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charset=iso-8859-15 Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: cr6m67xsh6sdtao3fg6wcs3jfpeqay63 X-Rspamd-Queue-Id: AA80440013 X-HE-Tag: 1682523215-570725 X-HE-Meta: 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 e/5XTJWj RmqI1tDZrUMPcSxLngTcaCDRp0ypyInQvm8/q0mvew60IgfFXhk9oNuQk7j5fD6c85BYSoUvM+zHeEzNzWvmlwR1QmEXPZr3LWUQ4x0iItL++VB1UYqk0zYsmLhDQYc47pICbjNmNOb72hDTKj7uJshrl5SBI/Ft7EtPZcVxcuAED4BLb//tbSCyf3Gm9330BuMh8a4Wm6KiJDxeniRVEjXzAq1SoUTrrfJlg9VIEjS5YXGGRrpqx59eRwS224dc+Tb+KV1occiFujjm5XdcBXcV9Ug== 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 Wed, Apr 26, 2023 at 05:10:14PM +0200, Vlastimil Babka wrote: > On 4/26/23 17:03, Baolin Wang wrote: > > This reverts commit 95e7a450b8190673675836bfef236262ceff084a. > > > > When I tested thpscale with v6.3 kernel, I found the compaction efficiency > > had a great regression compared to v6.2-rc1 kernel. See below numbers: > > v6.2-rc v6.3 > > Percentage huge-3 81.35 ( 0.00%) 32.97 ( -59.47%) > > Percentage huge-5 89.92 ( 0.00%) 41.70 ( -53.63%) > > Percentage huge-7 92.41 ( 0.00%) 34.08 ( -63.12%) > > Percentage huge-12 90.29 ( 0.00%) 41.10 ( -54.49%) > > Percentage huge-18 82.38 ( 0.00%) 41.24 ( -49.95%) > > Percentage huge-24 80.34 ( 0.00%) 35.99 ( -55.20%) > > Percentage huge-30 88.90 ( 0.00%) 44.20 ( -50.28%) > > Percentage huge-32 90.69 ( 0.00%) 79.57 ( -12.25%) > > > > Ops Compaction stalls 113790.00 207099.00 > > Ops Compaction success 33983.00 19488.00 > > Ops Compaction failures 79807.00 187611.00 > > Ops Compaction efficiency 29.86 9.41 > > > > After some investigation, I found the commit 95e7a450b819 > > ("Revert mm/compaction: fix set skip in fast_find_migrateblock") caused > > the regression. This commit revert the commit 7efc3b726103 ("mm/compaction: > > fix set skip in fast_find_migrateblock") to fix a CPU stalling issue, which > > is caused by compaction stucked in repeating fast_find_migrateblock(). > > > > And now the compaction stalling issue is addressed by commit cfccd2e63e7e > > ("mm, compaction: finish pageblocks on complete migration failure"). So > > IIRC at that time I was pointing out some scenarios that could make the > problem appear even after that commit, and we wanted to revisit that > when Mel is back. > Yes, I've prototyped the fix against 6.3-rc7 and the revert is at the end but the revert on its own has the potential for causing problems. The series needs to be rebased, retested and posted. What I last tested should show up shortly at https://git.kernel.org/pub/scm/linux/kernel/git/mel/linux.git/ mm-follupfastmigrate-v1r1 -- Mel Gorman SUSE Labs