summaryrefslogtreecommitdiffstats
path: root/fs/ext4/ialloc.c
diff options
context:
space:
mode:
authorJose R. Santos <jrs@us.ibm.com>2008-07-11 19:27:31 -0400
committerTheodore Ts'o <tytso@mit.edu>2008-07-11 19:27:31 -0400
commit772cb7c83ba256a11c7bf99a11bef3858d23767c (patch)
treea42b97e5cbd870a76b2646c2dcb658a92c53f637 /fs/ext4/ialloc.c
parent736603ab297506f4396cb5af592004499950fcfd (diff)
downloadlinux-772cb7c83ba256a11c7bf99a11bef3858d23767c.tar.bz2
ext4: New inode allocation for FLEX_BG meta-data groups.
This patch mostly controls the way inode are allocated in order to make ialloc aware of flex_bg block group grouping. It achieves this by bypassing the Orlov allocator when block group meta-data are packed toghether through mke2fs. Since the impact on the block allocator is minimal, this patch should have little or no effect on other block allocation algorithms. By controlling the inode allocation, it can basically control where the initial search for new block begins and thus indirectly manipulate the block allocator. This allocator favors data and meta-data locality so the disk will gradually be filled from block group zero upward. This helps improve performance by reducing seek time. Since the group of inode tables within one flex_bg are treated as one giant inode table, uninitialized block groups would not need to partially initialize as many inode table as with Orlov which would help fsck time as the filesystem usage goes up. Signed-off-by: Jose R. Santos <jrs@us.ibm.com> Signed-off-by: Valerie Clement <valerie.clement@bull.net> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/ialloc.c')
-rw-r--r--fs/ext4/ialloc.c96
1 files changed, 96 insertions, 0 deletions
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index b30cc79b9fcb..8b0a10acd708 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -157,6 +157,7 @@ void ext4_free_inode (handle_t *handle, struct inode * inode)
struct ext4_super_block * es;
struct ext4_sb_info *sbi;
int fatal = 0, err;
+ ext4_group_t flex_group;
if (atomic_read(&inode->i_count) > 1) {
printk ("ext4_free_inode: inode has count=%d\n",
@@ -232,6 +233,12 @@ void ext4_free_inode (handle_t *handle, struct inode * inode)
if (is_directory)
percpu_counter_dec(&sbi->s_dirs_counter);
+ if (sbi->s_log_groups_per_flex) {
+ flex_group = ext4_flex_group(sbi, block_group);
+ spin_lock(sb_bgl_lock(sbi, flex_group));
+ sbi->s_flex_groups[flex_group].free_inodes++;
+ spin_unlock(sb_bgl_lock(sbi, flex_group));
+ }
}
BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
err = ext4_journal_dirty_metadata(handle, bh2);
@@ -286,6 +293,80 @@ static int find_group_dir(struct super_block *sb, struct inode *parent,
return ret;
}
+#define free_block_ratio 10
+
+static int find_group_flex(struct super_block *sb, struct inode *parent,
+ ext4_group_t *best_group)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_group_desc *desc;
+ struct buffer_head *bh;
+ struct flex_groups *flex_group = sbi->s_flex_groups;
+ ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
+ ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
+ ext4_group_t ngroups = sbi->s_groups_count;
+ int flex_size = ext4_flex_bg_size(sbi);
+ ext4_group_t best_flex = parent_fbg_group;
+ int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
+ int flexbg_free_blocks;
+ int flex_freeb_ratio;
+ ext4_group_t n_fbg_groups;
+ ext4_group_t i;
+
+ n_fbg_groups = (sbi->s_groups_count + flex_size - 1) >>
+ sbi->s_log_groups_per_flex;
+
+find_close_to_parent:
+ flexbg_free_blocks = flex_group[best_flex].free_blocks;
+ flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
+ if (flex_group[best_flex].free_inodes &&
+ flex_freeb_ratio > free_block_ratio)
+ goto found_flexbg;
+
+ if (best_flex && best_flex == parent_fbg_group) {
+ best_flex--;
+ goto find_close_to_parent;
+ }
+
+ for (i = 0; i < n_fbg_groups; i++) {
+ if (i == parent_fbg_group || i == parent_fbg_group - 1)
+ continue;
+
+ flexbg_free_blocks = flex_group[i].free_blocks;
+ flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
+
+ if (flex_freeb_ratio > free_block_ratio &&
+ flex_group[i].free_inodes) {
+ best_flex = i;
+ goto found_flexbg;
+ }
+
+ if (best_flex < 0 ||
+ (flex_group[i].free_blocks >
+ flex_group[best_flex].free_blocks &&
+ flex_group[i].free_inodes))
+ best_flex = i;
+ }
+
+ if (!flex_group[best_flex].free_inodes ||
+ !flex_group[best_flex].free_blocks)
+ return -1;
+
+found_flexbg:
+ for (i = best_flex * flex_size; i < ngroups &&
+ i < (best_flex + 1) * flex_size; i++) {
+ desc = ext4_get_group_desc(sb, i, &bh);
+ if (le16_to_cpu(desc->bg_free_inodes_count)) {
+ *best_group = i;
+ goto out;
+ }
+ }
+
+ return -1;
+out:
+ return 0;
+}
+
/*
* Orlov's allocator for directories.
*
@@ -501,6 +582,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
struct inode *ret;
ext4_group_t i;
int free = 0;
+ ext4_group_t flex_group;
/* Cannot create files in a deleted directory */
if (!dir || !dir->i_nlink)
@@ -514,6 +596,12 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
sbi = EXT4_SB(sb);
es = sbi->s_es;
+
+ if (sbi->s_log_groups_per_flex) {
+ ret2 = find_group_flex(sb, dir, &group);
+ goto got_group;
+ }
+
if (S_ISDIR(mode)) {
if (test_opt (sb, OLDALLOC))
ret2 = find_group_dir(sb, dir, &group);
@@ -522,6 +610,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
} else
ret2 = find_group_other(sb, dir, &group);
+got_group:
err = -ENOSPC;
if (ret2 == -1)
goto out;
@@ -676,6 +765,13 @@ got:
percpu_counter_inc(&sbi->s_dirs_counter);
sb->s_dirt = 1;
+ if (sbi->s_log_groups_per_flex) {
+ flex_group = ext4_flex_group(sbi, group);
+ spin_lock(sb_bgl_lock(sbi, flex_group));
+ sbi->s_flex_groups[flex_group].free_inodes--;
+ spin_unlock(sb_bgl_lock(sbi, flex_group));
+ }
+
inode->i_uid = current->fsuid;
if (test_opt (sb, GRPID))
inode->i_gid = dir->i_gid;