remove_pgdat() is main code for pgdat removing.
remove_pgdat() should be called for node-hotremove, but nothing calls
it. Sysfs interface (or anything else?) will be necessary.
And current offline_pages() has to be update zonelist and N_HIGH_MEMORY
if there is no present_pages on the node, and stop kswapd().
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
---
mm/memory_hotplug.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 84 insertions(+), 1 deletion(-)
Index: current/mm/memory_hotplug.c
===================================================================
--- current.orig/mm/memory_hotplug.c 2008-07-29 22:17:24.000000000 +0900
+++ current/mm/memory_hotplug.c 2008-07-29 22:17:32.000000000 +0900
@@ -241,6 +241,82 @@ static int __add_section(struct zone *zo
return register_new_memory(__pfn_to_section(phys_start_pfn));
}
+static int cpus_busy_on_node(int nid)
+{
+ cpumask_t tmp = node_to_cpumask(nid);
+ int cpu, ret;
+
+ for_each_cpu_mask(cpu, tmp) {
+ if (cpu_online(cpu)) {
+ printk(KERN_INFO "cpu %d is busy\n", cpu);
+ ret = 1 ;
+ }
+ }
+ return 0;
+}
+
+static int sections_busy_on_node(struct pglist_data *pgdat)
+{
+ unsigned long section_nr, num, i;
+ int ret = 0;
+
+ section_nr = pfn_to_section_nr(pgdat->node_start_pfn);
+ num = pfn_to_section_nr(pgdat->node_spanned_pages);
+
+ for (i = section_nr; i < num; i++) {
+ if (present_section_nr(i)) {
+ printk(KERN_INFO "section %ld is busy\n", i);
+ ret = 1;
+ }
+ }
+ return ret;
+}
+
+void free_pgdat(int offline_nid, struct pglist_data *pgdat)
+{
+ struct page *page = virt_to_page(pgdat);
+
+ arch_refresh_nodedata(offline_nid, NULL);
+
+ if (PageSlab(page)) {
+ /* This pgdat is allocated on other node via hot-add */
+ arch_free_nodedata(pgdat);
+ return;
+ }
+
+ if (offline_nid != page_to_nid(page)) {
+ /* This pgdat is allocated on other node as memoryless node */
+ put_page_bootmem(page);
+ return;
+ }
+
+ /*
+ * Ok. This pgdat is same node of offlining node.
+ * Don't free it. Because this area will be removed physically at
+ * next step.
+ */
+
+}
+
+int remove_pgdat(int nid)
+{
+ struct pglist_data *pgdat = NODE_DATA(nid);
+
+ if (cpus_busy_on_node(nid))
+ return -EBUSY;
+
+ if (sections_busy_on_node(pgdat))
+ return -EBUSY;
+
+ node_set_offline(nid);
+ synchronize_sched();
+ synchronize_srcu(&pgdat_remove_srcu);
+
+ free_pgdat(nid, pgdat);
+
+ return 0;
+}
+
#ifdef CONFIG_SPARSEMEM_VMEMMAP
static int __remove_section(struct zone *zone, struct mem_section *ms)
{
@@ -473,7 +549,6 @@ static void rollback_node_hotadd(int nid
return;
}
-
int add_memory(int nid, u64 start, u64 size)
{
pg_data_t *pgdat = NULL;
@@ -842,6 +917,14 @@ repeat:
vm_total_pages = nr_free_pagecache_pages();
writeback_set_ratelimit();
+ if (zone->present_pages == 0)
+ build_all_zonelists();
+
+ if (zone->zone_pgdat->node_present_pages == 0) {
+ node_clear_state(node, N_HIGH_MEMORY);
+ kswapd_stop(node);
+ }
+
memory_notify(MEM_OFFLINE, &arg);
return 0;
--
Yasunori Goto
--
