mm/gup: local lru_add_drain() to avoid lru_add_drain_all()

In many cases, if collect_longterm_unpinnable_folios() does need to drain
the LRU cache to release a reference, the cache in question is on this
same CPU, and much more efficiently drained by a preliminary local
lru_add_drain(), than the later cross-CPU lru_add_drain_all().

Marked for stable, to counter the increase in lru_add_drain_all()s from
"mm/gup: check ref_count instead of lru before migration".  Note for clean
backports: can take 6.16 commit a03db236aebf ("gup: optimize longterm
pin_user_pages() for large folio") first.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Hugh Dickins <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
Cc: Axel Rasmussen <[email protected]>
Cc: Chris Li <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Keir Fraser <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Li Zhe <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Shivank Garg <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Wei Xu <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: yangge <[email protected]>
Cc: Yuanchu Xie <[email protected]>
Cc: Yu Zhao <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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