[CRIU] [PATCH] mnt: Shorten the mntns dumping loop

[Andrew Vagin]

On Mon, Sep 22, 2014 at 04:26:44PM +0400, Pavel wrote:
> We currently have all mouninfo-s from all mnt namespaces collected
> in one big list. On dump we scan through it to find the namespaces
> we need to dump.
> 
> This can be optimized by walking the list of namespaces instead.

Acked-by: Andrew Vagin <avagin at parallels.com>
> 
> Signed-off-by: Pavel Emelyanov <xemul at parallels.com>
> ---
>  include/namespaces.h |  1 +
>  mount.c              | 14 ++++++--------
>  2 files changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/include/namespaces.h b/include/namespaces.h
> index 350b8b4..ccf55f8 100644
> --- a/include/namespaces.h
> +++ b/include/namespaces.h
> @@ -18,6 +18,7 @@ struct ns_id {
>  	futex_t created; /* boolean */
>  	union {
>  		struct {
> +			struct mount_info *mntinfo_list;
>  			struct mount_info *mntinfo_tree;
>  		} mnt;
>  	};
> diff --git a/mount.c b/mount.c
> index fb3fe6b..685f340 100644
> --- a/mount.c
> +++ b/mount.c
> @@ -975,7 +975,7 @@ struct mount_info *collect_mntinfo(struct ns_id *ns)
>  {
>  	struct mount_info *pm;
>  
> -	pm = parse_mountinfo(ns->pid, ns);
> +	ns->mnt.mntinfo_list = pm = parse_mountinfo(ns->pid, ns);
>  	if (!pm) {
>  		pr_err("Can't parse %d's mountinfo\n", ns->pid);
>  		return NULL;
> @@ -2133,15 +2133,14 @@ int collect_mnt_namespaces(void)
>  
>  int dump_mnt_namespaces(void)
>  {
> -	struct ns_id *nsid = NULL;
> -	struct mount_info *m;
> +	struct ns_id *nsid;
>  	int n = 0;
>  
>  	if (!(root_ns_mask & CLONE_NEWNS))
>  		return 0;
>  
> -	for (m = mntinfo; m; m = m->next) {
> -		if (m->nsid == nsid)
> +	for (nsid = ns_ids; nsid != NULL; nsid = nsid->next) {
> +		if (nsid->nd != &mnt_ns_desc)
>  			continue;
>  
>  		if (++n == 2 && check_mnt_id()) {
> @@ -2150,11 +2149,10 @@ int dump_mnt_namespaces(void)
>  			return -1;
>  		}
>  
> -		if (dump_mnt_ns(m->nsid, m))
> +		if (dump_mnt_ns(nsid, nsid->mnt.mntinfo_list))
>  			return -1;
> -
> -		nsid = m->nsid;
>  	}
> +
>  	return 0;
>  }
>  
> -- 
> 1.8.4.2
> 
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