This patch uses the "tcp.limit_in_bytes" field of the kmem_cgroup to
effectively control the amount of kernel memory pinned by a cgroup.
This value is ignored in the root cgroup, and in all others,
caps the value specified by the admin in the net namespaces'
view of tcp_sysctl_mem.
If namespaces are being used, the admin is allowed to set a
value bigger than cgroup's maximum, the same way it is allowed
to set pretty much unlimited values in a real box.
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>
---
Documentation/cgroups/memory.txt | 1 +
include/linux/memcontrol.h | 9 ++++
mm/memcontrol.c | 76 +++++++++++++++++++++++++++++++++++++-
net/ipv4/sysctl_net_ipv4.c | 14 +++++++
4 files changed, 99 insertions(+), 1 deletions(-)
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index bf00cd2..c1db134 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -78,6 +78,7 @@ Brief summary of control files.
memory.independent_kmem_limit # select whether or not kernel memory limits are
independent of user limits
+ memory.kmem.tcp.limit_in_bytes # set/show hard limit for tcp buf memory
1. History
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 994a06a..d025979 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -402,10 +402,19 @@ void memcg_memory_allocated_sub(struct mem_cgroup *memcg, struct cg_proto *prot,
unsigned long amt);
u64 memcg_memory_allocated_read(struct mem_cgroup *memcg,
struct cg_proto *prot);
+unsigned long long tcp_max_memory(const struct mem_cgroup *memcg);
+void tcp_prot_mem(struct mem_cgroup *memcg, long val, int idx);
#else
static inline void sock_update_memcg(struct sock *sk)
{
}
+static inline unsigned long long tcp_max_memory(const struct mem_cgroup *memcg)
+{
+ return 0;
+}
+static inline void tcp_prot_mem(struct mem_cgroup *memcg, long val, int idx)
+{
+}
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
#endif /* CONFIG_INET */
#endif /* _LINUX_MEMCONTROL_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 63360f8..ee122a6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -365,6 +365,7 @@ enum mem_type {
_MEMSWAP,
_OOM_TYPE,
_KMEM,
+ _KMEM_TCP,
};
#define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
@@ -500,6 +501,35 @@ struct percpu_counter *sockets_allocated_tcp(struct mem_cgroup *memcg)
}
EXPORT_SYMBOL(sockets_allocated_tcp);
+static void tcp_update_limit(struct mem_cgroup *memcg, u64 val)
+{
+ struct net *net = current->nsproxy->net_ns;
+ int i;
+
+ val >>= PAGE_SHIFT;
+
+ for (i = 0; i < 3; i++)
+ memcg->tcp.tcp_prot_mem[i] = min_t(long, val,
+ net->ipv4.sysctl_tcp_mem[i]);
+}
+
+static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
+ const char *buffer);
+
+static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft);
+/*
+ * We need those things internally in pages, so don't reuse
+ * mem_cgroup_{read,write}
+ */
+static struct cftype tcp_files[] = {
+ {
+ .name = "kmem.tcp.limit_in_bytes",
+ .write_string = mem_cgroup_write,
+ .read_u64 = mem_cgroup_read,
+ .private = MEMFILE_PRIVATE(_KMEM_TCP, RES_LIMIT),
+ },
+};
+
static void tcp_create_cgroup(struct mem_cgroup *cg, struct cgroup_subsys *ss)
{
/*
@@ -527,6 +557,7 @@ static void tcp_create_cgroup(struct mem_cgroup *cg, struct cgroup_subsys *ss)
int tcp_init_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
{
struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+ struct mem_cgroup *parent = parent_mem_cgroup(memcg);
struct net *net = current->nsproxy->net_ns;
/*
* We need to initialize it at populate, not create time.
@@ -537,7 +568,20 @@ int tcp_init_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
memcg->tcp.tcp_prot_mem[1] = net->ipv4.sysctl_tcp_mem[1];
memcg->tcp.tcp_prot_mem[2] = net->ipv4.sysctl_tcp_mem[2];
- return 0;
+ /* Let root cgroup unlimited. All others, respect parent's if needed */
+ if (parent && !parent->use_hierarchy) {
+ unsigned long limit;
+ int ret;
+ limit = nr_free_buffer_pages() / 8;
+ limit = max(limit, 128UL);
+ ret = res_counter_set_limit(&memcg->tcp.tcp_memory_allocated,
+ limit * 2);
+ if (ret)
+ return ret;
+ }
+
+ return cgroup_add_files(cgrp, ss, tcp_files,
+ ARRAY_SIZE(tcp_files));
}
EXPORT_SYMBOL(tcp_init_cgroup);
@@ -548,6 +592,18 @@ void tcp_destroy_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
percpu_counter_destroy(&memcg->tcp.tcp_sockets_allocated);
}
EXPORT_SYMBOL(tcp_destroy_cgroup);
+
+unsigned long long tcp_max_memory(const struct mem_cgroup *memcg)
+{
+ struct mem_cgroup *cmemcg = (struct mem_cgroup *)memcg;
+ return res_counter_read_u64(&cmemcg->tcp.tcp_memory_allocated,
+ RES_LIMIT);
+}
+
+void tcp_prot_mem(struct mem_cgroup *memcg, long val, int idx)
+{
+ memcg->tcp.tcp_prot_mem[idx] = val;
+}
#endif /* CONFIG_INET */
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
@@ -4067,6 +4123,15 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
val = res_counter_read_u64(&mem->kmem, name);
break;
+#if defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) && defined(CONFIG_INET)
+ case _KMEM_TCP:
+ /* Be explicit: tcp root does not have a res_counter */
+ if (mem_cgroup_is_root(mem))
+ val = RESOURCE_MAX;
+ else
+ val = res_counter_read_u64(&mem->tcp.tcp_memory_allocated, name);
+ break;
+#endif
default:
BUG();
break;
@@ -4099,6 +4164,15 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
break;
if (type == _MEM)
ret = mem_cgroup_resize_limit(memcg, val);
+
+#if defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) && defined(CONFIG_INET)
+ else if (type == _KMEM_TCP) {
+ ret = res_counter_set_limit(&memcg->tcp.tcp_memory_allocated,
+ val);
+ if (!ret)
+ tcp_update_limit(memcg, val);
+ }
+#endif
else
ret = mem_cgroup_resize_memsw_limit(memcg, val);
break;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index bbd67ab..915e192 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -14,6 +14,7 @@
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/nsproxy.h>
+#include <linux/memcontrol.h>
#include <linux/swap.h>
#include <net/snmp.h>
#include <net/icmp.h>
@@ -182,6 +183,9 @@ static int ipv4_tcp_mem(ctl_table *ctl, int write,
int ret;
unsigned long vec[3];
struct net *net = current->nsproxy->net_ns;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ struct mem_cgroup *cg;
+#endif
ctl_table tmp = {
.data = &vec,
@@ -198,6 +202,16 @@ static int ipv4_tcp_mem(ctl_table *ctl, int write,
if (ret)
return ret;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ rcu_read_lock();
+ cg = mem_cgroup_from_task(current);
+
+ tcp_prot_mem(cg, vec[0], 0);
+ tcp_prot_mem(cg, vec[1], 1);
+ tcp_prot_mem(cg, vec[2], 2);
+ rcu_read_unlock();
+#endif
+
net->ipv4.sysctl_tcp_mem[0] = vec[0];
net->ipv4.sysctl_tcp_mem[1] = vec[1];
net->ipv4.sysctl_tcp_mem[2] = vec[2];
--
1.7.6.4
--
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