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Wed, 16 Dec 2020 05:16:13 -0800 (PST) MIME-Version: 1.0 References: <20201213154534.54826-1-songmuchun@bytedance.com> <20201213154534.54826-4-songmuchun@bytedance.com> <20201216130602.GA29394@linux> In-Reply-To: <20201216130602.GA29394@linux> From: Muchun Song Date: Wed, 16 Dec 2020 21:15:37 +0800 Message-ID: Subject: Re: [External] Re: [PATCH v9 03/11] mm/hugetlb: Free the vmemmap pages associated with each HugeTLB page To: Oscar Salvador Cc: Jonathan Corbet , Mike Kravetz , Thomas Gleixner , mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, Peter Zijlstra , viro@zeniv.linux.org.uk, Andrew Morton , paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, Randy Dunlap , oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, Mina Almasry , David Rientjes , Matthew Wilcox , Michal Hocko , "Song Bao Hua (Barry Song)" , David Hildenbrand , Xiongchun duan , linux-doc@vger.kernel.org, LKML , Linux Memory Management List , linux-fsdevel Content-Type: text/plain; charset="UTF-8" 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: On Wed, Dec 16, 2020 at 9:06 PM Oscar Salvador wrote: > > 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. This approach will be more universal. :-) > 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? Yeah, you are right. I plan to reuse those interfaces in the feature. Thanks. > > > -- > Oscar Salvador > SUSE L3 -- Yours, Muchun