[patch] GFP_ZONEMASK vs. MAX_NR_ZONES

Matthew Dobson (colpatch@us.ibm.com)
Mon, 17 Mar 2003 17:53:08 -0800


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Ok... hot on the heels of the other GFP_ZONEMASK patch:

struct bootmem_data;
typedef struct pglist_data {
struct zone node_zones[MAX_NR_ZONES];
struct zonelist node_zonelists[GFP_ZONEMASK+1];
int nr_zones;
struct page *node_mem_map;
unsigned long *valid_addr_bitmap;
struct bootmem_data *bdata;
unsigned long node_start_pfn;
unsigned long node_size;
int node_id;
struct pglist_data *pgdat_next;
wait_queue_head_t kswapd_wait;
} pg_data_t;

node_zonelists looks like it should really be declared of size
MAX_NR_ZONES, not GFP_ZONEMASK. GFP_ZONEMASK is currently 15, making
node_zonelists an array of 16 elements. The extra zonelists are all
just duplicates of the *real* zonelists, namely the first 3 entries.
Again, if anyone can explain to me why I'm wrong in my thinking, I'd
love to know. There's certainly no way you could bitwise-and something
with any combination of the GFP_DMA and GFP_HIGHMEM flags to refer to
the 12th zonelist or some such! Or am I crazy?

Cheers!

-Matt

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diff -Nur --exclude-from=/usr/src/.dontdiff linux-2.5.64-vanilla/include/linux/mmzone.h linux-2.5.64-zonelist_fix/include/linux/mmzone.h
--- linux-2.5.64-vanilla/include/linux/mmzone.h Tue Mar 4 19:29:22 2003
+++ linux-2.5.64-zonelist_fix/include/linux/mmzone.h Mon Mar 17 14:13:02 2003
@@ -178,7 +178,7 @@
struct bootmem_data;
typedef struct pglist_data {
struct zone node_zones[MAX_NR_ZONES];
- struct zonelist node_zonelists[GFP_ZONEMASK+1];
+ struct zonelist node_zonelists[MAX_NR_ZONES];
int nr_zones;
struct page *node_mem_map;
unsigned long *valid_addr_bitmap;
diff -Nur --exclude-from=/usr/src/.dontdiff linux-2.5.64-vanilla/mm/page_alloc.c linux-2.5.64-zonelist_fix/mm/page_alloc.c
--- linux-2.5.64-vanilla/mm/page_alloc.c Tue Mar 4 19:28:58 2003
+++ linux-2.5.64-zonelist_fix/mm/page_alloc.c Mon Mar 17 14:13:02 2003
@@ -1028,7 +1028,7 @@

local_node = pgdat->node_id;
printk("Building zonelist for node : %d\n", local_node);
- for (i = 0; i <= GFP_ZONEMASK; i++) {
+ for (i = 0; i < MAX_NR_ZONES; i++) {
struct zonelist *zonelist;

zonelist = pgdat->node_zonelists + i;

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