On 11/28/2011 02:32 AM, KAMEZAWA Hiroyuki wrote:
On Fri, 25 Nov 2011 15:38:16 -0200
Glauber Costa<glommer@xxxxxxxxxxxxx> wrote:
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@xxxxxxxxxxxxx>
CC: Hiroyouki Kamezawa<kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
mm/memcontrol.c | 23 ++++++++++++++++++++++-
1 files changed, 22 insertions(+), 1 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2df5d3c..ab7e57b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5451,10 +5451,19 @@ 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_mem.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
Hmm, the kernel memory is not guaranteed as being held by the 'task' ?
How about
"Now, moving task between cgroup is disallowed while the source cgroup
containes kmem reference." ?
Hmm.. we need to fix this task-move/rmdir issue before production use.
Thanks,
-Kame
Hi Kame,
Let me tell you the direction I am going wrt task movement: The only
reasons I haven't included so far, is that I believe it needs more
testing, and as you know, I am right now more interested in getting past
the initial barriers for inclusion. I am committed to fix anything that
needs to be fixed - stylish or non-stylish before we remove the
experimental flag.
So what I intend to do, is to basically
* lock the task,
* scan through its file descriptors list,
* identify which of them are sockets,
* cast them to struct sock *,
* see if it has a cgrp associated
* see if cgrp == from
At this point we can decrement sockets allocated by 1 in from, and
memory_allocated by sk_forward_alloc (increasing by equal quantities in
the destination cgroup)
I belive it will work.
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