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Commit f0cb3c76 authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Linus Torvalds
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mm: drain percpu lru add/rotate page-vectors on cpu hot-unplug 



This cpu hotplug hook was accidentally removed in commit 00a62ce9
("mm: fix Committed_AS underflow on large NR_CPUS environment")

The visible effect of this accident: some pages are borrowed in per-cpu
page-vectors.  Truncate can deal with it, but these pages cannot be
reused while this cpu is offline.  So this is like a temporary memory
leak.

Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Eric B Munson <ebmunson@us.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3268c63e

include/linux/swap.h

+1 −0
Original line number Diff line number Diff line
@@ -223,6 +223,7 @@ extern void lru_add_page_tail(struct zone* zone, 
extern void activate_page(struct page *);

extern void mark_page_accessed(struct page *);

extern void lru_add_drain(void);

extern void lru_add_drain_cpu(int cpu);

extern int lru_add_drain_all(void);

extern void rotate_reclaimable_page(struct page *page);

extern void deactivate_page(struct page *page);

mm/page_alloc.c

+1 −0
Original line number Diff line number Diff line
@@ -4825,6 +4825,7 @@ static int page_alloc_cpu_notify(struct notifier_block *self, 
	int cpu = (unsigned long)hcpu;



	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {

		lru_add_drain_cpu(cpu);

		drain_pages(cpu);



		/*

mm/swap.c

+2 −2
Original line number Diff line number Diff line
@@ -496,7 +496,7 @@ static void lru_deactivate_fn(struct page *page, void *arg) 
 * Either "cpu" is the current CPU, and preemption has already been

 * disabled; or "cpu" is being hot-unplugged, and is already dead.

 */

static void drain_cpu_pagevecs(int cpu)

void lru_add_drain_cpu(int cpu)

{

	struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu);

	struct pagevec *pvec;
@@ -553,7 +553,7 @@ void deactivate_page(struct page *page) 


void lru_add_drain(void)

{

	drain_cpu_pagevecs(get_cpu());

	lru_add_drain_cpu(get_cpu());

	put_cpu();

}