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[70.30.145.63]) by smtp.gmail.com with ESMTPSA id j20-20020a05620a289400b006fed58fc1a3sm9728529qkp.119.2023.01.11.13.51.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Jan 2023 13:51:38 -0800 (PST) Date: Wed, 11 Jan 2023 16:51:36 -0500 From: Peter Xu To: James Houghton Cc: Mike Kravetz , Muchun Song , David Hildenbrand , David Rientjes , Axel Rasmussen , Mina Almasry , Zach O'Keefe , Manish Mishra , Naoya Horiguchi , "Dr . David Alan Gilbert" , "Matthew Wilcox (Oracle)" , Vlastimil Babka , Baolin Wang , Miaohe Lin , Yang Shi , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 13/46] hugetlb: add hugetlb_hgm_walk and hugetlb_walk_step Message-ID: References: <20230105101844.1893104-1-jthoughton@google.com> <20230105101844.1893104-14-jthoughton@google.com> MIME-Version: 1.0 In-Reply-To: <20230105101844.1893104-14-jthoughton@google.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 5E9DD18000A X-Rspam-User: X-Stat-Signature: 385t6yj3iz5q4d46fuqpd7jgyi87jzcn X-HE-Tag: 1673473901-452719 X-HE-Meta: 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 SF+FWTBv b2DGjLn0S7RBfrpG1B1LXVmKSXzBOmHXIHPTS7ioq9swrIhBCqyOBbio6msZlE+fpwVQL+JfnWvoUm0DvPws8wCxPbdDoKD1SFnDbVjOC+I44wPcZi78CwdJDQ2WZ5k23YWiBTgFlTZN9Waf4WZydNhK6hQ== 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 Thu, Jan 05, 2023 at 10:18:11AM +0000, James Houghton wrote: [...] > +static int hugetlb_hgm_walk_uninit(struct hugetlb_pte *hpte, Nitpick on the name: the "uninit" can be misread into pairing with some other "init()" calls.. How about just call it hugetlb_hgm_walk (since it's the higher level API comparing to the existing one)? Then the existing hugetlb_hgm_walk can be called hugetlb_hgm_do_walk/__hugetlb_hgm_walk since it's one level down. > + pte_t *ptep, > + struct vm_area_struct *vma, > + unsigned long addr, > + unsigned long target_sz, > + bool alloc) > +{ > + struct hstate *h = hstate_vma(vma); > + > + hugetlb_pte_populate(vma->vm_mm, hpte, ptep, huge_page_shift(h), > + hpage_size_to_level(huge_page_size(h))); Another nitpick on name: I remembered we used to reach a consensus of using hugetlb_pte_init before? Can we still avoid the word "populate" (if "init" is not suitable since it can be updated during stepping, how about "setup")? [...] > +int hugetlb_walk_step(struct mm_struct *mm, struct hugetlb_pte *hpte, > + unsigned long addr, unsigned long sz) > +{ > + pte_t *ptep; > + spinlock_t *ptl; > + > + switch (hpte->level) { > + case HUGETLB_LEVEL_PUD: > + ptep = (pte_t *)hugetlb_alloc_pmd(mm, hpte, addr); > + if (IS_ERR(ptep)) > + return PTR_ERR(ptep); > + hugetlb_pte_populate(mm, hpte, ptep, PMD_SHIFT, > + HUGETLB_LEVEL_PMD); > + break; > + case HUGETLB_LEVEL_PMD: > + ptep = hugetlb_alloc_pte(mm, hpte, addr); > + if (IS_ERR(ptep)) > + return PTR_ERR(ptep); > + ptl = pte_lockptr(mm, (pmd_t *)hpte->ptep); > + __hugetlb_pte_populate(hpte, ptep, PAGE_SHIFT, > + HUGETLB_LEVEL_PTE, ptl); > + hpte->ptl = ptl; This line seems to be superfluous (even if benign). > + break; > + default: > + WARN_ONCE(1, "%s: got invalid level: %d (shift: %d)\n", > + __func__, hpte->level, hpte->shift); > + return -EINVAL; > + } > + return 0; > +} > + > /* > * Return a mask that can be used to update an address to the last huge > * page in a page table page mapping size. Used to skip non-present > -- > 2.39.0.314.g84b9a713c41-goog > -- Peter Xu