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ext4: Use atomic_t's in struct flex_groups

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Reduce pressure on the sb_bgl_lock family of locks by using atomic_t's
to track the number of free blocks and inodes in each flex_group.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
2009-03-04 19:09:10 -05:00
parent b713a5ec55
commit 9f24e4208f
6 changed files with 30 additions and 37 deletions
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33
fs/ext4/ialloc.c
View File

@@ -189,7 +189,6 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
struct ext4_super_block *es;
struct ext4_sb_info *sbi;
int fatal = 0, err, count, cleared;
ext4_group_t flex_group;
if (atomic_read(&inode->i_count) > 1) {
printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
@@ -277,10 +276,10 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
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));
ext4_group_t f;
f = ext4_flex_group(sbi, block_group);
atomic_inc(&sbi->s_flex_groups[f].free_inodes);
}
}
BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
@@ -360,9 +359,9 @@ static int find_group_flex(struct super_block *sb, struct inode *parent,
sbi->s_log_groups_per_flex;
find_close_to_parent:
flexbg_free_blocks = flex_group[best_flex].free_blocks;
flexbg_free_blocks = atomic_read(&flex_group[best_flex].free_blocks);
flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
if (flex_group[best_flex].free_inodes &&
if (atomic_read(&flex_group[best_flex].free_inodes) &&
flex_freeb_ratio > free_block_ratio)
goto found_flexbg;
@@ -375,24 +374,24 @@ find_close_to_parent:
if (i == parent_fbg_group || i == parent_fbg_group - 1)
continue;
flexbg_free_blocks = flex_group[i].free_blocks;
flexbg_free_blocks = atomic_read(&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) {
(atomic_read(&flex_group[i].free_inodes))) {
best_flex = i;
goto found_flexbg;
}
if (flex_group[best_flex].free_inodes == 0 ||
(flex_group[i].free_blocks >
flex_group[best_flex].free_blocks &&
flex_group[i].free_inodes))
if ((atomic_read(&flex_group[best_flex].free_inodes) == 0) ||
((atomic_read(&flex_group[i].free_blocks) >
atomic_read(&flex_group[best_flex].free_blocks)) &&
atomic_read(&flex_group[i].free_inodes)))
best_flex = i;
}
if (!flex_group[best_flex].free_inodes ||
!flex_group[best_flex].free_blocks)
if (!atomic_read(&flex_group[best_flex].free_inodes) ||
!atomic_read(&flex_group[best_flex].free_blocks))
return -1;
found_flexbg:
@@ -960,9 +959,7 @@ got:
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));
atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
}
inode->i_uid = current_fsuid();