Re: [PATCH 2/3] Use one zonelist that is filtered instead of multiplezonelists

From: Christoph Lameter
Date: Wed Aug 08 2007 - 13:46:54 EST


On Wed, 8 Aug 2007, Mel Gorman wrote:

> for (i = 0; i < npmem_ranges; i++) {
> + zl = &NODE_DATA(i)->node_zonelist;

The above shows up again and again. Maybe add a new inline function?

struct zonelist *zonelist_node(int node)


> {
> - return NODE_DATA(0)->node_zonelists + gfp_zone(gfp_flags);
> + return &NODE_DATA(0)->node_zonelist;

How many callers of gfp_zone are left? Do we still need the function?

Note that the memoryless_node patchset modifies gfp_zone and adds some
more zonelists (sigh).

> diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.23-rc1-mm2-005_freepages_zonelist/mm/oom_kill.c linux-2.6.23-rc1-mm2-010_use_zonelist/mm/oom_kill.c
> --- linux-2.6.23-rc1-mm2-005_freepages_zonelist/mm/oom_kill.c 2007-08-07 14:45:11.000000000 +0100
> +++ linux-2.6.23-rc1-mm2-010_use_zonelist/mm/oom_kill.c 2007-08-08 11:35:09.000000000 +0100
> @@ -177,8 +177,10 @@ static inline int constrained_alloc(stru
> {
> #ifdef CONFIG_NUMA
> struct zone **z;
> + struct zone *zone;
> nodemask_t nodes;
> int node;
> + enum zone_type high_zoneidx = gfp_zone(gfp_mask);
>
> nodes_clear(nodes);
> /* node has memory ? */
> @@ -186,9 +188,9 @@ static inline int constrained_alloc(stru
> if (NODE_DATA(node)->node_present_pages)
> node_set(node, nodes);
>
> - for (z = zonelist->zones; *z; z++)
> - if (cpuset_zone_allowed_softwall(*z, gfp_mask))
> - node_clear(zone_to_nid(*z), nodes);
> + for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
> + if (cpuset_zone_allowed_softwall(zone, gfp_mask))
> + node_clear(zone_to_nid(zone), nodes);
> else
> return CONSTRAINT_CPUSET;
>

The above portion has already been changed to no longer use a zonelist by
the memoryless_node patchset in mm.

> + zonelist = &NODE_DATA(slab_node(current->mempolicy))->node_zonelist;
> + for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
> struct kmem_cache_node *n;
>
> - n = get_node(s, zone_to_nid(*z));
> + n = get_node(s, zone_to_nid(zone));

Encoding the node in the zonelist pointer would help these loops but they
are fallback lists and not on the critical path.


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