4 #include <linux/list.h>
6 #include <linux/mutex.h>
7 #include <linux/shrinker.h>
9 #include "tools-util.h"
11 static LIST_HEAD(shrinker_list);
12 static DEFINE_MUTEX(shrinker_lock);
14 int register_shrinker(struct shrinker *shrinker, const char *fmt, ...)
16 mutex_lock(&shrinker_lock);
17 list_add_tail(&shrinker->list, &shrinker_list);
18 mutex_unlock(&shrinker_lock);
22 void unregister_shrinker(struct shrinker *shrinker)
24 mutex_lock(&shrinker_lock);
25 list_del(&shrinker->list);
26 mutex_unlock(&shrinker_lock);
34 static u64 parse_meminfo_line(const char *line)
38 if (sscanf(line, " %llu kB", &v) < 1)
43 void si_meminfo(struct sysinfo *val)
50 memset(val, 0, sizeof(*val));
53 f = fopen("/proc/meminfo", "r");
57 while ((len = getline(&line, &n, f)) != -1) {
58 if ((v = strcmp_prefix(line, "MemTotal:")))
59 val->totalram = parse_meminfo_line(v);
61 if ((v = strcmp_prefix(line, "MemAvailable:")))
62 val->freeram = parse_meminfo_line(v);
69 static void run_shrinkers_allocation_failed(gfp_t gfp_mask)
71 struct shrinker *shrinker;
73 mutex_lock(&shrinker_lock);
74 list_for_each_entry(shrinker, &shrinker_list, list) {
75 struct shrink_control sc = { .gfp_mask = gfp_mask, };
77 unsigned long have = shrinker->count_objects(shrinker, &sc);
79 sc.nr_to_scan = have / 8;
81 shrinker->scan_objects(shrinker, &sc);
83 mutex_unlock(&shrinker_lock);
86 void run_shrinkers(gfp_t gfp_mask, bool allocation_failed)
88 struct shrinker *shrinker;
92 if (!(gfp_mask & GFP_KERNEL))
95 /* Fast out if there are no shrinkers to run. */
96 if (list_empty(&shrinker_list))
99 if (allocation_failed) {
100 run_shrinkers_allocation_failed(gfp_mask);
106 if (info.totalram && info.freeram) {
107 want_shrink = (info.totalram >> 2) - info.freeram;
109 if (want_shrink <= 0)
112 /* If we weren't able to read /proc/meminfo, we must be pretty
115 want_shrink = 8 << 20;
118 mutex_lock(&shrinker_lock);
119 list_for_each_entry(shrinker, &shrinker_list, list) {
120 struct shrink_control sc = {
121 .gfp_mask = gfp_mask,
122 .nr_to_scan = want_shrink >> PAGE_SHIFT
125 shrinker->scan_objects(shrinker, &sc);
127 mutex_unlock(&shrinker_lock);