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Mercier" , "sumit.semwal@linaro.org" , "daniel.vetter@ffwll.ch" , "akpm@linux-foundation.org" , "hannes@cmpxchg.org" , "mhocko@kernel.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "jaewon31.kim@gmail.com" Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 9BA4318001B X-Stat-Signature: 4w54re1jsww3mmiqjcms6tffuj69peio X-HE-Tag: 1675788980-103243 X-HE-Meta: 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 hAQNfhC1 Ggi/4DhOxS9OM4fwcKeXVggizRu42FETgdQsHkad7yo1Zv2gFV1FrKVlwXtTSF/IieOJTP7tvYjMn+cFHWHRF2iZSqvRiZWYZ8AmQLia+yDxhTReY9QE0LTAT9o527QyKQqM1iIeCYug+UzNel3J03rR0pq4FwuUpkaCu3jczsToZp0p0ar5bvGcgu0idtvi0kt4/Pr36Bz9BzMfHp0uJM8wio3MFre+/lky2pEC1J40JSRPdoNRQVXoDzF1CjNVLDDeu/2LYGFCu6quqpg1XEmXVkP5UgKo6172U9dlgS4IXZSvLkABIuSXi0UH87T1273ZIF1B+tw9Zj6tHdSXffIaJzZOWqwXREoiWTq22obQiAxmuMcuGjGa19Z54DjbkIHzabTdd5jVPjxssq6QSaF1yl+KsLG6HJQ0RbJJpvtzsDwk= 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 Mon, Feb 6, 2023 at 11:33 PM Jaewon Kim wrote: > >I don't mean to discourage you, especially after all the effort here. > > > >Do you think evaluating the before and after impact to buffer usage > > > >(not just allocation) would be doable in the near term? > > > > Hello sorry but I don't have expertise on iommu. Actually I'm also wondering > all IOMMU can use order 4 free pages, if they are allocated. I am not sure > but I remember I heard order 9 (2MB) could be used, but I don't know about order 8 4. > > I guess IOMMU mmap also be same patern like we expect. I mean if order 4 is > prepared it could be faster like 1 to 4 times. But it, I think, should NOT be > that much slow even though the entire free memory is prepared as order 0 pages. > > > > > > >If you don't think so, given the benefit to allocation under pressure > > > >is large (and I don't mean to give you hurdles to jump), I'm willing > > > >to ack your change to get it merged, but if we later see performance > > > >trouble, I'll be quick to advocate for reverting it. Is that ok? > > > > Yes sure. I also want to know if it is. Ok. Please resend your latest patch and I'll go ahead and ack it and we'll watch. Thanks again for your efforts here! -john