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ae64f07a6a
memcg_list_lru_alloc() is called every time an object that may end up on the list_lru is created. It needs to quickly check if the list_lru heads for the memcg already exist, and allocate them when they don't. Doing this with folio objects is tricky: folio_memcg() is not stable and requires either RCU protection or pinning the cgroup. But it's desirable to make the existence check lightweight under RCU, and only pin the memcg when we need to allocate list_lru heads and may block. In preparation for switching the THP shrinker to list_lru, add a helper function for allocating list_lru heads coming from a folio. Link: https://lore.kernel.org/20260527204757.2544958-8-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Kairui Song <ryncsn@gmail.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam R. Howlett <liam@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mikhail Zaslonko <zaslonko@linux.ibm.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nico Pache <npache@redhat.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
359 lines
12 KiB
359 lines
12 KiB