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b=AEpkZEQ/28Jy9jamWpqXZLpluD48shx0eOD8NrIoAjEU9t1OZDyQMF1gA27e4+h5ISqTMc cgFuvKVeFWZQRJDTlyhF0lJ/DQTOYjKYeGJdieB/oh3vZK9ktUg1Bgm+50MueSj9jRWLUp TB3kcaZCAo+lULlUkj/Q1D4Rh3Rv4gM= X-Rspamd-Queue-Id: 054C64004D X-Rspam-User: Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=fb.com header.s=facebook header.b=BOQ8wXxc; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf04.hostedemail.com: domain of "prvs=0240d54e4f=alexlzhu@fb.com" designates 67.231.145.42 as permitted sender) smtp.mailfrom="prvs=0240d54e4f=alexlzhu@fb.com"; dmarc=pass (policy=reject) header.from=fb.com X-Rspamd-Server: rspam02 X-Stat-Signature: b684i6ced9b73cssc9wrzj6f8hhzxpfe X-HE-Tag: 1661806196-295460 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: > How stale could the information in the utilization bucket be? The staleness would be capped by the duration of the scan, 70s in in the=20 example. =20 > Is it possible that THP shrinker splits a THP used to have a lot of > zero-filled subpages but now have all subpages filled with useful > values? This is possible, but we free only the zero pages, which cannot have any useful values. How often it happens that THPs move utilization buckets= =20 should be workload dependent.=20 > In Patch 2, split_huge_page() only unmap zero-filled subpages, > but for THP shrinker, should it verify the utilization before it > splits the page? I think we should add this check to verify that it is still in the lowest b= ucket before having the shrinker split the page. The utilization could have changed and this way we= do not need to worry about workloads where THPs move utilization buckets. Thanks!= =20