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See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: B919D20022 X-Stat-Signature: 8x7yt1kn3fb8fqjoctupn6p8o9m1ehu5 X-Rspam-User: X-HE-Tag: 1676282108-606308 X-HE-Meta: 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 JQgru6GS roficdMSFbtD7XYzylLcil6iywNOdtmjpbWq2L+i9VSci/IqBErPuCz/wHZlWfWLlUudJl2+GpgMagdihgODb0WN/zeROQob/vtg9KpXMDC+7eTIkR04l6FeZppsj6j0OFhQXhjDdLTxsM3T5A2D8LLMXJXlzHmaj0wop6OLbagCBV2ztOy48PaPlkoaka1jd57YLcLTSSHGQ7R+DYLsFCLVblP6fxVXyW61MG3EH3VgfkImh4D6H/7CxR+kgZg3v+q49Zl0qjBk429NXWrI8hRNpNe+rSpbl9HT2M1+hhCvduND+H+r/3wqZlo3gGE/Bp4FOsvlY65xwnybd0T9sEoOBKGcIOqHU4ePbsEJIQfxHr/9+iJ8E6QqjAM5AdQ5A9SY5WCimXCfRpH7fO0PBKsuq0Q== 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 Fri, Feb 10, 2023 at 12:29:54PM +0100, Jan Kara wrote: > functionally that would make sense but as I've mentioned in my reply to you > [1], the problem here is the performance. I've now dug out the discussion > from 2018 where John actually tried to take pinned pages out of the LRU [2] > and the result was 20% IOPS degradation on his NVME drive because of the > cost of taking the LRU lock. I'm not even speaking how costly that would > get on any heavily parallel direct IO workload on some high-iops device... I think we need to distinguish between short- and long terms pins. For short term pins like direct I/O it doesn't make sense to take them off the lru, or to do any other special action. Writeback will simplify have to wait for the short term pin. Long-term pins absolutely would make sense to be taken off the LRU list.