On Mon, Jun 18, 2007 at 02:02:19PM +0200, Cedric Le Goater wrote:
> 
> > on Linux-VServer,we have accounting for those
> > proxies (and several other namespace related stuff)
> > because we already suspected leakage and reference
> > bugs in this area some time ago ... btw, I also
> > suggested to put a similar functionality in mainline
> > for the time being, but it was ignored, as usual ...
> 
> something like a kmem_cache ? 

maybe, but even simplest accounting of the
different 'objects' would be more then enough
for the test phase (or maybe as statistics :)

> and we are not ignoring vserver ! :)

good for them, our project is called Linux-VServer :)

best,
Herbert

> Cheers,
> 
> C.
> 
> Add a kmem_cache to manage nsproxy objects. 
> 
> Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
> ---
>  kernel/nsproxy.c |   21 +++++++++++++++++----
>  1 file changed, 17 insertions(+), 4 deletions(-)
> 
> Index: 2.6.22-rc4-mm2/kernel/nsproxy.c
> ===================================================================
> --- 2.6.22-rc4-mm2.orig/kernel/nsproxy.c
> +++ 2.6.22-rc4-mm2/kernel/nsproxy.c
> @@ -21,6 +21,8 @@
>  #include <linux/utsname.h>
>  #include <linux/pid_namespace.h>
>  
> +static struct kmem_cache *nsproxy_cachep;
> +
>  struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
>  
>  static inline void get_nsproxy(struct nsproxy *ns)
> @@ -43,9 +45,11 @@ static inline struct nsproxy *clone_nspr
>  {
>  	struct nsproxy *ns;
>  
> -	ns = kmemdup(orig, sizeof(struct nsproxy), GFP_KERNEL);
> -	if (ns)
> +	ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
> +	if (ns) {
> +		memcpy(ns, orig, sizeof(struct nsproxy));
>  		atomic_set(&ns->count, 1);
> +	}
>  	return ns;
>  }
>  
> @@ -109,7 +113,7 @@ out_uts:
>  	if (new_nsp->mnt_ns)
>  		put_mnt_ns(new_nsp->mnt_ns);
>  out_ns:
> -	kfree(new_nsp);
> +	kmem_cache_free(nsproxy_cachep, new_nsp);
>  	return ERR_PTR(err);
>  }
>  
> @@ -160,7 +164,7 @@ void free_nsproxy(struct nsproxy *ns)
>  		put_pid_ns(ns->pid_ns);
>  	if (ns->user_ns)
>  		put_user_ns(ns->user_ns);
> -	kfree(ns);
> +	kmem_cache_free(nsproxy_cachep, ns);
>  }
>  
>  /*
> @@ -191,3 +195,12 @@ int unshare_nsproxy_namespaces(unsigned 
>  	}
>  	return err;
>  }
> +
> +static int __init nsproxy_cache_init(void)
> +{
> +	nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy),
> +					   0, SLAB_PANIC, NULL, NULL);
> +	return 0;
> +}
> +
> +module_init(nsproxy_cache_init);
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