On Thu, Dec 11, 2008 at 11:39:10PM +0100, Eric Dumazet wrote: > Avoids cache line ping pongs between cpus and prepare next patch, > because updates of nr_inodes dont need inode_lock anymore. > > (socket8 bench result : no difference at this point)
I do like this per-CPU counter infrastructure! One small comment change noted below. Other than that: Reviewed-by: Paul E. McKenney <[email protected]> > Signed-off-by: Eric Dumazet <[email protected]> > --- > fs/fs-writeback.c | 2 +- > fs/inode.c | 39 +++++++++++++++++++++++++++++++-------- > include/linux/fs.h | 3 +++ > kernel/sysctl.c | 4 ++-- > mm/page-writeback.c | 2 +- > 5 files changed, 38 insertions(+), 12 deletions(-) > > > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c > index d0ff0b8..b591cdd 100644 > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -608,7 +608,7 @@ void sync_inodes_sb(struct super_block *sb, int wait) > unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); > > wbc.nr_to_write = nr_dirty + nr_unstable + > - (inodes_stat.nr_inodes - inodes_stat.nr_unused) + > + (get_nr_inodes() - inodes_stat.nr_unused) + > nr_dirty + nr_unstable; > wbc.nr_to_write += wbc.nr_to_write / 2; /* Bit more for luck */ > sync_sb_inodes(sb, &wbc); > diff --git a/fs/inode.c b/fs/inode.c > index 0487ddb..f94f889 100644 > --- a/fs/inode.c > +++ b/fs/inode.c > @@ -96,9 +96,33 @@ static DEFINE_MUTEX(iprune_mutex); > * Statistics gathering.. > */ > struct inodes_stat_t inodes_stat; > +static 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 That would be "nr_inode", right? > + */ > +#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) > +int proc_nr_inodes(ctl_table *table, int write, struct file *filp, > + void __user *buffer, size_t *lenp, loff_t *ppos) > +{ > + inodes_stat.nr_inodes = get_nr_inodes(); > + return proc_dointvec(table, write, filp, buffer, lenp, ppos); > +} > +#else > +int proc_nr_inodes(ctl_table *table, int write, struct file *filp, > + void __user *buffer, size_t *lenp, loff_t *ppos) > +{ > + return -ENOSYS; > +} > +#endif > + > static void wake_up_inode(struct inode *inode) > { > /* > @@ -306,9 +330,7 @@ static void dispose_list(struct list_head *head) > destroy_inode(inode); > nr_disposed++; > } > - spin_lock(&inode_lock); > - inodes_stat.nr_inodes -= nr_disposed; > - spin_unlock(&inode_lock); > + percpu_counter_sub(&nr_inodes, nr_disposed); > } > > /* > @@ -560,8 +582,8 @@ struct inode *new_inode(struct super_block *sb) > > inode = alloc_inode(sb); > if (inode) { > + percpu_counter_inc(&nr_inodes); > spin_lock(&inode_lock); > - inodes_stat.nr_inodes++; > list_add(&inode->i_list, &inode_in_use); > list_add(&inode->i_sb_list, &sb->s_inodes); > inode->i_ino = ++last_ino; > @@ -622,7 +644,7 @@ static struct inode * get_new_inode(struct super_block > *sb, struct hlist_head *h > if (set(inode, data)) > goto set_failed; > > - inodes_stat.nr_inodes++; > + percpu_counter_inc(&nr_inodes); > list_add(&inode->i_list, &inode_in_use); > list_add(&inode->i_sb_list, &sb->s_inodes); > hlist_add_head(&inode->i_hash, head); > @@ -671,7 +693,7 @@ static struct inode * get_new_inode_fast(struct > super_block *sb, struct hlist_he > old = find_inode_fast(sb, head, ino); > if (!old) { > inode->i_ino = ino; > - inodes_stat.nr_inodes++; > + percpu_counter_inc(&nr_inodes); > list_add(&inode->i_list, &inode_in_use); > list_add(&inode->i_sb_list, &sb->s_inodes); > hlist_add_head(&inode->i_hash, head); > @@ -1042,8 +1064,8 @@ void generic_delete_inode(struct inode *inode) > list_del_init(&inode->i_list); > list_del_init(&inode->i_sb_list); > inode->i_state |= I_FREEING; > - inodes_stat.nr_inodes--; > spin_unlock(&inode_lock); > + percpu_counter_dec(&nr_inodes); > > security_inode_delete(inode); > > @@ -1093,8 +1115,8 @@ static void generic_forget_inode(struct inode *inode) > list_del_init(&inode->i_list); > list_del_init(&inode->i_sb_list); > inode->i_state |= I_FREEING; > - inodes_stat.nr_inodes--; > spin_unlock(&inode_lock); > + percpu_counter_dec(&nr_inodes); > if (inode->i_data.nrpages) > truncate_inode_pages(&inode->i_data, 0); > clear_inode(inode); > @@ -1394,6 +1416,7 @@ 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), > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 114cb65..a789346 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -47,6 +47,7 @@ struct inodes_stat_t { > int dummy[5]; /* padding for sysctl ABI compatibility */ > }; > extern struct inodes_stat_t inodes_stat; > +extern int get_nr_inodes(void); > > extern int leases_enable, lease_break_time; > > @@ -2219,6 +2220,8 @@ int proc_nr_files(struct ctl_table *table, int write, > struct file *filp, > void __user *buffer, size_t *lenp, loff_t *ppos); > int proc_nr_dentry(struct ctl_table *table, int write, struct file *filp, > void __user *buffer, size_t *lenp, loff_t *ppos); > +int proc_nr_inodes(struct ctl_table *table, int write, struct file *filp, > + void __user *buffer, size_t *lenp, loff_t *ppos); > > int get_filesystem_list(char * buf); > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 777bee7..b705f3a 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -1205,7 +1205,7 @@ static struct ctl_table fs_table[] = { > .data = &inodes_stat, > .maxlen = 2*sizeof(int), > .mode = 0444, > - .proc_handler = &proc_dointvec, > + .proc_handler = &proc_nr_inodes, > }, > { > .ctl_name = FS_STATINODE, > @@ -1213,7 +1213,7 @@ static struct ctl_table fs_table[] = { > .data = &inodes_stat, > .maxlen = 7*sizeof(int), > .mode = 0444, > - .proc_handler = &proc_dointvec, > + .proc_handler = &proc_nr_inodes, > }, > { > .procname = "file-nr", > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index 2970e35..a71a922 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -705,7 +705,7 @@ static void wb_kupdate(unsigned long arg) > next_jif = start_jif + dirty_writeback_interval; > nr_to_write = 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); > while (nr_to_write > 0) { > wbc.more_io = 0; > wbc.encountered_congestion = 0; -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
