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See http://www.infradead.org/rpr.html X-Stat-Signature: zee8rgihorgxzq4xrdbe51ofgsmk1tc5 X-Rspamd-Queue-Id: 6A00120003 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1748966532-288515 X-HE-Meta: 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 7qm1qPfC 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 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 Tue, Jun 03, 2025 at 05:55:18PM +0200, Christian König wrote: > On 6/3/25 16:28, Christoph Hellwig wrote: > > On Tue, Jun 03, 2025 at 04:18:22PM +0200, Christian König wrote: > >>> Does it matter compared to the I/O in this case? > >> > >> It unfortunately does, see the numbers on patch 3 and 4. > > > > That's kinda weird. Why does the page table lookup tage so much > > time compared to normal I/O? > > I have absolutely no idea. It's rather surprising for me as well. > > The user seems to have a rather slow CPU paired with fast I/O, but it still looks rather fishy to me. > > Additional to that allocating memory through memfd_create() is *much* slower on that box than through dma-buf-heaps (which basically just uses GFP and an array). Can someone try to reproduce these results on a normal system before we're building infrastructure based on these numbers?