AcoSail/kernel_optimize_test
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reduce m_start() cost...

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-02-27 14:40:10 -05:00
parent f2ebb3a921
commit c7999c3627
3 changed files with 23 additions and 4 deletions
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5
fs/mount.h
View File

@ -10,7 +10,7 @@ struct mnt_namespace {
struct user_namespace *user_ns;
u64 seq; /* Sequence number to prevent loops */
wait_queue_head_t poll;
int event;
u64 event;
};
struct mnt_pcp {
@ -104,6 +104,9 @@ struct proc_mounts {
struct mnt_namespace *ns;
struct path root;
int (*show)(struct seq_file *, struct vfsmount *);
void *cached_mount;
u64 cached_event;
loff_t cached_index;
};
#define proc_mounts(p) (container_of((p), struct proc_mounts, m))

21
fs/namespace.c
View File

@ -52,7 +52,7 @@ static int __init set_mphash_entries(char *str)
}
__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 @@ static void *m_start(struct seq_file *m, loff_t *pos)
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)

1
fs/proc_namespace.c
View File

@ -267,6 +267,7 @@ static int mounts_open_common(struct inode *inode, struct file *file,
p->root = root;
p->m.poll_event = ns->event;
p->show = show;
p->cached_event = ~0ULL;
return 0;