Commit f68f4063 authored by Harshad Shirwadkar's avatar Harshad Shirwadkar Committed by Theodore Ts'o
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ext4: add proc files to monitor new structures 



This patch adds a new file "mb_structs_summary" which allows us to see
the summary of the new allocator structures added in this
series. Here's the sample output of file:

optimize_scan: 1
max_free_order_lists:
        list_order_0_groups: 0
        list_order_1_groups: 0
        list_order_2_groups: 0
        list_order_3_groups: 0
        list_order_4_groups: 0
        list_order_5_groups: 0
        list_order_6_groups: 0
        list_order_7_groups: 0
        list_order_8_groups: 0
        list_order_9_groups: 0
        list_order_10_groups: 0
        list_order_11_groups: 0
        list_order_12_groups: 0
        list_order_13_groups: 40
fragment_size_tree:
        tree_min: 16384
        tree_max: 32768
        tree_nodes: 40

Signed-off-by: default avatarHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: default avatarAndreas Dilger <adilger@dilger.ca>
Reviewed-by: default avatarRitesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20210401172129.189766-7-harshadshirwadkar@gmail.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 196e402a

fs/ext4/ext4.h

+1 −0
Original line number Diff line number Diff line
@@ -2872,6 +2872,7 @@ 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_summary_ops;

extern long ext4_mb_stats;

extern long ext4_mb_max_to_scan;

extern int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset);

fs/ext4/mballoc.c

+86 −0
Original line number Diff line number Diff line
@@ -2963,6 +2963,92 @@ int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset) 
	return 0;

}



static void *ext4_mb_seq_structs_summary_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) + 1)

		return NULL;

	position = *pos + 1;

	return (void *) ((unsigned long) position);

}



static void *ext4_mb_seq_structs_summary_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) + 1)

		return NULL;

	position = *pos + 1;

	return (void *) ((unsigned long) position);

}



static int ext4_mb_seq_structs_summary_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 *grp;

	struct rb_node *n;

	unsigned int count, min, max;



	position--;

	if (position >= MB_NUM_ORDERS(sb)) {

		seq_puts(seq, "fragment_size_tree:\n");

		n = rb_first(&sbi->s_mb_avg_fragment_size_root);

		if (!n) {

			seq_puts(seq, "\ttree_min: 0\n\ttree_max: 0\n\ttree_nodes: 0\n");

			return 0;

		}

		grp = rb_entry(n, struct ext4_group_info, bb_avg_fragment_size_rb);

		min = grp->bb_fragments ? grp->bb_free / grp->bb_fragments : 0;

		count = 1;

		while (rb_next(n)) {

			count++;

			n = rb_next(n);

		}

		grp = rb_entry(n, struct ext4_group_info, bb_avg_fragment_size_rb);

		max = grp->bb_fragments ? grp->bb_free / grp->bb_fragments : 0;



		seq_printf(seq, "\ttree_min: %u\n\ttree_max: %u\n\ttree_nodes: %u\n",

			   min, max, count);

		return 0;

	}



	if (position == 0) {

		seq_printf(seq, "optimize_scan: %d\n",

			   test_opt2(sb, MB_OPTIMIZE_SCAN) ? 1 : 0);

		seq_puts(seq, "max_free_order_lists:\n");

	}

	count = 0;

	list_for_each_entry(grp, &sbi->s_mb_largest_free_orders[position],

			    bb_largest_free_order_node)

		count++;

	seq_printf(seq, "\tlist_order_%u_groups: %u\n",

		   (unsigned int)position, count);



	return 0;

}



static void ext4_mb_seq_structs_summary_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_summary_ops = {

	.start  = ext4_mb_seq_structs_summary_start,

	.next   = ext4_mb_seq_structs_summary_next,

	.stop   = ext4_mb_seq_structs_summary_stop,

	.show   = ext4_mb_seq_structs_summary_show,

};



static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)

{

	int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;

fs/ext4/sysfs.c

+2 −0
Original line number Diff line number Diff line
@@ -534,6 +534,8 @@ int ext4_register_sysfs(struct super_block *sb) 
				&ext4_mb_seq_groups_ops, sb);

		proc_create_single_data("mb_stats", 0444, sbi->s_proc,

				ext4_seq_mb_stats_show, sb);

		proc_create_seq_data("mb_structs_summary", 0444, sbi->s_proc,

				&ext4_mb_seq_structs_summary_ops, sb);

	}

	return 0;

}