[PATCH 3/3] memblock: Make find_memory_core_early() find from top-down

From: Yinghai Lu
Date: Fri Dec 17 2010 - 20:01:28 EST



That is used for find ram in node or bootmem type.

We should make it top-down so it will be consistent to memblock_find.

Suggested-by: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

---
mm/page_alloc.c | 34 +++++++++++++++++++++++++++++++++-
1 file changed, 33 insertions(+), 1 deletion(-)

Index: linux-2.6/mm/page_alloc.c
===================================================================
--- linux-2.6.orig/mm/page_alloc.c
+++ linux-2.6/mm/page_alloc.c
@@ -3556,6 +3556,34 @@ static int __meminit next_active_region_
return -1;
}

+/*
+ * Basic iterator support. Return the last range of PFNs for a node
+ * Note: nid == MAX_NUMNODES returns last region regardless of node
+ */
+static int __meminit last_active_region_index_in_nid(int nid)
+{
+ int i;
+
+ for (i = nr_nodemap_entries - 1; i >= 0; i--)
+ if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
+ return i;
+
+ return -1;
+}
+
+/*
+ * Basic iterator support. Return the previous active range of PFNs for a node
+ * Note: nid == MAX_NUMNODES returns next region regardless of node
+ */
+static int __meminit previous_active_region_index_in_nid(int index, int nid)
+{
+ for (index = index - 1; index >= 0; index--)
+ if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
+ return index;
+
+ return -1;
+}
+
#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
/*
* Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
@@ -3607,6 +3635,10 @@ bool __meminit early_pfn_in_nid(unsigned
for (i = first_active_region_index_in_nid(nid); i != -1; \
i = next_active_region_index_in_nid(i, nid))

+#define for_each_active_range_index_in_nid_reverse(i, nid) \
+ for (i = last_active_region_index_in_nid(nid); i != -1; \
+ i = previous_active_region_index_in_nid(i, nid))
+
/**
* free_bootmem_with_active_regions - Call free_bootmem_node for each active range
* @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
@@ -3645,7 +3677,7 @@ u64 __init find_memory_core_early(int ni
int i;

/* Need to go over early_node_map to find out good range for node */
- for_each_active_range_index_in_nid(i, nid) {
+ for_each_active_range_index_in_nid_reverse(i, nid) {
u64 addr;
u64 ei_start, ei_last;
u64 final_start, final_end;
--
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