From 9f24e4208f7ee2748f157368b63287dc903fcf60 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 4 Mar 2009 19:09:10 -0500 Subject: [PATCH] ext4: Use atomic_t's in struct flex_groups 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" --- 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 b37b12875582..53c72ad85877 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 e5c273ff928b..e52b48f86ed4 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -170,8 +170,8 @@ 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 617f5a2d800a..5f393927fd25 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 @@ static int find_group_flex(struct super_block *sb, struct inode *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 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode) 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 c4c430977622..e72c72a0b807 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3044,9 +3044,8 @@ 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); @@ -4884,9 +4883,7 @@ void ext4_mb_free_blocks(handle_t *handle, struct inode *inode, 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 c06886abd658..546c7dd869e1 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 1ec554cc107a..6b5d5c6399fa 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1630,10 +1630,10 @@ 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;