[PATCH: 011/017]Memory hotplug for new nodes v.4.(start kswapd)

From: Yasunori Goto
Date: Fri Mar 17 2006 - 03:21:49 EST


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


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

include/linux/swap.h | 5 +++++
mm/vmscan.c | 35 ++++++++++++++++++++++++++---------
2 files changed, 31 insertions(+), 9 deletions(-)

Index: pgdat8/mm/vmscan.c
===================================================================
--- pgdat8.orig/mm/vmscan.c 2006-03-16 16:05:38.000000000 +0900
+++ pgdat8/mm/vmscan.c 2006-03-16 16:06:27.000000000 +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>
@@ -1843,20 +1844,36 @@ 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: pgdat8/include/linux/swap.h
===================================================================
--- pgdat8.orig/include/linux/swap.h 2006-03-16 16:05:38.000000000 +0900
+++ pgdat8/include/linux/swap.h 2006-03-16 16:06:27.000000000 +0900
@@ -208,6 +208,11 @@ static inline int migrate_pages(struct l
#define fail_migrate_page NULL
#endif

+#ifdef CONFIG_MEMORY_HOTPLUG
+/* start new kswapd for new node */
+extern int kswapd_run(int nid);
+#endif
+
#ifdef CONFIG_MMU
/* linux/mm/shmem.c */
extern int shmem_unuse(swp_entry_t entry, struct page *page);

--
Yasunori Goto


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