Re: [PATCH] use vmalloc for mem_cgroup allocation. v2

[Harvey Harrison]

On Mon, 2008-04-14 at 19:20 -0700, Andrew Morton wrote:
> On Tue, 15 Apr 2008 10:08:25 +0800 Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:
> 
> > > @@ -992,8 +993,10 @@ mem_cgroup_create(struct cgroup_subsys *
> > >  	if (unlikely((cont->parent) == NULL)) {
> > >  		mem = &init_mem_cgroup;
> > >  		page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
> > > -	} else
> > > -		mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
> > > +	} else {
> > > +		mem = vmalloc(sizeof(struct mem_cgroup));
> > > +		memset(mem, 0, sizeof(*mem));
> > 
> > what if mem == NULL. ;)
> > 
> > > +	}
> > >  
> > >  	if (mem == NULL)
> > >  		return ERR_PTR(-ENOMEM);
> > 
> > So we can move this NULL check to the above else branch, in the if brach,
> > mem won't be NULL.
> 
> err, yes.
> 
> So I have:
> 
> 	if (unlikely((cont->parent) == NULL)) {

	if (unlikely(cont->parent == NULL)) {

> 		mem = &init_mem_cgroup;
> 		page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
> 	} else {
> 		mem = vmalloc(sizeof(struct mem_cgroup));
> 		if (mem == NULL)

		if (!mem)

> 			return ERR_PTR(-ENOMEM);
> 		memset(mem, 0, sizeof(*mem));
> 	}
> 

Cheers,

Harvey


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