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[70.52.228.144]) by smtp.gmail.com with ESMTPSA id l16-20020a37f910000000b006ef1a8f1b81sm26439445qkj.5.2023.01.05.14.26.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Jan 2023 14:26:12 -0800 (PST) Date: Thu, 5 Jan 2023 17:26:10 -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 19/46] hugetlb: add HGM support for follow_hugetlb_page Message-ID: References: <20230105101844.1893104-1-jthoughton@google.com> <20230105101844.1893104-20-jthoughton@google.com> MIME-Version: 1.0 In-Reply-To: <20230105101844.1893104-20-jthoughton@google.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspam-User: X-Rspamd-Queue-Id: E92DC4000F X-Rspamd-Server: rspam01 X-Stat-Signature: tu4om47nht9crbb9wo4hjd5mftg3a8jq X-HE-Tag: 1672957575-701089 X-HE-Meta: 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 7ta5HnJ4 Sla7kTWGLoMigskd/418gDmfbNEBfdCBgESI6+Yvs1z7p545fKz0hKXHyVWh+f7K9lalYRWQ/acIvwZ2dENE8arZ9KmQqe0WpO1yWbfsiF5G1yjoEyWpCc36WAhTWttXA6hVgkcqcyiA18ZwxxylTvdqYIA9PjZUoVEtg 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 10:18:17AM +0000, James Houghton wrote: > @@ -6649,13 +6655,20 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, > */ > if (absent && (flags & FOLL_DUMP) && > !hugetlbfs_pagecache_present(h, vma, vaddr)) { > - if (pte) > + if (ptep) > spin_unlock(ptl); > hugetlb_vma_unlock_read(vma); > remainder = 0; > break; > } > > + if (!absent && pte_present(pte) && > + !hugetlb_pte_present_leaf(&hpte, pte)) { > + /* We raced with someone splitting the PTE, so retry. */ > + spin_unlock(ptl); vma unlock missing here. > + continue; > + } -- Peter Xu