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([122.171.16.167]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82f8ebcc9easm7211169b3a.39.2026.04.18.10.18.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Apr 2026 10:18:14 -0700 (PDT) From: Sunny Patel To: david@kernel.org Cc: akpm@linux-foundation.org, apopple@nvidia.com, byungchul@sk.com, gourry@gourry.net, joshua.hahnjy@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, matthew.brost@intel.com, nueralspacetech@gmail.com, rakie.kim@sk.com, sj@kernel.org, ying.huang@linux.alibaba.com, ziy@nvidia.com Subject: Re: [PATCH] mm/migrate_device: Cleanup up PMD Checks and warnings Date: Sat, 18 Apr 2026 22:48:06 +0530 Message-ID: <20260418171806.11615-1-nueralspacetech@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <82193ab8-e6f6-4664-8b4f-e30d280d8b1c@kernel.org> References: <82193ab8-e6f6-4664-8b4f-e30d280d8b1c@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: ma13jwzpjf1aco5y4jhihmrkjjabon3h X-Rspam-User: X-Rspamd-Queue-Id: 6A83640004 X-Rspamd-Server: rspam05 X-HE-Tag: 1776532696-313754 X-HE-Meta: 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 yW2ptdeY 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/17/26 01:52, SeongJae Park wrote: > On Thu, 16 Apr 2026 21:44:15 +0200 "David Hildenbrand (Arm)" wrote: > >> On 4/14/26 16:13, Sunny Patel wrote: > [...] >>> @@ -865,12 +864,13 @@ static int migrate_vma_insert_huge_pmd_page(struct migrate_vma *migrate, >>> if (userfaultfd_missing(vma)) >>> goto unlock_abort; >>> >>> - if (!pmd_none(*pmdp)) { >>> + if (pmd_present(*pmdp)) { >>> if (!is_huge_zero_pmd(*pmdp)) >>> goto unlock_abort; >>> flush = true; >>> - } else if (!pmd_none(*pmdp)) >>> + } else if (!pmd_none(*pmdp)) { >>> goto unlock_abort; >>> + } >>> >>> add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); >>> folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE); >> >> is_huge_zero_pmd() checks pmd_present(), so we didn't have a bug before. >> >> We could also do: >> >> if (is_huge_zero_pmd(*pmdp)) { >> flush = true; >> } else if (!pmd_none(*pmdp)) { >> goto unlock_abort; >> } > > Then we could even further remove the braces and reduce one more line, nice! is_huge_zero_pmd() didn't check for pmd_present as of now as per the current implementation of it so additional check require for pmd_present(). Please let me know if anything needs to add in here. Thanks, Sunny Patel