[PATCH 05/12] inode: convert inode_stat.nr_unused to per-cpu counters

Dave Chinner
2011-06-02T07:03:54Z

From: Dave Chinner <dchinner@redhat.com>

Before we split up the inode_lru_lock, the unused inode counter
needs to be made independent of the global inode_lru_lock. Convert
it to per-cpu counters to do this.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/inode.c | 16 +++++++++++-----
1 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 0f7e88a..17fea5b 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -95,6 +95,7 @@ EXPORT_SYMBOL(empty_aops);
struct inodes_stat_t inodes_stat;

static DEFINE_PER_CPU(unsigned int, nr_inodes);
+static DEFINE_PER_CPU(unsigned int, nr_unused);

static struct kmem_cache *inode_cachep __read_mostly;

@@ -109,7 +110,11 @@ static int get_nr_inodes(void)

static inline int get_nr_inodes_unused(void)
{
- return inodes_stat.nr_unused;
+ int i;
+ int sum = 0;
+ for_each_possible_cpu(i)
+ sum += per_cpu(nr_unused, i);
+ return sum < 0 ? 0 : sum;
}

int get_nr_dirty_inodes(void)
@@ -127,6 +132,7 @@ 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();
+ inodes_stat.nr_unused = get_nr_inodes_unused();
return proc_dointvec(table, write, buffer, lenp, ppos);
}
#endif
@@ -340,7 +346,7 @@ static void inode_lru_list_add(struct inode *inode)
spin_lock(&inode_lru_lock);
if (list_empty(&inode->i_lru)) {
list_add(&inode->i_lru, &inode_lru);
- inodes_stat.nr_unused++;
+ this_cpu_inc(nr_unused);
}
spin_unlock(&inode_lru_lock);
}
@@ -350,7 +356,7 @@ static void inode_lru_list_del(struct inode *inode)
spin_lock(&inode_lru_lock);
if (!list_empty(&inode->i_lru)) {
list_del_init(&inode->i_lru);
- inodes_stat.nr_unused--;
+ this_cpu_dec(nr_unused);
}
spin_unlock(&inode_lru_lock);
}
@@ -649,7 +655,7 @@ static void prune_icache(int nr_to_scan)
(inode->i_state & ~I_REFERENCED)) {
list_del_init(&inode->i_lru);
spin_unlock(&inode->i_lock);
- inodes_stat.nr_unused--;
+ this_cpu_dec(nr_unused);
continue;
}

@@ -686,7 +692,7 @@ static void prune_icache(int nr_to_scan)
spin_unlock(&inode->i_lock);

list_move(&inode->i_lru, &freeable);
- inodes_stat.nr_unused--;
+ this_cpu_dec(nr_unused);
}
if (current_is_kswapd())
__count_vm_events(KSWAPD_INODESTEAL, reap);
--
1.7.5.1