From 9f24e4208f7ee2748f157368b63287dc903fcf60 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 4 Mar 2009 19:09:10 -0500 Subject: 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/ialloc.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) (limited to 'fs/ext4/ialloc.c') 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 @@ 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(); -- cgit v1.2.3