Provide APIs to drivers so that they can show its memory usage on
/proc/meminfo_extra.
int register_meminfo_extra(atomic_long_t *val, int shift,
const char *name);
int unregister_meminfo_extra(atomic_long_t *val);
Signed-off-by: Jaewon Kim <jaewon31.kim@xxxxxxxxxxx>
---
v2: move to /proc/meminfo_extra as a new file, meminfo_extra.c
use rcu to reduce lock overhead
v1: print info at /proc/meminfo
---
fs/proc/Makefile | 1 +
fs/proc/meminfo_extra.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/mm.h | 4 ++
mm/page_alloc.c | 1 +
4 files changed, 129 insertions(+)
create mode 100644 fs/proc/meminfo_extra.c
diff --git a/fs/proc/Makefile b/fs/proc/Makefile
index bd08616ed8ba..83d2f55591c6 100644
--- a/fs/proc/Makefile
+++ b/fs/proc/Makefile
@@ -19,6 +19,7 @@ proc-y += devices.o
proc-y += interrupts.o
proc-y += loadavg.o
proc-y += meminfo.o
+proc-y += meminfo_extra.o
proc-y += stat.o
proc-y += uptime.o
proc-y += util.o
diff --git a/fs/proc/meminfo_extra.c b/fs/proc/meminfo_extra.c
new file mode 100644
index 000000000000..bd3f0d2b7fb7
--- /dev/null
+++ b/fs/proc/meminfo_extra.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+
+static void show_val_kb(struct seq_file *m, const char *s, unsigned long num)
+{
+ seq_put_decimal_ull_width(m, s, num << (PAGE_SHIFT - 10), 8);
+ seq_write(m, " kB\n", 4);
+}
+
+static LIST_HEAD(meminfo_head);
+static DEFINE_SPINLOCK(meminfo_lock);
+
+#define NAME_SIZE 15
+#define NAME_BUF_SIZE (NAME_SIZE + 2) /* ':' and '\0' */
+
+struct meminfo_extra {
+ struct list_head list;
+ atomic_long_t *val;
+ int shift_for_page;
+ char name[NAME_BUF_SIZE];
+ char name_pad[NAME_BUF_SIZE];
+};
+
+int register_meminfo_extra(atomic_long_t *val, int shift, const char *name)
+{
+ struct meminfo_extra *meminfo, *memtemp;
+ int len;
+ int error = 0;
+
+ meminfo = kzalloc(sizeof(*meminfo), GFP_KERNEL);
+ if (!meminfo) {
+ error = -ENOMEM;
+ goto out;
+ }
+
+ meminfo->val = val;
+ meminfo->shift_for_page = shift;
+ strncpy(meminfo->name, name, NAME_SIZE);
+ len = strlen(meminfo->name);
+ meminfo->name[len] = ':';
+ strncpy(meminfo->name_pad, meminfo->name, NAME_BUF_SIZE);
+ while (++len < NAME_BUF_SIZE - 1)
+ meminfo->name_pad[len] = ' ';
+
+ spin_lock(&meminfo_lock);
+ list_for_each_entry_rcu(memtemp, &meminfo_head, list) {
+ if (memtemp->val == val) {
+ error = -EINVAL;
+ break;
+ }
+ }
+ if (!error)
+ list_add_tail_rcu(&meminfo->list, &meminfo_head);
+ spin_unlock(&meminfo_lock);
+ if (error)
+ kfree(meminfo);
+out:
+
+ return error;
+}
+EXPORT_SYMBOL(register_meminfo_extra);
+
+int unregister_meminfo_extra(atomic_long_t *val)
+{
+ struct meminfo_extra *memtemp;
+ int error = -EINVAL;
+
+ spin_lock(&meminfo_lock);
+ list_for_each_entry_rcu(memtemp, &meminfo_head, list) {
+ if (memtemp->val == val) {
+ list_del_rcu(&memtemp->list);
+ error = 0;
+ break;
+ }
+ }
+ spin_unlock(&meminfo_lock);
+ if (!error) {
+ synchronize_rcu();
+ kfree(memtemp);
+ }
+
+ return error;
+}
+EXPORT_SYMBOL(unregister_meminfo_extra);
+
+static void __meminfo_extra(struct seq_file *m)
+{
+ struct meminfo_extra *memtemp;
+ unsigned long nr_page;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(memtemp, &meminfo_head, list) {
+ nr_page = (unsigned long)atomic_long_read(memtemp->val);
+ nr_page = nr_page >> memtemp->shift_for_page;
+ if (m)
+ show_val_kb(m, memtemp->name_pad, nr_page);
+ else
+ pr_cont("%s%lukB ", memtemp->name, nr_page);
+ }
+ rcu_read_unlock();
+}
+
+void show_meminfo_extra(void)
+{
+ __meminfo_extra(NULL);
+}
+
+static int meminfo_extra_proc_show(struct seq_file *m, void *v)
+{
+ __meminfo_extra(m);
+
+ return 0;
+}
+
+static int __init proc_meminfo_extra_init(void)
+{
+ proc_create_single("meminfo_extra", 0, NULL, meminfo_extra_proc_show);
+ return 0;
+}
+fs_initcall(proc_meminfo_extra_init);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 52269e56c514..55317161ab57 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2898,6 +2898,10 @@ void __init setup_nr_node_ids(void);
static inline void setup_nr_node_ids(void) {}
#endif
+void show_meminfo_extra(void);
+int register_meminfo_extra(atomic_long_t *val, int shift, const char *name);
+int unregister_meminfo_extra(atomic_long_t *val);
+
extern int memcmp_pages(struct page *page1, struct page *page2);
static inline int pages_identical(struct page *page1, struct page *page2)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3c4eb750a199..db1be9a39783 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5229,6 +5229,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
struct zone *zone;
pg_data_t *pgdat;
+ show_meminfo_extra();
for_each_populated_zone(zone) {
if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
continue;
--
2.13.7
