 5 /* virtio balloon */ And #define VIRTIO_ID_MEMORY_BALLOON 13 /* virtio memory balloon */ The virtio-spec [1] defines ID 5 to be the "Traditional Memory Balloon Device". And in there, we document that "This is the traditional balloon device. The device number 13 is reserved for a new memory balloon interface, with different semantics, which is expected in a future version of the standard. " That's in the spec already like, forever. Likely, at some point someone wanted to implement a new version (for whatever reason) and defined ID 13. But that never happened. So now we have these beautiful two device IDs. I'll note that the spec also defines a "DEVICE ID of Virtio Cpu balloon device as 47". But no changes really happened in the spec with that for the last two years (only the id is reserved). [1] https://docs.oasis-open.org/virtio/virtio/v1.4/virtio-v1.4.html#x1-4260001 -- Cheers David