Revert "mm: skip CMA pages when they are not available"

This reverts commit 5da226dbfce3 ("mm: skip CMA pages when they are not
available") and b7108d66318a ("Multi-gen LRU: skip CMA pages when they are
not eligible").

lruvec->lru_lock is highly contended and is held when calling
isolate_lru_folios.  If the lru has a large number of CMA folios
consecutively, while the allocation type requested is not MIGRATE_MOVABLE,
isolate_lru_folios can hold the lock for a very long time while it skips
those.  For FIO workload, ~150million order=0 folios were skipped to
isolate a few ZONE_DMA folios [1].  This can cause lockups [1] and high
memory pressure for extended periods of time [2].

Remove skipping CMA for MGLRU as well, as it was introduced in sort_folio
for the same resaon as 5da226dbfce3a2f44978c2c7cf88166e69a6788b.

[1] https://lore.kernel.org/all/CAOUHufbkhMZYz20aM_3rHZ3OcK4m2puji2FGpUpn_-DevGk3Kg@mail.gmail.com/
[2] https://lore.kernel.org/all/[email protected]/

[[email protected]: also revert b7108d66318a, per Johannes]
  Link: https://lkml.kernel.org/r/[email protected]
  Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 5da226dbfce3 ("mm: skip CMA pages when they are not available")
Signed-off-by: Usama Arif <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: Bharata B Rao <[email protected]>
Cc: Breno Leitao <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Yu Zhao <[email protected]>
Cc: Zhaoyang Huang <[email protected]>
Cc: Zhaoyang Huang <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions