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| author | Roman Gushchin <roman.gushchin@linux.dev> | 2022-06-01 05:22:23 +0200 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-07-04 03:08:40 +0200 |
| commit | 5035ebc644aec92d55d1bbfe042f35341e4bffb5 (patch) | |
| tree | b6b76cac588da2cb4f7e17761fc8f508bef80051 /lib | |
| parent | mm: memcontrol: introduce mem_cgroup_ino() and mem_cgroup_get_from_ino() (diff) | |
| download | linux-5035ebc644aec92d55d1bbfe042f35341e4bffb5.tar.xz linux-5035ebc644aec92d55d1bbfe042f35341e4bffb5.zip | |
mm: shrinkers: introduce debugfs interface for memory shrinkers
This commit introduces the /sys/kernel/debug/shrinker debugfs interface
which provides an ability to observe the state of individual kernel memory
shrinkers.
Because the feature adds some memory overhead (which shouldn't be large
unless there is a huge amount of registered shrinkers), it's guarded by a
config option (enabled by default).
This commit introduces the "count" interface for each shrinker registered
in the system.
The output is in the following format:
<cgroup inode id> <nr of objects on node 0> <nr of objects on node 1>...
<cgroup inode id> <nr of objects on node 0> <nr of objects on node 1>...
...
To reduce the size of output on machines with many thousands cgroups, if
the total number of objects on all nodes is 0, the line is omitted.
If the shrinker is not memcg-aware or CONFIG_MEMCG is off, 0 is printed as
cgroup inode id. If the shrinker is not numa-aware, 0's are printed for
all nodes except the first one.
This commit gives debugfs entries simple numeric names, which are not very
convenient. The following commit in the series will provide shrinkers
with more meaningful names.
[akpm@linux-foundation.org: remove WARN_ON_ONCE(), per Roman]
Reported-by: syzbot+300d27c79fe6d4cbcc39@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/20220601032227.4076670-3-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 2e24db4bff19..0b483a8da409 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -699,6 +699,15 @@ config DEBUG_OBJECTS_ENABLE_DEFAULT help Debug objects boot parameter default value +config SHRINKER_DEBUG + default y + bool "Enable shrinker debugging support" + depends on DEBUG_FS + help + Say Y to enable the shrinker debugfs interface which provides + visibility into the kernel memory shrinkers subsystem. + Disable it to avoid an extra memory footprint. + config HAVE_DEBUG_KMEMLEAK bool |