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Date: Wed, 2 Nov 2022 20:06:21 +0800
From: "zhaoyang.huang" <zhaoyang.huang@...soc.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Vlastimil Babka <vbabka@...e.cz>,
Zhaoyang Huang <huangzhaoyang@...il.com>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>, <ke.wang@...soc.com>,
<steve.kang@...soc.com>
Subject: [RFC PATCH] mm: introduce accounting of page_owner via backtrace
From: Zhaoyang Huang <zhaoyang.huang@...soc.com>
Page_owner could be accounted and sort via its backtrace, which could
simplify the output.
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@...soc.com>
---
include/linux/page_owner.h | 7 +++
mm/page_owner.c | 113 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 120 insertions(+)
diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
index 119a0c9..c86a342 100644
--- a/include/linux/page_owner.h
+++ b/include/linux/page_owner.h
@@ -3,6 +3,13 @@
#define __LINUX_PAGE_OWNER_H
#include <linux/jump_label.h>
+#include <linux/stackdepot.h>
+
+struct hash_object {
+ int count;
+ depot_stack_handle_t trace_hash;
+ struct rb_node rb_node;
+};
#ifdef CONFIG_PAGE_OWNER
extern struct static_key_false page_owner_inited;
diff --git a/mm/page_owner.c b/mm/page_owner.c
index e4c6f3f..3d014fd 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -42,6 +42,12 @@ struct page_owner {
static depot_stack_handle_t early_handle;
static void init_early_allocated_pages(void);
+static void store_user_hash(depot_stack_handle_t trace_hash, int count);
+static DEFINE_SPINLOCK(stack_hash_lock);
+static struct hash_object ho_pool[8192];
+static int ho_pool_free_count = ARRAY_SIZE(ho_pool);
+struct rb_root user_hash_root = RB_ROOT;
+
static int __init early_page_owner_param(char *buf)
{
@@ -152,6 +158,8 @@ void __reset_page_owner(struct page *page, unsigned short order)
page_owner->free_handle = handle;
page_owner->free_ts_nsec = free_ts_nsec;
page_ext = page_ext_next(page_ext);
+ if (!i)
+ store_user_hash(page_owner->handle, -(1 << order));
}
}
@@ -190,6 +198,7 @@ noinline void __set_page_owner(struct page *page, unsigned short order,
return;
handle = save_stack(gfp_mask);
+ store_user_hash(handle, 1 << order);
__set_page_owner_handle(page_ext, handle, order, gfp_mask);
}
@@ -570,6 +579,105 @@ void __dump_page_owner(const struct page *page)
return 0;
}
+static void store_user_hash(depot_stack_handle_t trace_hash, int count)
+{
+ struct rb_node *rb_parent;
+ unsigned int trace_hash_parent;
+ struct rb_node **link = &user_hash_root.rb_node;
+ struct hash_object *hash_parent = NULL;
+ struct hash_object *hash_object = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&stack_hash_lock, flags);
+ while (*link) {
+ rb_parent = *link;
+ hash_parent = rb_entry(rb_parent, struct hash_object, rb_node);
+ trace_hash_parent = hash_parent->trace_hash;
+ if (trace_hash < trace_hash_parent)
+ link = &hash_parent->rb_node.rb_left;
+ else if (trace_hash_parent < trace_hash)
+ link = &hash_parent->rb_node.rb_right;
+ else {
+ hash_object = rb_entry(*link, struct hash_object, rb_node);
+ hash_object->count += count;
+ if (!RB_EMPTY_ROOT(&user_hash_root)
+ && !hash_object->count) {
+ rb_erase(&hash_object->rb_node, &user_hash_root);
+ }
+ spin_unlock_irqrestore(&stack_hash_lock, flags);
+ return;
+ }
+ }
+ /*
+ * hash_object is the 1st node represent this trace_hash
+ * insert it to user_hash_root
+ */
+ hash_object = ho_pool_free_count ? &ho_pool[--ho_pool_free_count] : NULL;
+ if (!hash_object) {
+ spin_unlock_irqrestore(&stack_hash_lock, flags);
+ return;
+ }
+ hash_object->trace_hash = trace_hash;
+ /* add the node to rb tree*/
+ rb_link_node(&hash_object->rb_node, rb_parent, link);
+ rb_insert_color(&hash_object->rb_node, &user_hash_root);
+ spin_unlock_irqrestore(&stack_hash_lock, flags);
+ return;
+}
+static ssize_t print_owner_stack(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+ struct hash_object *object;
+ struct rb_node *rb;
+ unsigned long *entries;
+ unsigned int nr_entries;
+ char *kbuf;
+ int i, ret = 0;
+ unsigned long flags;
+
+ count = min_t(size_t, count, PAGE_SIZE);
+ kbuf = kmalloc(count, GFP_KERNEL);
+ if (!kbuf)
+ return -ENOMEM;
+
+ rb = file->private_data ? (struct rb_node *)file->private_data : rb_first(&user_hash_root);
+ if(!rb)
+ return 0;
+ spin_lock_irqsave(&stack_hash_lock, flags);
+ object = rb_entry(rb, struct hash_object, rb_node);
+ if (object) {
+ while (!object->trace_hash || object->count <= 0) {
+ rb = rb_next(rb);
+ object = rb ? rb_entry(rb, struct hash_object, rb_node) : NULL;
+ if (!object) {
+ spin_unlock_irqrestore(&stack_hash_lock, flags);
+ kfree(kbuf);
+ return 0;
+ }
+ }
+ nr_entries = stack_depot_fetch(object->trace_hash, &entries);
+ ret += snprintf(kbuf + ret, count - ret, "count %d\n", object->count);
+ if (ret >= count)
+ goto err;
+ for (i = 0; i < nr_entries; i++) {
+ void *ptr = (void *)entries[i];
+ ret += snprintf(kbuf + ret, count - ret, " [<%p>] %pS\n", ptr, ptr);
+ if (ret >= count)
+ goto err;
+ }
+ }
+ file->private_data = (void *)rb_next(rb);
+ spin_unlock_irqrestore(&stack_hash_lock, flags);
+ if (copy_to_user(buf, kbuf, ret))
+ ret = -EFAULT;
+
+ kfree(kbuf);
+ return ret;
+err:
+ spin_unlock_irqrestore(&stack_hash_lock, flags);
+ kfree(kbuf);
+ return -ENOMEM;
+}
+
static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
{
unsigned long pfn = zone->zone_start_pfn;
@@ -661,6 +769,9 @@ static void init_early_allocated_pages(void)
static const struct file_operations proc_page_owner_operations = {
.read = read_page_owner,
};
+static const struct file_operations proc_page_owner_simple_operations = {
+ .read = print_owner_stack,
+};
static int __init pageowner_init(void)
{
@@ -671,6 +782,8 @@ static int __init pageowner_init(void)
debugfs_create_file("page_owner", 0400, NULL, NULL,
&proc_page_owner_operations);
+ debugfs_create_file("page_owner_simple", 0400, NULL, NULL,
+ &proc_page_owner_simple_operations);
return 0;
}
--
1.9.1
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