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b=EvIXvpzKVVjOwwTpybD1uSPUoLx6n3xoVIdmWsQG3W27VAdCTj5AQipNMzjCDsA0n TpaXtV9msRMvTnZQHkBfjIk7scNcAH+1p4HH90Wk9V7qdpbhN0TDAkKd4+xdvAgBpe SkuNE9P5MDxqhDr1u7YuNmIB5NMKNCLC/0/1DjIiuKHtfbvanebyms9Yu6q6XefFra 5xudcG0atI/nE4oV7YxTCC+HZG6pbT5IxwJYhMDHDp4utIIYqdthQ2GQHVWABv2AJT bpkqUD/JSVbNpzhnPlTmlGlmT9t8CDi+zUGRmHvnsNzmH145M5U5x1ZbtpXvj9iQwC aCSPZS0ZomZ/Q== From: SeongJae Park To: "David Hildenbrand (Arm)" Cc: SeongJae Park , Sunny Patel , Andrew Morton , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/migrate_device: Cleanup up PMD Checks and warnings Date: Thu, 16 Apr 2026 16:52:51 -0700 Message-ID: <20260416235252.58831-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 4FF0020008 X-Rspamd-Server: rspam07 X-Stat-Signature: 18gstay8xrf61rwbfojd7tk1xpjpn4p4 X-Rspam-User: X-HE-Tag: 1776383581-926524 X-HE-Meta: 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 qNW8YsVH cdnpa1qmoFH+SvMC9g5R2Vfr/8eJ7f4usQL9koQpvsFD/fKMMHjOCNh+oBmGKO/lzkk88JfCT9l9J7jY7bNOEPQygOlQ2geoc6kmUcb8IBYyOA5Qn3ECvNzBBP/ZvPCKXuhd69TPR8cUQvT2PtmOu+33vcLFjTK+DkLZm0SSQhfBtDnJrvFsyZ/vXeU+2Zjvw0GVI6wtTd/noCcG+31nBMH0Eq9X7fWQ9MzeTfrurdA0JeQeEn/ZEgzg4j6Tsah1wklKkL/MIguQoLzYAc/l9g4aFakidKVKDBc1fBKwbWtjmUu9uHSQ2AuCzZt1otJyeYRhOhbTaJNCAkw3G3PrXqhMzxksf2DqpluEVsx9J6Vb1dj4jcjUAYzw2+jKDQZBCF5FY Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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! Thanks, SJ [...]