Update bcachefs sources to 8fd009dd76 bcachefs: Rip out code for storing backpointers...

[bcachefs-tools-debian] / linux / shrinker.c

diff --git a/linux/shrinker.c b/linux/shrinker.c
index 7926be06e29f85983e331725877e351a56915680..0b5715b36a00ee210dfcd6b53c3e53d6e706b196 100644 (file)
--- a/linux/shrinker.c
+++ b/linux/shrinker.c
@@ -1,7 +1,9 @@
 
 #include <stdio.h>
 
+#include <linux/kthread.h>
 #include <linux/list.h>
+#include <linux/mm.h>
 #include <linux/mutex.h>
 #include <linux/shrinker.h>
 
@@ -10,7 +12,7 @@
 static LIST_HEAD(shrinker_list);
 static DEFINE_MUTEX(shrinker_lock);
 
-int register_shrinker(struct shrinker *shrinker)
+int register_shrinker(struct shrinker *shrinker, const char *fmt, ...)
 {
        mutex_lock(&shrinker_lock);
        list_add_tail(&shrinker->list, &shrinker_list);
@@ -28,7 +30,6 @@ void unregister_shrinker(struct shrinker *shrinker)
 struct meminfo {
        u64             total;
        u64             available;
-
 };
 
 static u64 parse_meminfo_line(const char *line)
@@ -40,55 +41,117 @@ static u64 parse_meminfo_line(const char *line)
        return v << 10;
 }
 
-static struct meminfo read_meminfo(void)
+void si_meminfo(struct sysinfo *val)
 {
-       struct meminfo ret = { 0 };
        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)
-               die("error opening /proc/meminfo: %m");
+               return;
 
        while ((len = getline(&line, &n, f)) != -1) {
                if ((v = strcmp_prefix(line, "MemTotal:")))
-                       ret.total = parse_meminfo_line(v);
+                       val->totalram = parse_meminfo_line(v);
 
                if ((v = strcmp_prefix(line, "MemAvailable:")))
-                       ret.available = parse_meminfo_line(v);
+                       val->freeram = parse_meminfo_line(v);
        }
 
        fclose(f);
        free(line);
+}
+
+static void run_shrinkers_allocation_failed(gfp_t gfp_mask)
+{
+       struct shrinker *shrinker;
+
+       mutex_lock(&shrinker_lock);
+       list_for_each_entry(shrinker, &shrinker_list, list) {
+               struct shrink_control sc = { .gfp_mask  = gfp_mask, };
 
-       return ret;
+               unsigned long have = shrinker->count_objects(shrinker, &sc);
+
+               sc.nr_to_scan = have / 8;
+
+               shrinker->scan_objects(shrinker, &sc);
+       }
+       mutex_unlock(&shrinker_lock);
 }
 
-void run_shrinkers(void)
+void run_shrinkers(gfp_t gfp_mask, bool allocation_failed)
 {
        struct shrinker *shrinker;
-       struct meminfo info;
+       struct sysinfo info;
        s64 want_shrink;
 
+       if (!(gfp_mask & GFP_KERNEL))
+               return;
+
        /* Fast out if there are no shrinkers to run. */
        if (list_empty(&shrinker_list))
                return;
 
-       info = read_meminfo();
-       want_shrink = (info.total >> 2) - info.available;
-
-       if (want_shrink <= 0)
+       if (allocation_failed) {
+               run_shrinkers_allocation_failed(gfp_mask);
                return;
+       }
+
+       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;
+       }
 
        mutex_lock(&shrinker_lock);
        list_for_each_entry(shrinker, &shrinker_list, list) {
                struct shrink_control sc = {
-                       .nr_to_scan = want_shrink >> PAGE_SHIFT
+                       .gfp_mask       = gfp_mask,
+                       .nr_to_scan     = want_shrink >> PAGE_SHIFT
                };
 
                shrinker->scan_objects(shrinker, &sc);
        }
        mutex_unlock(&shrinker_lock);
 }
+
+static int shrinker_thread(void *arg)
+{
+       while (!kthread_should_stop()) {
+               sleep(1);
+               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;
+}