Commit 62376251 authored by Committed by Linus TorvaldsBrowse files
revert "mm: vmscan: do not swap anon pages just because free+file is low"
This reverts commit 0bf1457f ("mm: vmscan: do not swap anon pages just because free+file is low") because it introduced a regression in mostly-anonymous workloads, where reclaim would become ineffective and trap every allocating task in direct reclaim. The problem is that there is a runaway feedback loop in the scan balance between file and anon, where the balance tips heavily towards a tiny thrashing file LRU and anonymous pages are no longer being looked at. The commit in question removed the safe guard that would detect such situations and respond with forced anonymous reclaim. This commit was part of a series to fix premature swapping in loads with relatively little cache, and while it made a small difference, the cure is obviously worse than the disease. Revert it. Signed-off-by: Johannes Weiner <email@example.com> Reported-by: Christian Borntraeger <firstname.lastname@example.org> Acked-by: Christian Borntraeger <email@example.com> Acked-by: Rafael Aquini <firstname.lastname@example.org> Cc: Rik van Riel <email@example.com> Cc: <firstname.lastname@example.org> [3.12+] Signed-off-by: Andrew Morton <email@example.com> Signed-off-by: Linus Torvalds <firstname.lastname@example.org>
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