From d50b2ff1fec2d4de728e764d6420763692a761b0 Mon Sep 17 00:00:00 2001 From: Rebecca Schultz Zavin Date: Fri, 5 Oct 2012 13:54:59 -0700 Subject: [PATCH] mm: vmscan: Add a debug file for shrinkers This patch adds a debugfs file called "shrinker" when read this calls all the shrinkers in the system with nr_to_scan set to zero and prints the result. These results are the number of objects the shrinkers have available and can thus be used an indication of the total memory that would be availble to the system if a shrink occurred. Change-Id: Ied0ee7caff3d2fc1cb4bb839aaafee81b5b0b143 Signed-off-by: Rebecca Schultz Zavin --- mm/vmscan.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/mm/vmscan.c b/mm/vmscan.c index a9c74b409681..9f4cf9910ce3 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -174,6 +175,39 @@ static unsigned long get_lru_size(struct lruvec *lruvec, enum lru_list lru) return zone_page_state(lruvec_zone(lruvec), NR_LRU_BASE + lru); } +struct dentry *debug_file; + +static int debug_shrinker_show(struct seq_file *s, void *unused) +{ + struct shrinker *shrinker; + struct shrink_control sc; + + sc.gfp_mask = -1; + sc.nr_to_scan = 0; + + down_read(&shrinker_rwsem); + list_for_each_entry(shrinker, &shrinker_list, list) { + int num_objs; + + num_objs = shrinker->count_objects(shrinker, &sc); + seq_printf(s, "%pf %d\n", shrinker->scan_objects, num_objs); + } + up_read(&shrinker_rwsem); + return 0; +} + +static int debug_shrinker_open(struct inode *inode, struct file *file) +{ + return single_open(file, debug_shrinker_show, inode->i_private); +} + +static const struct file_operations debug_shrinker_fops = { + .open = debug_shrinker_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + /* * Add a shrinker callback to be called from the vm. */ @@ -203,6 +237,15 @@ int register_shrinker(struct shrinker *shrinker) } EXPORT_SYMBOL(register_shrinker); +static int __init add_shrinker_debug(void) +{ + debugfs_create_file("shrinker", 0644, NULL, NULL, + &debug_shrinker_fops); + return 0; +} + +late_initcall(add_shrinker_debug); + /* * Remove one */