On Mon, Sep 19, 2011 at 6:26 AM, Glauber Costa <glommer@xxxxxxxxxxxxx> wrote:
> 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>
> ---
> Documentation/cgroups/memory.txt | 1 +
> include/linux/memcontrol.h | 10 ++++
> mm/memcontrol.c | 89 +++++++++++++++++++++++++++++++++++---
> net/ipv4/sysctl_net_ipv4.c | 20 ++++++++
> 4 files changed, 113 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
> index 6f1954a..1ffde3e 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.max_memory # set/show hard limit for tcp buf memory
>
> 1. History
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 6b8c0c0..2df6db8 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -416,6 +416,9 @@ int tcp_init_cgroup_fill(struct proto *prot, struct cgroup *cgrp,
> struct cgroup_subsys *ss);
> void tcp_destroy_cgroup(struct proto *prot, struct cgroup *cgrp,
> struct cgroup_subsys *ss);
> +
> +unsigned long tcp_max_memory(struct mem_cgroup *cg);
> +void tcp_prot_mem(struct mem_cgroup *cg, long val, int idx);
> #else
> /* memcontrol includes sockets.h, that includes memcontrol.h ... */
> static inline void memcg_sock_mem_alloc(struct mem_cgroup *mem,
> @@ -441,6 +444,13 @@ static inline void sock_update_memcg(struct sock *sk)
> static inline void sock_release_memcg(struct sock *sk)
> {
> }
> +static inline unsigned long tcp_max_memory(struct mem_cgroup *cg)
> +{
> + return 0;
> +}
> +static inline void tcp_prot_mem(struct mem_cgroup *cg, 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 5e9b2c7..be5ab89 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -345,6 +345,7 @@ struct mem_cgroup {
> spinlock_t pcp_counter_lock;
>
> /* per-cgroup tcp memory pressure knobs */
> + int tcp_max_memory;
Aren't we better of abstracting this in a different structure?
Including all the tcp parameters in that abstraction and adding that
structure here?
> atomic_long_t tcp_memory_allocated;
> struct percpu_counter tcp_sockets_allocated;
> /* those two are read-mostly, leave them at the end */
> @@ -352,6 +353,11 @@ struct mem_cgroup {
> int tcp_memory_pressure;
> };
>
> +static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
> +{
> + return (mem == root_mem_cgroup);
> +}
> +
> static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
> /* Writing them here to avoid exposing memcg's inner layout */
> #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
> @@ -466,6 +472,56 @@ struct percpu_counter *sockets_allocated_tcp(struct mem_cgroup *sg)
> return &sg->tcp_sockets_allocated;
> }
>
> +static int tcp_write_maxmem(struct cgroup *cgrp, struct cftype *cft, u64 val)
> +{
> + struct mem_cgroup *sg = mem_cgroup_from_cont(cgrp);
sg, I'd prefer memcg, does sg stand for socket group?
> + struct mem_cgroup *parent = parent_mem_cgroup(sg);
> + struct net *net = current->nsproxy->net_ns;
> + int i;
> +
> + if (!cgroup_lock_live_group(cgrp))
> + return -ENODEV;
> +
> + /*
> + * We can't allow more memory than our parents. Since this
> + * will be tested for all calls, by induction, there is no need
> + * to test any parent other than our own
> + * */
> + if (parent && (val > parent->tcp_max_memory))
> + val = parent->tcp_max_memory;
> +
> + sg->tcp_max_memory = val;
> +
> + for (i = 0; i < 3; i++)
> + sg->tcp_prot_mem[i] = min_t(long, val,
> + net->ipv4.sysctl_tcp_mem[i]);
> +
> + cgroup_unlock();
> +
> + return 0;
> +}
> +
> +static u64 tcp_read_maxmem(struct cgroup *cgrp, struct cftype *cft)
> +{
> + struct mem_cgroup *sg = mem_cgroup_from_cont(cgrp);
sg? We generally use memcg as a convention
> + u64 ret;
> +
> + if (!cgroup_lock_live_group(cgrp))
> + return -ENODEV;
> + ret = sg->tcp_max_memory;
> +
> + cgroup_unlock();
> + return ret;
> +}
> +
> +static struct cftype tcp_files[] = {
> + {
> + .name = "kmem.tcp.max_memory",
> + .write_u64 = tcp_write_maxmem,
> + .read_u64 = tcp_read_maxmem,
> + },
> +};
> +
> /*
> * For ipv6, we only need to fill in the function pointers (can't initialize
> * things twice). So keep it separated
> @@ -487,8 +543,10 @@ int tcp_init_cgroup(struct proto *prot, struct cgroup *cgrp,
> struct cgroup_subsys *ss)
> {
> struct mem_cgroup *cg = mem_cgroup_from_cont(cgrp);
> + struct mem_cgroup *parent = parent_mem_cgroup(cg);
> unsigned long limit;
> struct net *net = current->nsproxy->net_ns;
> + int ret = 0;
>
> cg->tcp_memory_pressure = 0;
> atomic_long_set(&cg->tcp_memory_allocated, 0);
> @@ -497,12 +555,25 @@ int tcp_init_cgroup(struct proto *prot, struct cgroup *cgrp,
> limit = nr_free_buffer_pages() / 8;
> limit = max(limit, 128UL);
>
> + if (parent)
> + cg->tcp_max_memory = parent->tcp_max_memory;
> + else
> + cg->tcp_max_memory = limit * 2;
> +
> cg->tcp_prot_mem[0] = net->ipv4.sysctl_tcp_mem[0];
> cg->tcp_prot_mem[1] = net->ipv4.sysctl_tcp_mem[1];
> cg->tcp_prot_mem[2] = net->ipv4.sysctl_tcp_mem[2];
>
> tcp_init_cgroup_fill(prot, cgrp, ss);
> - return 0;
> + /*
> + * For non-root cgroup, we need to set up all tcp-related variables,
> + * but to be consistent with the rest of kmem management, we don't
> + * expose any of the controls
> + */
> + if (!mem_cgroup_is_root(cg))
> + ret = cgroup_add_files(cgrp, ss, tcp_files,
> + ARRAY_SIZE(tcp_files));
> + return ret;
> }
> EXPORT_SYMBOL(tcp_init_cgroup);
>
> @@ -514,6 +585,16 @@ void tcp_destroy_cgroup(struct proto *prot, struct cgroup *cgrp,
> percpu_counter_destroy(&cg->tcp_sockets_allocated);
> }
> EXPORT_SYMBOL(tcp_destroy_cgroup);
> +
> +unsigned long tcp_max_memory(struct mem_cgroup *cg)
> +{
> + return cg->tcp_max_memory;
> +}
> +
> +void tcp_prot_mem(struct mem_cgroup *cg, long val, int idx)
> +{
> + cg->tcp_prot_mem[idx] = val;
> +}
> #endif /* CONFIG_INET */
> #endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
>
> @@ -1092,12 +1173,6 @@ static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
> #define for_each_mem_cgroup_all(iter) \
> for_each_mem_cgroup_tree_cond(iter, NULL, true)
>
> -
> -static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
> -{
> - return (mem == root_mem_cgroup);
> -}
> -
> void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
> {
> struct mem_cgroup *mem;
> diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
> index bbd67ab..cdc35f6 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 +183,10 @@ 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
> + int i;
> + struct mem_cgroup *cg;
> +#endif
>
> ctl_table tmp = {
> .data = &vec,
> @@ -198,6 +203,21 @@ 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);
> + for (i = 0; i < 3; i++)
> + if (vec[i] > tcp_max_memory(cg)) {
> + rcu_read_unlock();
> + return -EINVAL;
> + }
> +
> + 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];
Balbir Singh
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