[PATCH] NUMA meminfo for driverfs Topology

From Matthew Dobson.

Create nodeX/meminfo files for DriverFS Topology.

This patch adds code to DriverFS Topology to expose per-node memory
statistics.  This information is exposed via: cat nodeX/meminfo

The patch also adds 2 helper functions to gather per-node memory info.

drivers/base/node.c

@@ -35,6 +35,34 @@ static ssize_t node_read_cpumap(struct device * dev, char * buf, size_t count, l
 }
 static DEVICE_ATTR(cpumap,S_IRUGO,node_read_cpumap,NULL);
 
+#define K(x) ((x) << (PAGE_SHIFT - 10))
+static ssize_t node_read_meminfo(struct device * dev, char * buf, size_t count, loff_t off)
+{
+	struct sys_root *node = to_root(dev);
+	int nid = node->id;
+	struct sysinfo i;
+	si_meminfo_node(&i, nid);
+	return off ? 0 : sprintf(buf, "\n"
+			"Node %d MemTotal:     %8lu kB\n"
+			"Node %d MemFree:      %8lu kB\n"
+			"Node %d MemUsed:      %8lu kB\n"
+			"Node %d HighTotal:    %8lu kB\n"
+			"Node %d HighFree:     %8lu kB\n"
+			"Node %d LowTotal:     %8lu kB\n"
+			"Node %d LowFree:      %8lu kB\n",
+			nid, K(i.totalram),
+			nid, K(i.freeram),
+			nid, K(i.totalram-i.freeram),
+			nid, K(i.totalhigh),
+			nid, K(i.freehigh),
+			nid, K(i.totalram-i.totalhigh),
+			nid, K(i.freeram-i.freehigh));
+
+	return 0;
+}
+#undef K 
+static DEVICE_ATTR(meminfo,S_IRUGO,node_read_meminfo,NULL);
+
 
 /*
  * register_node - Setup a driverfs device for a node.
@@ -54,6 +82,7 @@ void __init register_node(struct node *node, int num, struct node *parent)
 	node->sysroot.dev.bus = &system_bus_type;
 	if (!sys_register_root(&node->sysroot)){
 		device_create_file(&node->sysroot.dev, &dev_attr_cpumap);
+		device_create_file(&node->sysroot.dev, &dev_attr_meminfo);
 	}
 }
 

include/linux/mm.h

@@ -439,6 +439,9 @@ extern void free_area_init_node(int nid, pg_data_t *pgdat, struct page *pmap,
 extern void mem_init(void);
 extern void show_mem(void);
 extern void si_meminfo(struct sysinfo * val);
+#ifdef CONFIG_NUMA
+extern void si_meminfo_node(struct sysinfo *val, int nid);
+#endif
 extern void swapin_readahead(swp_entry_t);
 
 extern int can_share_swap_page(struct page *);

include/linux/swap.h

@@ -131,6 +131,9 @@ extern int nr_swap_pages;
 extern unsigned long totalram_pages;
 extern unsigned long totalhigh_pages;
 extern unsigned int nr_free_pages(void);
+#ifdef CONFIG_NUMA
+extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat);
+#endif
 extern unsigned int nr_free_buffer_pages(void);
 extern unsigned int nr_free_pagecache_pages(void);
 

mm/page_alloc.c

@@ -595,6 +595,18 @@ unsigned int nr_used_zone_pages(void)
 	return pages;
 }
 
+#ifdef CONFIG_NUMA
+unsigned int nr_free_pages_pgdat(pg_data_t *pgdat)
+{
+	unsigned int i, sum = 0;
+
+	for (i = 0; i < MAX_NR_ZONES; i++)
+		sum += pgdat->node_zones[i].free_pages;
+
+	return sum;
+}
+#endif
+
 static unsigned int nr_free_zone_pages(int offset)
 {
 	pg_data_t *pgdat;
@@ -722,6 +734,19 @@ void si_meminfo(struct sysinfo *val)
 	val->mem_unit = PAGE_SIZE;
 }
 
+#ifdef CONFIG_NUMA
+void si_meminfo_node(struct sysinfo *val, int nid)
+{
+	pg_data_t *pgdat = NODE_DATA(nid);
+
+	val->totalram = pgdat->node_size;
+	val->freeram = nr_free_pages_pgdat(pgdat);
+	val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].spanned_pages;
+	val->freehigh = pgdat->node_zones[ZONE_HIGHMEM].free_pages;
+	val->mem_unit = PAGE_SIZE;
+}
+#endif
+
 #define K(x) ((x) << (PAGE_SHIFT-10))
 
 /*