[v5,10/10] Disable task moving when using kernel memory accounting

Submitted by Glauber Costa on Nov. 7, 2011, 3:26 p.m.

Details

Message ID 1320679595-21074-11-git-send-email-glommer@parallels.com
State RFC
Delegated to: David Miller
Headers show

Commit Message

Glauber Costa Nov. 7, 2011, 3:26 p.m.
Since this code is still experimental, we are leaving the exact
details of how to move tasks between cgroups when kernel memory
accounting is used as future work.

For now, we simply disallow movement if there are any pending
accounted memory.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
---
 mm/memcontrol.c |   23 ++++++++++++++++++++++-
 1 files changed, 22 insertions(+), 1 deletions(-)

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diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b532f91..248f92d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5690,10 +5690,19 @@  static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
 {
 	int ret = 0;
 	struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
+	struct mem_cgroup *from = mem_cgroup_from_task(p);
+
+#if defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) && defined(CONFIG_INET)
+	if (from != mem && !mem_cgroup_is_root(from) &&
+	    res_counter_read_u64(&from->tcp.tcp_memory_allocated, RES_USAGE)) {
+		printk(KERN_WARNING "Can't move tasks between cgroups: "
+			"Kernel memory held. task: %s\n", p->comm);
+		return 1;
+	}
+#endif
 
 	if (mem->move_charge_at_immigrate) {
 		struct mm_struct *mm;
-		struct mem_cgroup *from = mem_cgroup_from_task(p);
 
 		VM_BUG_ON(from == mem);
 
@@ -5861,6 +5870,18 @@  static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
 				struct cgroup *cgroup,
 				struct task_struct *p)
 {
+	struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
+	struct mem_cgroup *from = mem_cgroup_from_task(p);
+
+#if defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) && defined(CONFIG_INET)
+	if (from != mem && !mem_cgroup_is_root(from) &&
+	    res_counter_read_u64(&from->tcp.tcp_memory_allocated, RES_USAGE)) {
+		printk(KERN_WARNING "Can't move tasks between cgroups: "
+			"Kernel memory held. task: %s\n", p->comm);
+		return 1;
+	}
+#endif
+
 	return 0;
 }
 static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,