Commit ff7283fa authored Feb 07, 2008 by KAMEZAWA Hiroyuki Committed by Linus Torvalds Feb 07, 2008

bugfix for memory cgroup controller: avoid !PageLRU page in mem_cgroup_isolate_pages



This patch makes mem_cgroup_isolate_pages() to be

  - ignore !PageLRU pages.
  - fixes the bug that isolation makes no progress if page_zone(page) != zone
    page once find. (just increment scan in this case.)

kswapd and memory migration removes a page from list when it handles
a page for reclaiming/migration.

Because __isolate_lru_page() doesn't moves page !PageLRU pages, it will
be safe to avoid touching !PageLRU() page and its page_cgroup.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Paul Menage <menage@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: David Rientjes <rientjes@google.com>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent ae41be37

mm/memcontrol.c

+10 −3

Original line number	Diff line number	Diff line
		@@ -250,7 +250,7 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
		unsigned long scan;
		LIST_HEAD(pc_list);
		struct list_head *src;
		struct page_cgroup *pc;
		struct page_cgroup pc, tmp;

		if (active)
		src = &mem_cont->active_list;
		@@ -258,11 +258,18 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
		src = &mem_cont->inactive_list;

		spin_lock(&mem_cont->lru_lock);
		for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) {
		pc = list_entry(src->prev, struct page_cgroup, lru);
		scan = 0;
		list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
		if (scan++ > nr_to_scan)
		break;
		page = pc->page;
		VM_BUG_ON(!pc);

		if (unlikely(!PageLRU(page))) {
		scan--;
		continue;
		}

		if (PageActive(page) && !active) {
		__mem_cgroup_move_lists(pc, true);
		scan--;

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