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@xxxxxxx>
---
fs/ext4/balloc.c | 5 ++---
fs/ext4/ext4.h | 4 ++--
fs/ext4/ialloc.c | 33 +++++++++++++++------------------
fs/ext4/mballoc.c | 9 +++------
fs/ext4/resize.c | 8 ++++----
fs/ext4/super.c | 8 ++++----
6 files changed, 30 insertions(+), 37 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index e1234f3..070ec0f 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -470,9 +470,8 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
- spin_lock(sb_bgl_lock(sbi, flex_group));
- sbi->s_flex_groups[flex_group].free_blocks += blocks_freed;
- spin_unlock(sb_bgl_lock(sbi, flex_group));
+ atomic_add(blocks_freed,
+ &sbi->s_flex_groups[flex_group].free_blocks);
}
/*
* request to reload the buddy with the
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2c165fa..50c92a8 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -169,8 +169,8 @@ struct ext4_group_desc
*/
struct flex_groups {
- __u32 free_inodes;
- __u32 free_blocks;
+ atomic_t free_inodes;
+ atomic_t free_blocks;
};
#define EXT4_BG_INODE_UNINIT 0x0001 /* Inode table/bitmap not in use */
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 847a357..692fd0d 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -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:
@@ -958,9 +957,7 @@ 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();
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 7e729cb..33ed0c0 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3041,9 +3041,8 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi,
ac->ac_b_ex.fe_group);
- spin_lock(sb_bgl_lock(sbi, flex_group));
- sbi->s_flex_groups[flex_group].free_blocks -= ac->ac_b_ex.fe_len;
- spin_unlock(sb_bgl_lock(sbi, flex_group));
+ atomic_sub(ac->ac_b_ex.fe_len,
+ &sbi->s_flex_groups[flex_group].free_blocks);
}
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
@@ -4871,9 +4870,7 @@ do_more:
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
- spin_lock(sb_bgl_lock(sbi, flex_group));
- sbi->s_flex_groups[flex_group].free_blocks += count;
- spin_unlock(sb_bgl_lock(sbi, flex_group));
+ atomic_add(count, &sbi->s_flex_groups[flex_group].free_blocks);
}
ext4_mb_release_desc(&e4b);
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index c06886a..546c7dd 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -938,10 +938,10 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
ext4_group_t flex_group;
flex_group = ext4_flex_group(sbi, input->group);
- sbi->s_flex_groups[flex_group].free_blocks +=
- input->free_blocks_count;
- sbi->s_flex_groups[flex_group].free_inodes +=
- EXT4_INODES_PER_GROUP(sb);
+ atomic_add(input->free_blocks_count,
+ &sbi->s_flex_groups[flex_group].free_blocks);
+ atomic_add(EXT4_INODES_PER_GROUP(sb),
+ &sbi->s_flex_groups[flex_group].free_inodes);
}
ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 904bbab..f34ddf8 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1619,10 +1619,10 @@ static int ext4_fill_flex_info(struct super_block *sb)
gdp = ext4_get_group_desc(sb, i, &bh);
flex_group = ext4_flex_group(sbi, i);
- sbi->s_flex_groups[flex_group].free_inodes +=
- ext4_free_inodes_count(sb, gdp);
- sbi->s_flex_groups[flex_group].free_blocks +=
- ext4_free_blks_count(sb, gdp);
+ atomic_set(&sbi->s_flex_groups[flex_group].free_inodes,
+ ext4_free_inodes_count(sb, gdp));
+ atomic_set(&sbi->s_flex_groups[flex_group].free_blocks,
+ ext4_free_blks_count(sb, gdp));
}
return 1;
--
1.5.6.3
--
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