From 5035ebc644aec92d55d1bbfe042f35341e4bffb5 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Tue, 31 May 2022 20:22:23 -0700 Subject: 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: ... ... ... 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 Reviewed-by: Kent Overstreet Acked-by: Muchun Song Cc: Christophe JAILLET Cc: Dave Chinner Cc: Hillf Danton Signed-off-by: Andrew Morton --- mm/Makefile | 1 + 1 file changed, 1 insertion(+) (limited to 'mm/Makefile') diff --git a/mm/Makefile b/mm/Makefile index 6f9ffa968a1a..9a564f836403 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -133,3 +133,4 @@ obj-$(CONFIG_PAGE_REPORTING) += page_reporting.o obj-$(CONFIG_IO_MAPPING) += io-mapping.o obj-$(CONFIG_HAVE_BOOTMEM_INFO_NODE) += bootmem_info.o obj-$(CONFIG_GENERIC_IOREMAP) += ioremap.o +obj-$(CONFIG_SHRINKER_DEBUG) += shrinker_debug.o -- cgit v1.2.3