mm: shrinkers: add scan interface for shrinker debugfs

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Add a scan interface which allows to trigger scanning of a particular
shrinker and specify memcg and numa node.  It's useful for testing,
debugging and profiling of a specific scan_objects() callback.  Unlike
alternatives (creating a real memory pressure and dropping caches via
/proc/sys/vm/drop_caches) this interface allows to interact with only one
shrinker at once.  Also, if a shrinker is misreporting the number of
objects (as some do), it doesn't affect scanning.

[roman.gushchin@linux.dev: improve typing, fix arg count checking]
  Link: https://lkml.kernel.org/r/YpgKttTowT22mKPQ@carbon
[akpm@linux-foundation.org: fix arg count checking]
Link: https://lkml.kernel.org/r/20220601032227.4076670-7-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

...

This commit is contained in:

Roman Gushchin 2022-05-31 20:22:27 -07:00 • committed by akpm

parent d261ea2353

commit bbf535fd6f

2 changed files with 109 additions and 4 deletions

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39

Documentation/admin-guide/mm/shrinker_debugfs.rst

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74

mm/shrinker_debug.c

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