[Patch: 005/006] pgdat allocation for new node add (export kswapd start func)

Yasunori Goto
2006-04-20T10:12:24Z

When node is hot-added, kswapd for the node should start.
This export kswapd start function as kswapd_run() to use at add_memory().

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

include/linux/swap.h | 2 ++
mm/vmscan.c | 35 ++++++++++++++++++++++++++---------
2 files changed, 28 insertions(+), 9 deletions(-)

Index: pgdat11/mm/vmscan.c
===================================================================
--- pgdat11.orig/mm/vmscan.c 2006-04-20 11:00:07.000000000 +0900
+++ pgdat11/mm/vmscan.c 2006-04-20 11:00:33.000000000 +0900
@@ -35,6 +35,7 @@
#include <linux/notifier.h>
#include <linux/rwsem.h>
#include <linux/delay.h>
+#include <linux/kthread.h>

#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -1353,20 +1354,36 @@ static int __devinit cpu_callback(struct
}
#endif /* CONFIG_HOTPLUG_CPU */

+/*
+ * This kswapd start function will be called by init and node-hot-add.
+ * On node-hot-add, kswapd will moved to proper cpus if cpus are hot-added.
+ */
+int kswapd_run(int nid)
+{
+ pg_data_t *pgdat = NODE_DATA(nid);
+ int ret = 0;
+
+ if (pgdat->kswapd)
+ return 0;
+
+ pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid);
+ if (pgdat->kswapd == ERR_PTR(-ENOMEM)) {
+ /* failure at boot is fatal */
+ BUG_ON(system_state == SYSTEM_BOOTING);
+ printk("faled to run kswapd on node %d\n",nid);
+ ret = -1;
+ }
+ return ret;
+}
+
static int __init kswapd_init(void)
{
- pg_data_t *pgdat;
+ int nid;

swap_setup();
- for_each_online_pgdat(pgdat) {
- pid_t pid;
+ for_each_online_node(nid)
+ kswapd_run(nid);

- pid = kernel_thread(kswapd, pgdat, CLONE_KERNEL);
- BUG_ON(pid < 0);
- read_lock(&tasklist_lock);
- pgdat->kswapd = find_task_by_pid(pid);
- read_unlock(&tasklist_lock);
- }
total_memory = nr_free_pagecache_pages();
hotcpu_notifier(cpu_callback, 0);
return 0;
Index: pgdat11/include/linux/swap.h
===================================================================
--- pgdat11.orig/include/linux/swap.h 2006-04-20 11:00:07.000000000 +0900
+++ pgdat11/include/linux/swap.h 2006-04-20 11:00:33.000000000 +0900
@@ -212,6 +212,8 @@ static inline int zone_reclaim(struct zo
}
#endif

+extern int kswapd_run(int nid);
+
#ifdef CONFIG_MMU
/* linux/mm/shmem.c */
extern int shmem_unuse(swp_entry_t entry, struct page *page);