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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14275C2BBCD for ; Wed, 16 Dec 2020 13:06:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CF2A42339F for ; Wed, 16 Dec 2020 13:06:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726027AbgLPNGx (ORCPT ); Wed, 16 Dec 2020 08:06:53 -0500 Received: from mx2.suse.de ([195.135.220.15]:42356 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725879AbgLPNGx (ORCPT ); Wed, 16 Dec 2020 08:06:53 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3B785AC7B; Wed, 16 Dec 2020 13:06:11 +0000 (UTC) Date: Wed, 16 Dec 2020 14:06:07 +0100 From: Oscar Salvador To: Muchun Song Cc: corbet@lwn.net, mike.kravetz@oracle.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, rdunlap@infradead.org, oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, almasrymina@google.com, rientjes@google.com, willy@infradead.org, mhocko@suse.com, song.bao.hua@hisilicon.com, david@redhat.com, duanxiongchun@bytedance.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v9 03/11] mm/hugetlb: Free the vmemmap pages associated with each HugeTLB page Message-ID: <20201216130602.GA29394@linux> References: <20201213154534.54826-1-songmuchun@bytedance.com> <20201213154534.54826-4-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201213154534.54826-4-songmuchun@bytedance.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Sun, Dec 13, 2020 at 11:45:26PM +0800, Muchun Song wrote: > + > +/* > + * vmemmap_rmap_walk - walk vmemmap page table > + * > + * @rmap_pte: called for each non-empty PTE (lowest-level) entry. > + * @reuse: the page which is reused for the tail vmemmap pages. > + * @vmemmap_pages: the list head of the vmemmap pages that can be freed. > + */ > +struct vmemmap_rmap_walk { > + void (*rmap_pte)(pte_t *pte, unsigned long addr, > + struct vmemmap_rmap_walk *walk); > + struct page *reuse; > + struct list_head *vmemmap_pages; > +}; Why did you chose this approach in this version? Earlier versions of this patchset had a single vmemmap_to_pmd() function which returned the PMD, and now we have serveral vmemmap_{levels}_range and a vmemmap_rmap_walk. A brief explanation about why this change was introduced would have been nice. I guess it is because ealier versions were too oriented for the usecase this patchset presents, while the new versions tries to be more broad about future re-uses of the interface? -- Oscar Salvador SUSE L3