Now that we have per-sb shrinkers, it makes sense to have nr_dentries
stored per sb as well. We turn them into per-cpu counters so we can
keep acessing them without locking.
Signed-off-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
CC: Dave Chinner <david@xxxxxxxxxxxxx>
---
fs/dcache.c | 18 ++++++++++--------
fs/super.c | 2 ++
include/linux/fs.h | 2 ++
3 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index b05aac3..9cb6395 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -115,16 +115,18 @@ struct dentry_stat_t dentry_stat = {
.age_limit = 45,
};
-static DEFINE_PER_CPU(unsigned int, nr_dentry);
-
#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
+static void super_nr_dentry(struct super_block *sb, void *arg)
+{
+ int *dentries = arg;
+ *dentries += percpu_counter_sum_positive(&sb->s_nr_dentry);
+}
+
static int get_nr_dentry(void)
{
- int i;
int sum = 0;
- for_each_possible_cpu(i)
- sum += per_cpu(nr_dentry, i);
- return sum < 0 ? 0 : sum;
+ iterate_supers(super_nr_dentry, &sum);
+ return sum;
}
int proc_nr_dentry(ctl_table *table, int write, void __user *buffer,
@@ -151,7 +153,7 @@ static void __d_free(struct rcu_head *head)
static void d_free(struct dentry *dentry)
{
BUG_ON(dentry->d_count);
- this_cpu_dec(nr_dentry);
+ percpu_counter_dec(&dentry->d_sb->s_nr_dentry);
if (dentry->d_op && dentry->d_op->d_release)
dentry->d_op->d_release(dentry);
@@ -1225,7 +1227,7 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
INIT_LIST_HEAD(&dentry->d_u.d_child);
d_set_d_op(dentry, dentry->d_sb->s_d_op);
- this_cpu_inc(nr_dentry);
+ percpu_counter_inc(&dentry->d_sb->s_nr_dentry);
return dentry;
}
diff --git a/fs/super.c b/fs/super.c
index 3f56a26..b16d8e8 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -183,6 +183,8 @@ static struct super_block *alloc_super(struct file_system_type *type)
s->s_shrink.seeks = DEFAULT_SEEKS;
s->s_shrink.shrink = prune_super;
s->s_shrink.batch = 1024;
+
+ percpu_counter_init(&s->s_nr_dentry, 0);
}
out:
return s;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f23bcb7..8150f52 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1399,6 +1399,8 @@ struct super_block {
struct list_head s_dentry_lru; /* unused dentry lru */
int s_nr_dentry_unused; /* # of dentry on lru */
+ struct percpu_counter s_nr_dentry; /* # of dentry on this sb */
+
/* s_inode_lru_lock protects s_inode_lru and s_nr_inodes_unused */
spinlock_t s_inode_lru_lock ____cacheline_aligned_in_smp;
struct list_head s_inode_lru; /* unused inode lru */
--
1.7.6
--
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