[PATCH] populated_map: fix !NUMA case, remove comment

[Nishanth Aravamudan <nacc@us.ibm.com>]

On 11.06.2007 [16:45:30 -0700], Christoph Lameter wrote:
> On Mon, 11 Jun 2007, Nishanth Aravamudan wrote:
> 
> > Eep, except that we don't initialize node_populated_mask unless we're
> > NUMA. Also, do you think it's worth adding the comment in mmzone.h that
> > now now NUMA policies depend on present_pages?
> 
> No need to initialize if we do not use it. You may to #ifdef it out
> by moving the definition. Please sent a diff against the earlier patch 
> since Andrew already merged it.

We will be using it (it == node_populated_mask) later in my sysfs patch
and in the fix hugepage allocation patch.

Sorry, sent the updated patch before I got Andrew's mail.

> present_pages just indicates that there is memory on the node. So I am not 
> sure that this will help.

Ok.

> > +
> > +	/*
> > +	 * record populated zones for use when INTERLEAVE'ing or using
> > +	 * GFP_THISNODE
> > +	 */
> 
> There may be other purposes as well. No need to enumerate those here.

Ok.

Applies on top of add-populated_map-to-account-for-memoryless-nodes.patch.

populated_map needs to be consistent in both the NUMA and !NUMA cases to
fix hugepage allocation with empty nodes. Assume the one node in the
!NUMA case is populated.

Remove a comment that would only increase the maintenance burden.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 456f2f6..825d2df 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2303,10 +2303,6 @@ static void build_zonelists(pg_data_t *pgdat)
 		build_zonelists_in_zone_order(pgdat, j);
 	}
 
-	/*
-	 * record populated zones for use when INTERLEAVE'ing or using
-	 * GFP_THISNODE
-	 */
 	if (pgdat->node_present_pages)
 		node_set_populated(local_node);
 }
@@ -2370,6 +2366,8 @@ static void build_zonelists(pg_data_t *pgdat)
 
 		zonelist->zones[j] = NULL;
 	}
+
+	node_set_populated(local_node);
 }
 
 /* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */

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