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Date: Fri, 29 Jan 2021 14:29:31 -0800
From: Harshad Shirwadkar <harshadshirwadkar@...il.com>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, Harshad Shirwadkar <harshadshirwadkar@...il.com>
Subject: [PATCH 4/4] ext4: add proc files to monitor new structures
This patch adds a new file "mb_structs" which allows us to see the
largest free order lists and the serialized average fragment tree.
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@...il.com>
---
fs/ext4/ext4.h | 1 +
fs/ext4/mballoc.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/sysfs.c | 2 ++
3 files changed, 82 insertions(+)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index da12a083bf52..835e304e3113 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2809,6 +2809,7 @@ int __init ext4_fc_init_dentry_cache(void);
/* mballoc.c */
extern const struct seq_operations ext4_mb_seq_groups_ops;
+extern const struct seq_operations ext4_mb_seq_structs_ops;
extern long ext4_mb_stats;
extern long ext4_mb_max_to_scan;
extern int ext4_mb_init(struct super_block *);
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 413259477b03..ec4656903bd4 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2741,6 +2741,85 @@ const struct seq_operations ext4_mb_seq_groups_ops = {
.show = ext4_mb_seq_groups_show,
};
+static void *ext4_mb_seq_structs_start(struct seq_file *seq, loff_t *pos)
+{
+ struct super_block *sb = PDE_DATA(file_inode(seq->file));
+ unsigned long position;
+
+ read_lock(&EXT4_SB(sb)->s_mb_rb_lock);
+
+ if (*pos < 0 || *pos >= MB_NUM_ORDERS(sb) + ext4_get_groups_count(sb))
+ return NULL;
+ position = *pos + 1;
+ return (void *) ((unsigned long) position);
+}
+
+static void *ext4_mb_seq_structs_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct super_block *sb = PDE_DATA(file_inode(seq->file));
+ unsigned long position;
+
+ ++*pos;
+ if (*pos < 0 || *pos >= MB_NUM_ORDERS(sb) + ext4_get_groups_count(sb))
+ return NULL;
+ position = *pos + 1;
+ return (void *) ((unsigned long) position);
+}
+
+static int ext4_mb_seq_structs_show(struct seq_file *seq, void *v)
+{
+ struct super_block *sb = PDE_DATA(file_inode(seq->file));
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ unsigned long position = ((unsigned long) v);
+ struct ext4_group_info *grpinfo;
+ struct rb_node *n;
+ int i;
+
+ position--;
+
+ if (position >= MB_NUM_ORDERS(sb)) {
+ position -= MB_NUM_ORDERS(sb);
+ if (position == 0)
+ seq_puts(seq, "Group, Avg Fragment Size\n");
+ n = rb_first(&sbi->s_mb_avg_fragment_size_root);
+ for (i = 0; n && i < position; i++)
+ n = rb_next(n);
+ if (!n)
+ return 0;
+ grpinfo = rb_entry(n, struct ext4_group_info, bb_avg_fragment_size_rb);
+ seq_printf(seq, "%d, %d\n",
+ grpinfo->bb_group,
+ grpinfo->bb_fragments ? grpinfo->bb_free / grpinfo->bb_fragments : 0);
+ return 0;
+ }
+
+ if (position == 0)
+ seq_puts(seq, "Largest Free Order Lists:\n");
+
+ seq_printf(seq, "[%ld]: ", position);
+ list_for_each_entry(grpinfo, &sbi->s_mb_largest_free_orders[position],
+ bb_largest_free_order_node) {
+ seq_printf(seq, "%d ", grpinfo->bb_group);
+ }
+ seq_puts(seq, "\n");
+
+ return 0;
+}
+
+static void ext4_mb_seq_structs_stop(struct seq_file *seq, void *v)
+{
+ struct super_block *sb = PDE_DATA(file_inode(seq->file));
+
+ read_unlock(&EXT4_SB(sb)->s_mb_rb_lock);
+}
+
+const struct seq_operations ext4_mb_seq_structs_ops = {
+ .start = ext4_mb_seq_structs_start,
+ .next = ext4_mb_seq_structs_next,
+ .stop = ext4_mb_seq_structs_stop,
+ .show = ext4_mb_seq_structs_show,
+};
+
static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
{
int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 4e27fe6ed3ae..828d58b98310 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -527,6 +527,8 @@ int ext4_register_sysfs(struct super_block *sb)
ext4_fc_info_show, sb);
proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
&ext4_mb_seq_groups_ops, sb);
+ proc_create_seq_data("mb_structs", 0444, sbi->s_proc,
+ &ext4_mb_seq_structs_ops, sb);
}
return 0;
}
--
2.30.0.365.g02bc693789-goog
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