#include <stdio.h>
+#include <unistd.h>
#include <linux/kthread.h>
#include <linux/list.h>
static LIST_HEAD(shrinker_list);
static DEFINE_MUTEX(shrinker_lock);
-int register_shrinker(struct shrinker *shrinker, const char *fmt, ...)
+void shrinker_free(struct shrinker *s)
{
- mutex_lock(&shrinker_lock);
- list_add_tail(&shrinker->list, &shrinker_list);
- mutex_unlock(&shrinker_lock);
- return 0;
-}
-
-void unregister_shrinker(struct shrinker *shrinker)
-{
- mutex_lock(&shrinker_lock);
- list_del(&shrinker->list);
- mutex_unlock(&shrinker_lock);
+ if (s->list.next) {
+ mutex_lock(&shrinker_lock);
+ list_del(&s->list);
+ mutex_unlock(&shrinker_lock);
+ }
+ free(s);
}
-struct meminfo {
- u64 total;
- u64 available;
-};
-
-static u64 parse_meminfo_line(const char *line)
+struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...)
{
- u64 v;
-
- if (sscanf(line, " %llu kB", &v) < 1)
- die("sscanf error");
- return v << 10;
+ return calloc(sizeof(struct shrinker), 1);
}
-void si_meminfo(struct sysinfo *val)
+int shrinker_register(struct shrinker *shrinker)
{
- size_t len, n = 0;
- char *line = NULL;
- const char *v;
- FILE *f;
-
- memset(val, 0, sizeof(*val));
- val->mem_unit = 1;
-
- f = fopen("/proc/meminfo", "r");
- if (!f)
- return;
-
- while ((len = getline(&line, &n, f)) != -1) {
- if ((v = strcmp_prefix(line, "MemTotal:")))
- val->totalram = parse_meminfo_line(v);
-
- if ((v = strcmp_prefix(line, "MemAvailable:")))
- val->freeram = parse_meminfo_line(v);
- }
-
- fclose(f);
- free(line);
+ mutex_lock(&shrinker_lock);
+ list_add_tail(&shrinker->list, &shrinker_list);
+ mutex_unlock(&shrinker_lock);
+ return 0;
}
static void run_shrinkers_allocation_failed(gfp_t gfp_mask)
si_meminfo(&info);
- if (info.totalram && info.freeram) {
- want_shrink = (info.totalram >> 2) - info.freeram;
-
- if (want_shrink <= 0)
- return;
- } else {
- /* If we weren't able to read /proc/meminfo, we must be pretty
- * low: */
-
- want_shrink = 8 << 20;
- }
+ /* Aim for 6% of physical RAM free without anything in swap */
+ want_shrink = (info.totalram >> 4) - info.freeram
+ + info.totalswap - info.freeswap;
+ if (want_shrink <= 0)
+ return;
mutex_lock(&shrinker_lock);
list_for_each_entry(shrinker, &shrinker_list, list) {
BUG_ON(IS_ERR(shrinker_task));
}
+#if 0
+/*
+ * We seem to be hitting a rare segfault when shutting down the shrinker thread.
+ * Disabling this is going to cause some harmless warnings about memory leaks:
+ */
__attribute__((destructor(103)))
static void shrinker_thread_exit(void)
{
shrinker_task = NULL;
}
+#endif