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Commit 7d39db14 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: Use struct flex_groups to calculate get_orlov_stats() 



Instead of looping over all of the block groups in a flex group
summing their summary statistics, start tracking used_dirs in struct
flex_groups, and use struct flex_groups instead.  This should save a
bit of CPU for mkdir-heavy workloads.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 9f24e420

fs/ext4/ext4.h

+1 −0
Original line number Diff line number Diff line
@@ -172,6 +172,7 @@ struct ext4_group_desc 
struct flex_groups {

	atomic_t free_inodes;

	atomic_t free_blocks;

	atomic_t used_dirs;

};



#define EXT4_BG_INODE_UNINIT	0x0001 /* Inode table/bitmap not in use */

fs/ext4/ialloc.c

+28 −17
Original line number Diff line number Diff line
@@ -267,6 +267,13 @@ void ext4_free_inode(handle_t *handle, struct inode *inode) 
			if (is_directory) {

				count = ext4_used_dirs_count(sb, gdp) - 1;

				ext4_used_dirs_set(sb, gdp, count);

				if (sbi->s_log_groups_per_flex) {

					ext4_group_t f;



					f = ext4_flex_group(sbi, block_group);

					atomic_dec(&sbi->s_flex_groups[f].free_inodes);

				}



			}

			gdp->bg_checksum = ext4_group_desc_csum(sbi,

							block_group, gdp);
@@ -424,25 +431,24 @@ void get_orlov_stats(struct super_block *sb, ext4_group_t g, 
		       int flex_size, struct orlov_stats *stats)

{

	struct ext4_group_desc *desc;

	ext4_group_t		ngroups = EXT4_SB(sb)->s_groups_count;

	int			i;

	struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;



	if (flex_size > 1) {

		stats->free_inodes = atomic_read(&flex_group[g].free_inodes);

		stats->free_blocks = atomic_read(&flex_group[g].free_blocks);

		stats->used_dirs = atomic_read(&flex_group[g].used_dirs);

		return;

	}



	desc = ext4_get_group_desc(sb, g, NULL);

	if (desc) {

		stats->free_inodes = ext4_free_inodes_count(sb, desc);

		stats->free_blocks = ext4_free_blks_count(sb, desc);

		stats->used_dirs = ext4_used_dirs_count(sb, desc);

	} else {

		stats->free_inodes = 0;

		stats->free_blocks = 0;

		stats->used_dirs = 0;



	g *= flex_size;



	for (i = 0; i < flex_size; i++) {

		if (g >= ngroups)

			break;

		desc = ext4_get_group_desc(sb, g++, NULL);

		if (!desc)

			continue;



		stats->free_inodes += ext4_free_inodes_count(sb, desc);

		stats->free_blocks += ext4_free_blks_count(sb, desc);

		stats->used_dirs += ext4_used_dirs_count(sb, desc);

	}

}
@@ -765,6 +771,11 @@ static int ext4_claim_inode(struct super_block *sb, 
	if (S_ISDIR(mode)) {

		count = ext4_used_dirs_count(sb, gdp) + 1;

		ext4_used_dirs_set(sb, gdp, count);

		if (sbi->s_log_groups_per_flex) {

			ext4_group_t f = ext4_flex_group(sbi, group);



			atomic_inc(&sbi->s_flex_groups[f].free_inodes);

		}

	}

	gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);

err_ret:

fs/ext4/super.c

+2 −0
Original line number Diff line number Diff line
@@ -1634,6 +1634,8 @@ static int ext4_fill_flex_info(struct super_block *sb) 
			   ext4_free_inodes_count(sb, gdp));

		atomic_set(&sbi->s_flex_groups[flex_group].free_blocks,

			   ext4_free_blks_count(sb, gdp));

		atomic_set(&sbi->s_flex_groups[flex_group].used_dirs,

			   ext4_used_dirs_count(sb, gdp));

	}



	return 1;