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Howlett" , Ryan Roberts , Vlastimil Babka , Lance Yang , Frank van der Linden Subject: Re: [LSF/MM/BPF TOPIC] Beyond 2MB: Why Terabyte-Scale Machines Need 1GB Transparent Huge Pages Message-ID: References: <540c5c13-9cfb-44ea-b18f-8e4abff30a01@linux.dev> <3485c8c8-9bfc-4725-885a-626e79d0aebb@kernel.org> <87DAD8A6-85E7-4BC9-B81A-4A842DC546E3@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87DAD8A6-85E7-4BC9-B81A-4A842DC546E3@nvidia.com> X-Stat-Signature: ux7pbgk6aimmrtmwu5seqono7r5w77mh X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 9EC7EC0003 X-HE-Tag: 1771521208-566715 X-HE-Meta: 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 3q3fRkbx cRxZtG2SBCg2sYOvXF6yQT2gJa6ZwKvLK8zV63HQ7LFh6LPNIja439FB4Wl3VIlTiPlNhnZ7kolXH8SyK0aViDVvsHr3UP/EGq1LBHvTNGrUcG/G7InV0oyJV6gpyiPx28QUu/gSQnjidJeKTb+UDP4Wc8HfcpS9o5V5tnomUkux0G2Bz85tp2cAbr2tz/JhSRVUdpUnSrutA33NS+GDh0gl/1qTiwojEWuaMQWSTjTpTMdqu6/rnl7hhqwnbjDKVuOoF 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 Thu, Feb 19, 2026 at 11:49:27AM -0500, Zi Yan wrote: > If HW can support multiple TLB entries translating to the same physical frame > and allow translation priority of TLB entries, this remapping would be easy > and we can still keep the 1GB PUD mapping. Basically, we can have 1GB TLB entry > pointing to the 1GB folio and another 4KB TLB entry pointing to the remapped > region and overriding the part in the original 1GB vaddr region. Uh, do you know any hardware that supports that? Every CPU I'm familiar with has notes suggesting that trying to do this will cause you to Have A Very Bad Day.