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dkim=pass header.d=Nvidia.com header.s=selector2 header.b=m4Da4TnG; dmarc=pass (policy=reject) header.from=nvidia.com; spf=pass (imf23.hostedemail.com: domain of jgg@nvidia.com designates 40.107.94.62 as permitted sender) smtp.mailfrom=jgg@nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") X-HE-Tag: 1662048760-825837 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, Sep 01, 2022 at 09:21:19AM +0200, David Hildenbrand wrote: > commit 4b471e8898c3 ("mm, thp: remove infrastructure for handling splitting > PMDs") didn't remove all details about the THP split requirements for > RCU GUP-fast. > > IPI broeadcasts on THP split are no longer required. > > Cc: Kirill A. Shutemov > Cc: Sasha Levin > Cc: Aneesh Kumar K.V > Cc: Vlastimil Babka > Cc: Jerome Marchand > Cc: Andrea Arcangeli > Cc: Hugh Dickins > Cc: Jason Gunthorpe > Cc: John Hubbard > Cc: Peter Xu > Cc: Yang Shi > Signed-off-by: David Hildenbrand > --- > mm/gup.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) The comment a bit above seems to need touching to: * protected from page table pages being freed from under it, and should * block any THP splits. What is the current situation for THP splits anyhow? Is there are comment in the fast pmd code explaining it? But this seems OK too Reviewed-by: Jason Gunthorpe Jason