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t=1666642492; a=rsa-sha256; cv=fail; b=rnpsgZhYhcmr/pqzrbTyv6oanACuFihbV4yZlMJt1/hnmnDt/8DE517XOGmgQCtCnOINnh QGefHOARd1ZhDV1OyBVEbhcAulhGN3Z73ReTkdFRpFEkYC6NipKpzY1pb0MfF7ZgBF2Nw2 ChrCVuMeiPWR6TbqqCzigkKKuP/fAOo= Authentication-Results: imf30.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=l5qT8fsy; arc=reject ("signature check failed: fail, {[1] = sig:microsoft.com:reject}"); spf=pass (imf30.hostedemail.com: domain of dan.j.williams@intel.com designates 134.134.136.24 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (policy=none) header.from=intel.com X-Stat-Signature: bh66jq8chskrd3o7ux1ufd73881bpkzw X-Rspamd-Queue-Id: 80EAB80018 X-Rspamd-Server: rspam07 X-Rspam-User: X-HE-Tag: 1666642492-595440 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: Linus Torvalds wrote: > On Mon, Oct 24, 2022 at 12:39 PM Tim Chen wrote: > > > > I do think that the original locked page on migration problem was fixed > > by commit 9a1ea439b16b. Unfortunately the customer did not respond to > > us when we asked them to test their workload when that patch went > > into the mainline. > > Oh well. > > > I don't have objection to Matthew's fix to remove the bookmark code, > > now that it is causing problems with this scenario that I didn't > > anticipate in my original code. > > I'd really like to avoid *another* "we can't actually verify that this > helps" change in this area, so I'm hoping that the reporter that Dan > was talking to could test that patch. Oh, sorry, I had typed up that reply and contacted Tim offline, but forgot to send, now sent. > Otherwise we're kind of going back-and-forth based on "this might fix > things", which just feels really fragile and reminds me of the bad old > days when we had the "one step forward, two steps back" dance with > some of the suspend/resume issues. > > I realize that this code needs some extreme loads (and likely pretty > special hardware too) to actually become problematic, so testing is > _always_ going to be a bit of a problem, but still...