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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 635BDC3ABC3 for ; Tue, 13 May 2025 10:24:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8B04A6B00C7; Tue, 13 May 2025 06:24:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 85CB56B00C8; Tue, 13 May 2025 06:24:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6FE096B00D2; Tue, 13 May 2025 06:24:35 -0400 (EDT) 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 4E6816B00C7 for ; Tue, 13 May 2025 06:24:35 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 4FE4FE086C for ; 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s=arc-20220608; t=1747131874; 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: in-reply-to:in-reply-to:references:references; bh=UjKvF8c19HlzT4fnjGs2zdhe7qKSeGFFOawZA9bws7o=; b=Efz3diUnydukXmC+nweyK4BuyiWTalfenVJi2PqAiojVLBRsgtYurVUgl8hJOFiHXHOFcQ SHsttcPmR/MNtGDwrsX0WRsTnRpfcYoEnplkO8kH3alcvsW9mJ6NqP7xe8rObw4r3wBTZu V3hPE5APzolgZlHRS3BqmRmZ5dMh4+A= X-AuditID: a67dfc5b-669ff7000002311f-85-68231de074e2 Date: Tue, 13 May 2025 19:24:27 +0900 From: Byungchul Park To: Matthew Wilcox Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel_team@skhynix.com, kuba@kernel.org, almasrymina@google.com, ilias.apalodimas@linaro.org, harry.yoo@oracle.com, hawk@kernel.org, akpm@linux-foundation.org, ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, john.fastabend@gmail.com, andrew+netdev@lunn.ch, edumazet@google.com, pabeni@redhat.com, vishal.moola@gmail.com Subject: Re: [RFC 19/19] mm, netmem: remove the page pool members in struct page Message-ID: <20250513102427.GA17155@system.software.com> References: <20250509115126.63190-1-byungchul@sk.com> <20250509115126.63190-20-byungchul@sk.com> <20250512125103.GC45370@system.software.com> <20250513014200.GA577@system.software.com> MIME-Version: 1.0 Content-Type: text/plain; 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That's why I think the place holder > > is necessary until it completely gets separated so as to have its own > > instance. > > We could tighten up the assert a bit. eg > > static_assert(sizeof(struct netmem_desc) <= offsetof(struct page, _refcount)); This mitigates what I concern. I will replace the place holder with this (but it must never happen to relocate the fields in struct page by any chance for any reason until the day. I trust you :). Byungchul > We _can't_ shrink struct page until struct folio is dynamically > allocated. The same patch series that dynamically allocates folio will > do the same for netmem and slab and ptdesc and ...