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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: 7qhi3csbuyr7559x3zhfwfxayb9diq9t X-Rspam-User: X-Rspamd-Queue-Id: 03AFC4000D X-Rspamd-Server: rspam04 X-HE-Tag: 1759583517-553384 X-HE-Meta: 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 exyxhTy7 EfgoeZvT5A8rVKxxVRXsn5kRBAk1ojeJrMlJc4YMxsLwqFcQLOmxF3oDaj2I2wA8u02N98QPtNbaWxLrq51BfXCMA6NSqr01JrK3Q8NOyoQDO81UmxNNgo4TRdg8DSbgZj+g+Cl5y03+GFXklMFtMMipBWrKbIQlBKK8YGg7W8MirW8Sv1I28AvuGLS7Uaj9SQMqpn0YEOMr+XSM9b/Rklzmch2G97GTFnxvUwpSa+bnQR/U= 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: List-Subscribe: List-Unsubscribe: On 04/10/25 3:12 pm, Wei Yang wrote: > On Fri, Oct 03, 2025 at 10:35:12PM +0530, Dev Jain wrote: >> On 02/10/25 1:02 pm, Lance Yang wrote: >>> From: Lance Yang >>> >>> As David suggested, the PTE scanning logic in hpage_collapse_scan_pmd() >>> and __collapse_huge_page_isolate() was almost duplicated. >>> >>> This patch cleans things up by moving all the common PTE checking logic >>> into a new shared helper, thp_collapse_check_pte(). >>> >>> Suggested-by: David Hildenbrand >>> Signed-off-by: Lance Yang >>> --- >> In hpage_collapse_scan_pmd(), we enter with mmap lock held, so for > This is true for the first loop, but we will unlock/lock mmap and revalidate > vma before isolation. > >> an anonymous vma, is it even possible to hit if (!folio_test_anon(folio))? >> In which case we can replace this with VM_BUG_ON_FOLIO and abstract away >> till the folio_maybe_mapped_shared() block? > But it looks still valid, since hugepage_vma_revalidate() will check the vma > is still anonymous vma after grab the mmap lock again. > > My concern is would VM_BUG_ON_FOLIO() be too heavy? How about warn on and > return? Frankly I do not have much opinion on the BUG_ON/WARN_ON debate since I haven't properly understood that, but this BUG_ON is under CONFIG_DEBUG_VM anways. But if you want to change this to WARN then you can do it at both places. >