Avoids cache line ping pongs between cpus and prepare next patch,
because updates of nr_inodes metric dont need inode_lock anymore.
(socket8 bench result : 25s to 20.5s)
Signed-off-by: Eric Dumazet <dada1@xxxxxxxxxxxxx>
---
fs/fs-writeback.c | 2 -
fs/inode.c | 51 +++++++++++++++++++++++++++++++++++-------
include/linux/fs.h | 3 ++
kernel/sysctl.c | 4 +--
mm/page-writeback.c | 2 -
5 files changed, 50 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 d850050..8d8d40e 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -96,9 +96,40 @@ static DEFINE_MUTEX(iprune_mutex);
* Statistics gathering..
*/
struct inodes_stat_t inodes_stat;
+static DEFINE_PER_CPU(int, nr_inodes);
static struct kmem_cache * inode_cachep __read_mostly;
+int get_nr_inodes(void)
+{
+ int cpu;
+ int counter = 0;
+
+ for_each_possible_cpu(cpu)
+ counter += per_cpu(nr_inodes, cpu);
+ if (counter < 0)
+ counter = 0;
+ return counter;
+}
+
+/*
+ * Handle nr_dentry sysctl
+ */
+#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 +337,8 @@ 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);
+ get_cpu_var(nr_inodes) -= nr_disposed;
+ put_cpu_var(nr_inodes);
}
/*
@@ -584,10 +614,11 @@ struct inode *new_inode(struct super_block *sb)
inode = alloc_inode(sb);
if (inode) {
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);
+ get_cpu_var(nr_inodes)--;
inode->i_ino = last_ino_get();
+ put_cpu_var(nr_inodes);
inode->i_state = 0;
spin_unlock(&inode_lock);
}
@@ -645,7 +676,8 @@ 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++;
+ get_cpu_var(nr_inodes)++;
+ put_cpu_var(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);
@@ -694,7 +726,8 @@ 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++;
+ get_cpu_var(nr_inodes)++;
+ put_cpu_var(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);
@@ -1065,8 +1098,9 @@ 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);
+ get_cpu_var(nr_inodes)--;
+ put_cpu_var(nr_inodes);
security_inode_delete(inode);
@@ -1116,8 +1150,9 @@ 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);
+ get_cpu_var(nr_inodes)--;
+ put_cpu_var(nr_inodes);
if (inode->i_data.nrpages)
truncate_inode_pages(&inode->i_data, 0);
clear_inode(inode);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c5e7aa5..2482977 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;
@@ -2218,6 +2219,8 @@ 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 eebddef..eebed01 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1202,7 +1202,7 @@ 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,
@@ -1210,7 +1210,7 @@ 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;
