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 7C88CCCFA1E for ; Tue, 11 Nov 2025 01:41:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BC1C88E0007; Mon, 10 Nov 2025 20:41:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B4AE48E0002; Mon, 10 Nov 2025 20:41:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9EC2B8E0007; Mon, 10 Nov 2025 20:41:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 8789A8E0002 for ; Mon, 10 Nov 2025 20:41:06 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 0FC4414034A for ; 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imf20.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf20.hostedemail.com: domain of byungchul@sk.com designates 166.125.252.92 as permitted sender) smtp.mailfrom=byungchul@sk.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762825264; a=rsa-sha256; cv=none; b=DfNSvlMP2gazReUuWK9HUgnu55FhcnQZq47hhvmOgUPlMUY7/uWqRrlUy60zwZucq6ZRge 8bNmyRzGdpyz+k+1omV9d3dEYFo2mdrMcXAl+vYmxNej0AWMkQzfWM//p0buTd9OFz4KN8 E8oEUAcr1RvctqC95SUdCm9geV7NVZk= X-AuditID: a67dfc5b-c45ff70000001609-a1-691294292662 Date: Tue, 11 Nov 2025 10:40:52 +0900 From: Byungchul Park To: Jakub Kicinski Cc: linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel_team@skhynix.com, harry.yoo@oracle.com, ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, hawk@kernel.org, john.fastabend@gmail.com, sdf@fomichev.me, saeedm@nvidia.com, leon@kernel.org, tariqt@nvidia.com, mbloch@nvidia.com, andrew+netdev@lunn.ch, edumazet@google.com, pabeni@redhat.com, akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, horms@kernel.org, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, ilias.apalodimas@linaro.org, willy@infradead.org, brauner@kernel.org, kas@kernel.org, yuzhao@google.com, usamaarif642@gmail.com, baolin.wang@linux.alibaba.com, almasrymina@google.com, toke@redhat.com, asml.silence@gmail.com, bpf@vger.kernel.org, linux-rdma@vger.kernel.org, sfr@canb.auug.org.au, dw@davidwei.uk, ap420073@gmail.com, dtatulea@nvidia.com Subject: Re: [RFC mm v5 1/2] page_pool: check nmdesc->pp to see its usage as page pool for net_iov not page-backed Message-ID: <20251111014052.GA51630@system.software.com> References: <20251103075108.26437-1-byungchul@sk.com> <20251103075108.26437-2-byungchul@sk.com> <20251106173320.2f8e683a@kernel.org> <20251107015902.GA3021@system.software.com> <20251106180810.6b06f71a@kernel.org> <20251107044708.GA54407@system.software.com> <20251107174129.62a3f39c@kernel.org> <20251108022458.GA65163@system.software.com> <20251107183712.36228f2a@kernel.org> <20251110010926.GA70011@system.software.com> MIME-Version: 1.0 Content-Type: text/plain; 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Can we not move owner > > > > to _pp_mapping_pad ? Or reorder it with type, enum net_iov_type > > > > only has 2 values we can smoosh it with page_type easily. > > > > > > I'm still confused. I think you probably understand what this work is > > > for. (I've explained several times with related links.) Or am I > > > missing something from your questions? > > > > > > I've answered your question directly since you asked, but the point is > > > that, struct net_iov will no longer overlay on struct page. > > > > > > Instead, struct netmem_desc will be responsible for keeping the pp > > > fields while struct page will lay down the resonsibility, once the pp > > > fields will be removed from struct page like: > > > > I understand the end goal. I don't understand why patch 1 is a step > > in that direction, and you seem incapable of explaining it. So please > > either follow my suggestion on how to proceed with patch 2 without > > struct page and struct netmem_desc should keep difference information. > Even though they are sharing some fields at the moment, it should > eventually be decoupled, which I'm working on now. I'm removing the shared space between struct page and struct net_iov so as to make struct page look its own way to be shrinked and let struct net_iov be independent. Introduing a new shared space for page type is non-sense. Still not clear to you? Byungchul > > patch 1 in current form. Or come back when have the full conversion > > ready. > > This patch set represents the final phase of the full conversion process, > awaiting the next steps. Once this patch is completed, the entire > conversion will be finished, allowing for the final patch that removes > the pp fields from the struct page to be carried out. > > Byungchul