--- zzzz-none-000/linux-3.10.107/fs/drop_caches.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/drop_caches.c	2021-02-04 17:41:59.000000000 +0000
@@ -17,7 +17,7 @@
 {
 	struct inode *inode, *toput_inode = NULL;
 
-	spin_lock(&inode_sb_list_lock);
+	spin_lock(&sb->s_inode_list_lock);
 	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
 		spin_lock(&inode->i_lock);
 		if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
@@ -27,29 +27,19 @@
 		}
 		__iget(inode);
 		spin_unlock(&inode->i_lock);
-		spin_unlock(&inode_sb_list_lock);
+		spin_unlock(&sb->s_inode_list_lock);
+
 		invalidate_mapping_pages(inode->i_mapping, 0, -1);
 		iput(toput_inode);
 		toput_inode = inode;
-		spin_lock(&inode_sb_list_lock);
+
+		spin_lock(&sb->s_inode_list_lock);
 	}
-	spin_unlock(&inode_sb_list_lock);
+	spin_unlock(&sb->s_inode_list_lock);
 	iput(toput_inode);
 }
 
-static void drop_slab(void)
-{
-	int nr_objects;
-	struct shrink_control shrink = {
-		.gfp_mask = GFP_KERNEL,
-	};
-
-	do {
-		nr_objects = shrink_slab(&shrink, 1000, 1000);
-	} while (nr_objects > 10);
-}
-
-int drop_caches_sysctl_handler(ctl_table *table, int write,
+int drop_caches_sysctl_handler(struct ctl_table *table, int write,
 	void __user *buffer, size_t *length, loff_t *ppos)
 {
 	int ret;
@@ -58,10 +48,22 @@
 	if (ret)
 		return ret;
 	if (write) {
-		if (sysctl_drop_caches & 1)
+		static int stfu;
+
+		if (sysctl_drop_caches & 1) {
 			iterate_supers(drop_pagecache_sb, NULL);
-		if (sysctl_drop_caches & 2)
+			count_vm_event(DROP_PAGECACHE);
+		}
+		if (sysctl_drop_caches & 2) {
 			drop_slab();
+			count_vm_event(DROP_SLAB);
+		}
+		if (!stfu) {
+			pr_info("%s (%d): drop_caches: %d\n",
+				current->comm, task_pid_nr(current),
+				sysctl_drop_caches);
+		}
+		stfu |= sysctl_drop_caches & 4;
 	}
 	return 0;
 }