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Howlett" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, willy@infradead.org, mcgrof@kernel.org, gost.dev@samsung.com, Pankaj Raghav Subject: Re: [PATCH] huge_memory: return -EINVAL in folio split functions when THP is disabled Message-ID: References: <20250902084036.208921-1-kernel@pankajraghav.com> <90cd5be7-cbe6-42c5-b0eb-bf9613047097@pankajraghav.com> <6l6f5idkqebpai6qn6n3phbnydz55typdwmvp3eexwnhk4qr54@otcgssegyqke> <519df8fd-b02d-4b4b-bf47-79070e3d2c9e@pankajraghav.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: gu7isfzuku8it53erjoptby7bmpccg3n X-Rspam-User: X-Rspamd-Queue-Id: 8153D80013 X-Rspamd-Server: rspam01 X-HE-Tag: 1756820464-59128 X-HE-Meta: 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 whpIWClw RAR4wHPG/QCYoEU6nCI6qq2Mty9xEEL0sW0grH8wEg+0sIYiM62MhK/k3gaVRA4jZ2UBFoSt/UjJdS5Lk6g1rbSF0vFanufchL/V2IdEMQ7uNiykJq9J9HXOE8x1kfi01NR7ozYIIh0ugvLIPQ7ND9SLS/1qa9z0voXMpvXIwmKCwmNeo5hqkcgeK9SCotIzDb4QSsVQQ77ZTAwO8Eft6hLEMzss2O6JHoXLp1qE+XUn4MEkuV4oqwT9CCGGo8cRVLMT0ZF65K6WpUkaFHygIOwlS1Tlasp1pmDNv585bYPW7xFKpVeQlGqQhuQRhzhSe3gpUBXVBcOi4bN66Mkjl8yddL/ioV3c3JjDsrOprz3rInoX2JQt4v/MxBlxWGG6sTdcr 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: > > > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > > index 48c4f91c5b13..4ddf9e87db91 100644 > > --- a/include/linux/huge_mm.h > > +++ b/include/linux/huge_mm.h > > @@ -588,21 +588,29 @@ static inline int > > split_huge_page_to_list_to_order(struct page *page, struct list_head *list, > > unsigned int new_order) > > { > > + struct folio *folio = page_folio(page); > > + > > + VM_WARN_ON_ONCE_FOLIO(!folio_test_large(folio), folio); > > No. Make it unconditional. The point is we don't expect to see any > splitable folios, so no reason to get here at all. > Got it. Just one question though, in a future world where we remove the dependency between large folios and THP, then we can revert back this change to do a conditional WARN_ON? -- Pankaj