Re: Dropped patch: mm/mempolicy.c:sp_lookup()

[Andi Kleen <ak@suse.de>]

> Some optimizations in mempolicy.c (like to avoid rebalancing the tree while
> destroying it and by breaking loops early and not checking for invariant
> conditions in the replace operation).

[...]
> 
> diff -puN mm/mempolicy.c~mempolicy-optimization mm/mempolicy.c
> --- 25/mm/mempolicy.c~mempolicy-optimization	2004-11-17 12:26:40.149947024 -0800
> +++ 25-akpm/mm/mempolicy.c	2004-11-17 12:26:40.153946416 -0800
> @@ -1211,12 +1211,10 @@ restart:
>  						return -ENOMEM;
>  					goto restart;
>  				}
> -				n->end = end;
> +				n->end = start;
>  				sp_insert(sp, new2);
> -				new2 = NULL;
> -			}
> -			/* Old crossing beginning, but not end (easy) */
> -			if (n->start < start && n->end > start)
> +				break;
> +			} else
>  				n->end = start;
>  		}
>  		if (!next)

I'm not quite sure about this one.

> @@ -1270,11 +1268,11 @@ void mpol_free_shared_policy(struct shar
>  	while (next) {
>  		n = rb_entry(next, struct sp_node, nd);
>  		next = rb_next(&n->nd);
> -		rb_erase(&n->nd, &p->root);
>  		mpol_free(n->policy);
>  		kmem_cache_free(sn_cache, n);
>  	}
>  	spin_unlock(&p->lock);
> +	p->root = RB_ROOT;
>  }

This hunk is fine.

-Andi