mm/shrinker: allocate shrinker_info_unit from a dedicated kmem_cache

shrinker_info_unit holds BITS_PER_LONG atomic_long_t of deferred work plus
a one-word bitmap, 520 bytes on 64-bit.  kzalloc_node() takes it from
kmalloc-1k, so almost half of every unit is padding.

Allocate the units from a cache of their own, sized to the unit.  The
cache is not cache-line aligned: the counters of a unit already share
cache lines between shrinkers, and aligning the unit would only keep
neighbouring units off each other's boundary line, at the cost of part of
the saving.

Link: https://lore.kernel.org/20261019-vstor-144715-shrinker_info_unit-kmem_cache-v3-1-0fb061e09bf4@virtuozzo.com
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Harry Yoo (Meta) <harry@kernel.org>
Reviewed-by: Qi Zheng <qi.zheng@linux.dev>
Acked-by: Muchun Song <muchun.song@linux.dev>
Assisted-by: LLM
Cc: Dave Chinner <david@fromorbit.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>

0 files changed, 0 insertions, 0 deletions