Revert "mm/compaction: fix set skip in fast_find_migrateblock"
commit
254f2c2056f3dab844dd808be89f459f69363129 upstream.
This reverts commit
466fb3775920e632121f555c8656756ff0f11c9b.
We have got openSUSE reports (Link 1) for 6.1 kernel with khugepaged
stalling CPU for long periods of time. Investigation of tracepoint data
shows that compaction is stuck in repeating fast_find_migrateblock()
based migrate page isolation, and then fails to migrate all isolated
pages.
Commit
466fb3775920 ("mm/compaction: fix set skip in fast_find_migrateblock")
was suspected as it was merged in 6.1 and in theory can indeed remove a
termination condition for fast_find_migrateblock() under certain
conditions, as it removes a place that always marks a scanned pageblock
from being re-scanned. There are other such places, but those can be
skipped under certain conditions, which seems to match the tracepoint
data.
Testing of revert also appears to have resolved the issue, thus revert
the commit until a more robust solution for the original problem is
developed.
It's also likely this will fix qemu stalls with 6.1 kernel reported in
Link 2, but that is not yet confirmed.
Link: https://bugzilla.suse.com/show_bug.cgi?id=1206848
Link: https://lore.kernel.org/kvm/b8017e09-f336-3035-8344-c549086c2340@kernel.org/
Link: https://lore.kernel.org/lkml/20230125134434.18017-1-mgorman@techsingularity.net/
Fixes: 466fb3775920 ("mm/compaction: fix set skip in fast_find_migrateblock")
Cc: <stable@vger.kernel.org>
Tested-by: Pedro Falcato <pedro.falcato@gmail.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>