From: Eric Dumazet Avoids cache line ping pongs between cpus and prepare next patch, because updates of nr_inodes dont need inode_lock anymore. Signed-off-by: Eric Dumazet Signed-off-by: Nick Piggin --- fs/fs-writeback.c | 4 ++-- fs/inode.c | 31 ++++++++++++++++++++++++++++--- include/linux/fs.h | 5 ++++- kernel/sysctl.c | 4 ++-- 4 files changed, 36 insertions(+), 8 deletions(-) Index: linux-2.6/fs/fs-writeback.c =================================================================== --- linux-2.6.orig/fs/fs-writeback.c +++ linux-2.6/fs/fs-writeback.c @@ -904,7 +904,7 @@ static long wb_check_old_data_flush(stru wb->last_old_flush = jiffies; nr_pages = global_page_state(NR_FILE_DIRTY) + global_page_state(NR_UNSTABLE_NFS) + - inodes_stat.nr_inodes - inodes_stat.nr_unused; + get_nr_inodes() - inodes_stat.nr_unused; if (nr_pages) { struct wb_writeback_args args = { @@ -1257,7 +1257,7 @@ void writeback_inodes_sb(struct super_bl long nr_to_write; nr_to_write = nr_dirty + nr_unstable + - inodes_stat.nr_inodes - inodes_stat.nr_unused; + get_nr_inodes() - inodes_stat.nr_unused; bdi_start_writeback(sb->s_bdi, sb, nr_to_write); } Index: linux-2.6/fs/inode.c =================================================================== --- linux-2.6.orig/fs/inode.c +++ linux-2.6/fs/inode.c @@ -144,9 +144,33 @@ struct inodes_stat_t inodes_stat = { .nr_inodes = 0, .nr_unused = 0, }; +struct percpu_counter nr_inodes; static struct kmem_cache *inode_cachep __read_mostly; +int get_nr_inodes(void) +{ + return percpu_counter_sum_positive(&nr_inodes); +} + +/* + * Handle nr_dentry sysctl + */ +#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) +int proc_nr_inodes(ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + inodes_stat.nr_inodes = get_nr_inodes(); + return proc_dointvec(table, write, buffer, lenp, ppos); +} +#else +int proc_nr_inodes(ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + return -ENOSYS; +} +#endif + static void wake_up_inode(struct inode *inode) { /* @@ -657,8 +681,8 @@ __inode_add_to_lists(struct super_block { spin_lock(&sb_inode_list_lock); list_add_rcu(&inode->i_sb_list, &sb->s_inodes); - inodes_stat.nr_inodes++; spin_unlock(&sb_inode_list_lock); + percpu_counter_inc(&nr_inodes); if (b) { spin_lock_bucket(b); hlist_bl_add_head_rcu(&inode->i_hash, &b->head); @@ -1337,8 +1361,8 @@ void generic_delete_inode(struct inode * } spin_lock(&sb_inode_list_lock); list_del_rcu(&inode->i_sb_list); - inodes_stat.nr_inodes--; spin_unlock(&sb_inode_list_lock); + percpu_counter_dec(&nr_inodes); WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; spin_unlock(&inode->i_lock); @@ -1413,8 +1437,8 @@ int generic_detach_inode(struct inode *i } spin_lock(&sb_inode_list_lock); list_del_rcu(&inode->i_sb_list); - inodes_stat.nr_inodes--; spin_unlock(&sb_inode_list_lock); + percpu_counter_dec(&nr_inodes); WARN_ON(inode->i_state & I_NEW); inode->i_state |= I_FREEING; spin_unlock(&inode->i_lock); @@ -1723,6 +1747,7 @@ void __init inode_init(void) { int loop; + percpu_counter_init(&nr_inodes, 0); /* inode slab cache */ inode_cachep = kmem_cache_create("inode_cache", sizeof(struct inode), Index: linux-2.6/include/linux/fs.h =================================================================== --- linux-2.6.orig/include/linux/fs.h +++ linux-2.6/include/linux/fs.h @@ -406,6 +406,8 @@ extern struct files_stat_struct files_st extern int get_max_files(void); extern int sysctl_nr_open; extern struct inodes_stat_t inodes_stat; +extern struct percpu_counter nr_inodes; +extern int get_nr_inodes(void); extern int leases_enable, lease_break_time; #ifdef CONFIG_DNOTIFY extern int dir_notify_enable; @@ -2514,7 +2516,8 @@ ssize_t simple_attr_write(struct file *f struct ctl_table; int proc_nr_files(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); - +int proc_nr_inodes(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos); int __init get_filesystem_list(char *buf); #define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE]) Index: linux-2.6/kernel/sysctl.c =================================================================== --- linux-2.6.orig/kernel/sysctl.c +++ linux-2.6/kernel/sysctl.c @@ -1338,14 +1338,14 @@ static struct ctl_table fs_table[] = { .data = &inodes_stat, .maxlen = 2*sizeof(int), .mode = 0444, - .proc_handler = proc_dointvec, + .proc_handler = proc_nr_inodes, }, { .procname = "inode-state", .data = &inodes_stat, .maxlen = 7*sizeof(int), .mode = 0444, - .proc_handler = proc_dointvec, + .proc_handler = proc_nr_inodes, }, { .procname = "file-nr", -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/