#include <stdio.h>
+#include <unistd.h>
+#include <linux/kthread.h>
#include <linux/list.h>
+#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/shrinker.h>
static LIST_HEAD(shrinker_list);
static DEFINE_MUTEX(shrinker_lock);
-int register_shrinker(struct shrinker *shrinker, const char *fmt, ...)
+struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...)
+{
+ return calloc(sizeof(struct shrinker), 1);
+}
+
+int shrinker_register(struct shrinker *shrinker)
{
mutex_lock(&shrinker_lock);
list_add_tail(&shrinker->list, &shrinker_list);
u64 available;
};
-static u64 parse_meminfo_line(const char *line)
+void si_meminfo(struct sysinfo *val)
{
- u64 v;
+ long page_size = sysconf(_SC_PAGESIZE);
+ memset(val, 0, sizeof(*val));
+ val->mem_unit = 1;
- if (sscanf(line, " %llu kB", &v) < 1)
- die("sscanf error");
- return v << 10;
-}
-
-static struct meminfo read_meminfo(void)
-{
- struct meminfo ret = { 0 };
- size_t len, n = 0;
- char *line = NULL;
- const char *v;
- FILE *f;
-
- f = fopen("/proc/meminfo", "r");
- if (!f)
- return ret;
-
- while ((len = getline(&line, &n, f)) != -1) {
- if ((v = strcmp_prefix(line, "MemTotal:")))
- ret.total = parse_meminfo_line(v);
-
- if ((v = strcmp_prefix(line, "MemAvailable:")))
- ret.available = parse_meminfo_line(v);
- }
-
- fclose(f);
- free(line);
-
- return ret;
+ val->totalram = sysconf(_SC_PHYS_PAGES) * page_size;
+ val->freeram = sysconf(_SC_AVPHYS_PAGES) * page_size;
}
static void run_shrinkers_allocation_failed(gfp_t gfp_mask)
void run_shrinkers(gfp_t gfp_mask, bool allocation_failed)
{
struct shrinker *shrinker;
- struct meminfo info;
+ struct sysinfo info;
+ struct mallinfo2 malloc_info = mallinfo2();
s64 want_shrink;
+ if (!(gfp_mask & GFP_KERNEL))
+ return;
+
/* Fast out if there are no shrinkers to run. */
if (list_empty(&shrinker_list))
return;
return;
}
- info = read_meminfo();
+ si_meminfo(&info);
- if (info.total && info.available) {
- want_shrink = (info.total >> 2) - info.available;
+ if (info.totalram && info.totalram >> 4 < info.freeram) {
+ /* freeram goes up when system swaps, use malloced data instead */
+ want_shrink = -malloc_info.arena + (info.totalram / 10 * 8);
if (want_shrink <= 0)
return;
} else {
- /* If we weren't able to read /proc/meminfo, we must be pretty
- * low: */
-
- want_shrink = 8 << 20;
+ /* We want to play nice with other apps keep 6% avaliable, free 3% */
+ want_shrink = (info.totalram >> 5);
}
mutex_lock(&shrinker_lock);
}
mutex_unlock(&shrinker_lock);
}
+
+static int shrinker_thread(void *arg)
+{
+ while (!kthread_should_stop()) {
+ struct timespec to;
+ int v;
+
+ clock_gettime(CLOCK_MONOTONIC, &to);
+ to.tv_sec += 1;
+ __set_current_state(TASK_INTERRUPTIBLE);
+ errno = 0;
+ while ((v = READ_ONCE(current->state)) != TASK_RUNNING &&
+ errno != ETIMEDOUT)
+ futex(¤t->state, FUTEX_WAIT_BITSET|FUTEX_PRIVATE_FLAG,
+ v, &to, NULL, (uint32_t)~0);
+ if (kthread_should_stop())
+ break;
+ if (v != TASK_RUNNING)
+ __set_current_state(TASK_RUNNING);
+ run_shrinkers(GFP_KERNEL, false);
+ }
+
+ return 0;
+}
+
+struct task_struct *shrinker_task;
+
+__attribute__((constructor(103)))
+static void shrinker_thread_init(void)
+{
+ shrinker_task = kthread_run(shrinker_thread, NULL, "shrinkers");
+ BUG_ON(IS_ERR(shrinker_task));
+}
+
+__attribute__((destructor(103)))
+static void shrinker_thread_exit(void)
+{
+ int ret = kthread_stop(shrinker_task);
+ BUG_ON(ret);
+
+ shrinker_task = NULL;
+}