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Message-Id: <20220422202644.799732-4-roman.gushchin@linux.dev>
Date: Fri, 22 Apr 2022 13:26:40 -0700
From: Roman Gushchin <roman.gushchin@...ux.dev>
To: Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org
Cc: Dave Chinner <dchinner@...hat.com>, linux-kernel@...r.kernel.org,
Yang Shi <shy828301@...il.com>,
Kent Overstreet <kent.overstreet@...il.com>,
Hillf Danton <hdanton@...a.com>,
Roman Gushchin <roman.gushchin@...ux.dev>
Subject: [PATCH v2 3/7] mm: introduce memcg interfaces for shrinker debugfs
This commit introduces "count_memcg" and "scan_memcg" interfaces
for memcg-aware shrinkers.
Count_memcg using the following format:
<cgroup inode number1> <count2>
<cgroup inode number2> <count2>
...
Memory cgroups with 0 associated objects are skipped.
Signed-off-by: Roman Gushchin <roman.gushchin@...ux.dev>
---
mm/shrinker_debug.c | 186 +++++++++++++++++++++++++++++++++-----------
1 file changed, 139 insertions(+), 47 deletions(-)
diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c
index 4df7382a0737..002d44d6ad56 100644
--- a/mm/shrinker_debug.c
+++ b/mm/shrinker_debug.c
@@ -1,8 +1,10 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/idr.h>
+#include <linux/slab.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/shrinker.h>
+#include <linux/memcontrol.h>
/* defined in vmscan.c */
extern struct rw_semaphore shrinker_rwsem;
@@ -11,25 +13,25 @@ extern struct list_head shrinker_list;
static DEFINE_IDA(shrinker_debugfs_ida);
static struct dentry *shrinker_debugfs_root;
-static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
+static unsigned long shrinker_count_objects(struct shrinker *shrinker,
+ struct mem_cgroup *memcg,
+ unsigned long *count_per_node)
{
- struct shrinker *shrinker = (struct shrinker *)m->private;
unsigned long nr, total = 0;
- int ret, nid;
-
- ret = down_read_killable(&shrinker_rwsem);
- if (ret)
- return ret;
+ int nid;
for_each_node(nid) {
struct shrink_control sc = {
.gfp_mask = GFP_KERNEL,
.nid = nid,
+ .memcg = memcg,
};
nr = shrinker->count_objects(shrinker, &sc);
if (nr == SHRINK_EMPTY)
nr = 0;
+ if (count_per_node)
+ count_per_node[nid] = nr;
total += nr;
if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
@@ -37,32 +39,17 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
cond_resched();
}
- up_read(&shrinker_rwsem);
-
- seq_printf(m, "%lu\n", total);
- return ret;
+ return total;
}
-DEFINE_SHOW_ATTRIBUTE(shrinker_debugfs_count);
-static ssize_t shrinker_debugfs_scan_write(struct file *file,
- const char __user *buf,
- size_t size, loff_t *pos)
+static int shrinker_scan_objects(struct shrinker *shrinker,
+ struct mem_cgroup *memcg,
+ unsigned long nr_to_scan)
{
- struct shrinker *shrinker = (struct shrinker *)file->private_data;
- unsigned long nr, total = 0, nr_to_scan;
- unsigned long *count_per_node = NULL;
- int nid;
- char kbuf[24];
- int read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1);
- ssize_t ret;
-
- if (copy_from_user(kbuf, buf, read_len))
- return -EFAULT;
- kbuf[read_len] = '\0';
-
- if (kstrtoul(kbuf, 10, &nr_to_scan))
- return -EINVAL;
+ unsigned long *count_per_node;
+ unsigned long total, nr;
+ int ret, nid;
ret = down_read_killable(&shrinker_rwsem);
if (ret)
@@ -80,20 +67,7 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
goto out;
}
- for_each_node(nid) {
- struct shrink_control sc = {
- .gfp_mask = GFP_KERNEL,
- .nid = nid,
- };
-
- nr = shrinker->count_objects(shrinker, &sc);
- if (nr == SHRINK_EMPTY)
- nr = 0;
- count_per_node[nid] = nr;
- total += nr;
-
- cond_resched();
- }
+ total = shrinker_count_objects(shrinker, memcg, count_per_node);
}
for_each_node(nid) {
@@ -102,13 +76,13 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
.nid = nid,
};
- if (shrinker->flags & SHRINKER_NUMA_AWARE) {
+ if (count_per_node) {
sc.nr_to_scan = nr_to_scan * count_per_node[nid] /
(total ? total : 1);
sc.nr_scanned = sc.nr_to_scan;
} else {
sc.nr_to_scan = nr_to_scan;
- sc.nr_scanned = sc.nr_to_scan;
+ sc.nr_scanned = nr_to_scan;
}
nr = shrinker->scan_objects(shrinker, &sc);
@@ -119,15 +93,51 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
break;
cond_resched();
-
}
- ret = size;
out:
up_read(&shrinker_rwsem);
kfree(count_per_node);
return ret;
}
+static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
+{
+ struct shrinker *shrinker = (struct shrinker *)m->private;
+ int ret;
+
+ ret = down_read_killable(&shrinker_rwsem);
+ if (!ret) {
+ unsigned long total = shrinker_count_objects(shrinker, NULL, NULL);
+
+ up_read(&shrinker_rwsem);
+ seq_printf(m, "%lu\n", total);
+ }
+ return ret;
+}
+DEFINE_SHOW_ATTRIBUTE(shrinker_debugfs_count);
+
+static ssize_t shrinker_debugfs_scan_write(struct file *file,
+ const char __user *buf,
+ size_t size, loff_t *pos)
+{
+ struct shrinker *shrinker = (struct shrinker *)file->private_data;
+ unsigned long nr_to_scan;
+ char kbuf[24];
+ int read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1);
+ ssize_t ret;
+
+ if (copy_from_user(kbuf, buf, read_len))
+ return -EFAULT;
+ kbuf[read_len] = '\0';
+
+ if (kstrtoul(kbuf, 10, &nr_to_scan))
+ return -EINVAL;
+
+ ret = shrinker_scan_objects(shrinker, NULL, nr_to_scan);
+
+ return ret ? ret : size;
+}
+
static int shrinker_debugfs_scan_open(struct inode *inode, struct file *file)
{
file->private_data = inode->i_private;
@@ -140,6 +150,78 @@ static const struct file_operations shrinker_debugfs_scan_fops = {
.write = shrinker_debugfs_scan_write,
};
+#ifdef CONFIG_MEMCG
+static int shrinker_debugfs_count_memcg_show(struct seq_file *m, void *v)
+{
+ struct shrinker *shrinker = (struct shrinker *)m->private;
+ struct mem_cgroup *memcg;
+ unsigned long total;
+ int ret;
+
+ ret = down_read_killable(&shrinker_rwsem);
+ if (ret)
+ return ret;
+ rcu_read_lock();
+
+ memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ do {
+ if (!mem_cgroup_online(memcg))
+ continue;
+
+ total = shrinker_count_objects(shrinker, memcg, NULL);
+ if (!total)
+ continue;
+
+ seq_printf(m, "%lu %lu\n", mem_cgroup_ino(memcg), total);
+ } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
+
+ rcu_read_unlock();
+ up_read(&shrinker_rwsem);
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(shrinker_debugfs_count_memcg);
+
+static ssize_t shrinker_debugfs_scan_memcg_write(struct file *file,
+ const char __user *buf,
+ size_t size, loff_t *pos)
+{
+ struct shrinker *shrinker = (struct shrinker *)file->private_data;
+ unsigned long nr_to_scan, ino;
+ struct mem_cgroup *memcg;
+ char kbuf[48];
+ int read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1);
+ ssize_t ret;
+
+ if (copy_from_user(kbuf, buf, read_len))
+ return -EFAULT;
+ kbuf[read_len] = '\0';
+
+ if (sscanf(kbuf, "%lu %lu", &ino, &nr_to_scan) < 2)
+ return -EINVAL;
+
+ memcg = mem_cgroup_get_from_ino(ino);
+ if (!memcg || IS_ERR(memcg))
+ return -ENOENT;
+
+ if (!mem_cgroup_online(memcg)) {
+ mem_cgroup_put(memcg);
+ return -ENOENT;
+ }
+
+ ret = shrinker_scan_objects(shrinker, memcg, nr_to_scan);
+ mem_cgroup_put(memcg);
+
+ return ret ? ret : size;
+}
+
+static const struct file_operations shrinker_debugfs_scan_memcg_fops = {
+ .owner = THIS_MODULE,
+ .open = shrinker_debugfs_scan_open,
+ .write = shrinker_debugfs_scan_memcg_write,
+};
+#endif
+
int shrinker_debugfs_add(struct shrinker *shrinker)
{
struct dentry *entry;
@@ -173,6 +255,16 @@ int shrinker_debugfs_add(struct shrinker *shrinker)
debugfs_create_file("scan", 0440, entry, shrinker,
&shrinker_debugfs_scan_fops);
+#ifdef CONFIG_MEMCG
+ /* create memcg interfaces */
+ if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
+ debugfs_create_file("count_memcg", 0220, entry, shrinker,
+ &shrinker_debugfs_count_memcg_fops);
+ debugfs_create_file("scan_memcg", 0440, entry, shrinker,
+ &shrinker_debugfs_scan_memcg_fops);
+ }
+#endif
+
return 0;
}
--
2.35.1
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