On 10/04/2011 04:48 PM, Eric Dumazet wrote:
Le mardi 04 octobre 2011 à 16:17 +0400, Glauber Costa a écrit :
This patch uses the "tcp_max_mem" field of the kmem_cgroup to
effectively control the amount of kernel memory pinned by a cgroup.
We have to make sure that none of the memory pressure thresholds
specified in the namespace are bigger than the current cgroup.
Signed-off-by: Glauber Costa<glommer@xxxxxxxxxxxxx>
CC: David S. Miller<davem@xxxxxxxxxxxxx>
CC: Hiroyouki Kamezawa<kamezawa.hiroyu@xxxxxxxxxxxxxx>
CC: Eric W. Biederman<ebiederm@xxxxxxxxxxxx>
---
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -256,6 +256,7 @@ extern int sysctl_tcp_thin_dupack;
struct mem_cgroup;
struct tcp_memcontrol {
/* per-cgroup tcp memory pressure knobs */
+ int tcp_max_memory;
atomic_long_t tcp_memory_allocated;
struct percpu_counter tcp_sockets_allocated;
/* those two are read-mostly, leave them at the end */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
So tcp_max_memory is an "int".
+static u64 tcp_read_limit(struct cgroup *cgrp, struct cftype *cft)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+ return memcg->tcp.tcp_max_memory<< PAGE_SHIFT;
+}
1) Typical integer overflow here.
You need :
return ((u64)memcg->tcp.tcp_max_memory)<< PAGE_SHIFT;
Thanks for spotting this, Eric.
2) Could you add const qualifiers when possible to your pointers ?
Well, I'll go over the patches again and see where I can add them.
Any specific place site you're concerned about?
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