Commit 8fe23e05 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds

mm: clear node in N_HIGH_MEMORY and stop kswapd when all memory is offlined

When memory is hot-removed, its node must be cleared in N_HIGH_MEMORY if
there are no present pages left.

In such a situation, kswapd must also be stopped since it has nothing left
to do.
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9b5e5d0f
......@@ -273,6 +273,7 @@ extern int scan_unevictable_register_node(struct node *node);
extern void scan_unevictable_unregister_node(struct node *node);
extern int kswapd_run(int nid);
extern void kswapd_stop(int nid);
#ifdef CONFIG_MMU
/* linux/mm/shmem.c */
......
......@@ -853,6 +853,10 @@ int offline_pages(unsigned long start_pfn,
setup_per_zone_wmarks();
calculate_zone_inactive_ratio(zone);
if (!node_present_pages(node)) {
node_clear_state(node, N_HIGH_MEMORY);
kswapd_stop(node);
}
vm_total_pages = nr_free_pagecache_pages();
writeback_set_ratelimit();
......
......@@ -2173,6 +2173,7 @@ static int kswapd(void *p)
order = 0;
for ( ; ; ) {
unsigned long new_order;
int ret;
prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
new_order = pgdat->kswapd_max_order;
......@@ -2184,19 +2185,23 @@ static int kswapd(void *p)
*/
order = new_order;
} else {
if (!freezing(current))
if (!freezing(current) && !kthread_should_stop())
schedule();
order = pgdat->kswapd_max_order;
}
finish_wait(&pgdat->kswapd_wait, &wait);
if (!try_to_freeze()) {
/* We can speed up thawing tasks if we don't call
* balance_pgdat after returning from the refrigerator
*/
ret = try_to_freeze();
if (kthread_should_stop())
break;
/*
* We can speed up thawing tasks if we don't call balance_pgdat
* after returning from the refrigerator
*/
if (!ret)
balance_pgdat(pgdat, order);
}
}
return 0;
}
......@@ -2451,6 +2456,17 @@ int kswapd_run(int nid)
return ret;
}
/*
* Called by memory hotplug when all memory in a node is offlined.
*/
void kswapd_stop(int nid)
{
struct task_struct *kswapd = NODE_DATA(nid)->kswapd;
if (kswapd)
kthread_stop(kswapd);
}
static int __init kswapd_init(void)
{
int nid;
......
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