reduce m_start() cost...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index 65233a5..a66aff5 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -52,7 +52,7 @@
}
__setup("mphash_entries=", set_mphash_entries);
-static int event;
+static u64 event;
static DEFINE_IDA(mnt_id_ida);
static DEFINE_IDA(mnt_group_ida);
static DEFINE_SPINLOCK(mnt_id_lock);
@@ -1100,14 +1100,29 @@
struct proc_mounts *p = proc_mounts(m);
down_read(&namespace_sem);
- return seq_list_start(&p->ns->list, *pos);
+ if (p->cached_event == p->ns->event) {
+ void *v = p->cached_mount;
+ if (*pos == p->cached_index)
+ return v;
+ if (*pos == p->cached_index + 1) {
+ v = seq_list_next(v, &p->ns->list, &p->cached_index);
+ return p->cached_mount = v;
+ }
+ }
+
+ p->cached_event = p->ns->event;
+ p->cached_mount = seq_list_start(&p->ns->list, *pos);
+ p->cached_index = *pos;
+ return p->cached_mount;
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
struct proc_mounts *p = proc_mounts(m);
- return seq_list_next(v, &p->ns->list, pos);
+ p->cached_mount = seq_list_next(v, &p->ns->list, pos);
+ p->cached_index = *pos;
+ return p->cached_mount;
}
static void m_stop(struct seq_file *m, void *v)