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mm: mglru: promote mapped executable folios after first usage

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Classical LRU protects mapped executable file folios through commit
8cab4754d2 ("vmscan: make mapped executable pages the first class
citizen") and commit c909e99364 ("vmscan: activate executable pages
after first usage"), giving executable code a better chance to stay in
memory, avoiding IO thrashing and improving workload performance.

However, MGLRU's protection of mapped executable file folios is less
reliable.  Although shrink_folio_list() checks references, the access flag
of mapped executable file folios may have already been checked and cleared
by lru_gen_look_around() or walk_mm().  Additionally, folio_update_gen()
or lru_gen_set_refs() only sets the 'PG_referenced' flag for mapped
executable file folios, which causes shrink_folio_list() to ignore the
first usage of these mapped executable file folios and reclaim them
easily.

Follow the classical LRU's logic, promoting mapped executable file folios
after their first usage in folio_update_gen() and lru_gen_set_refs(),
giving executable code a better chance to stay in memory.

On my 32-core Arm machine, with the memcg limit set to 2G, running 'make
-j32' to build kernel showed some improvement in sys time.

base			patched
9248.543s		7861.579s

Link: https://lore.kernel.org/f57d94b1d85bb3d620d89bb739128f0d929bf9c6.1784509721.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Harry Yoo <harry@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Baolin Wang 2026-07-20 19:12:02 +08:00 • committed by Andrew Morton
commit 0ee06ee38a
1 changed files with 27 additions and 16 deletions
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