[PATCH v2 4/7] per-cgroup tcp buffers control

Glauber Costa
2011-09-15T01:48:05Z

With all the infrastructure in place, this patch implements
per-cgroup control for tcp memory pressure handling.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: David S. Miller <davem@davemloft.net>
CC: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: Eric W. Biederman <ebiederm@xmission.com>
---
include/linux/memcontrol.h | 8 +++
include/net/sock.h | 14 +++++-
include/net/tcp.h | 10 ++--
mm/memcontrol.c | 115 +++++++++++++++++++++++++++++++++++++++++++-
net/core/sock.c | 28 ++++++++++-
net/ipv4/tcp.c | 44 ++++++++---------
net/ipv4/tcp_ipv4.c | 14 ++++--
net/ipv6/tcp_ipv6.c | 14 ++++--
8 files changed, 203 insertions(+), 44 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 15c337f..47e05ba 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -404,6 +404,14 @@ void memcg_sock_mem_alloc(struct mem_cgroup *mem, struct proto *prot,
void memcg_sock_mem_free(struct mem_cgroup *mem, struct proto *prot, int amt);
void memcg_sockets_allocated_dec(struct mem_cgroup *mem, struct proto *prot);
void memcg_sockets_allocated_inc(struct mem_cgroup *mem, struct proto *prot);
+int tcp_init_cgroup(struct proto *prot, struct cgroup *cgrp,
+ struct cgroup_subsys *ss);
+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);
+void tcp_destroy_cgroup_fill(struct proto *prot, struct cgroup *cgrp,
+ struct cgroup_subsys *ss);
#include <net/sock.h>

static inline void sock_update_memcg(struct sock *sk)
diff --git a/include/net/sock.h b/include/net/sock.h
index 78832f9..ec3c7fa 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -64,6 +64,7 @@
#include <net/dst.h>
#include <net/checksum.h>

+int sockets_populate(struct cgroup *cgrp, struct cgroup_subsys *ss);
/*
* This structure really needs to be cleaned up.
* Most of it is for TCP, and not used by any of
@@ -814,7 +815,18 @@ struct proto {
int *(*memory_pressure)(struct mem_cgroup *sg);
/* Pointer to the per-cgroup version of the the sysctl_mem field */
long *(*prot_mem)(struct mem_cgroup *sg);
-
+ /*
+ * cgroup specific init/deinit functions. Called once for all
+ * protocols that implement it, from cgroups populate function.
+ * This function has to setup any files the protocol want to
+ * appear in the kmem cgroup filesystem.
+ */
+ int (*init_cgroup)(struct proto *prot,
+ struct cgroup *cgrp,
+ struct cgroup_subsys *ss);
+ void (*destroy_cgroup)(struct proto *prot,
+ struct cgroup *cgrp,
+ struct cgroup_subsys *ss);
int *sysctl_wmem;
int *sysctl_rmem;
int max_header;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index c835ae3..ce3c211 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -255,10 +255,10 @@ extern int sysctl_tcp_thin_linear_timeouts;
extern int sysctl_tcp_thin_dupack;

struct mem_cgroup;
-extern long *tcp_sysctl_mem(struct mem_cgroup *sg);
-struct percpu_counter *sockets_allocated_tcp(struct mem_cgroup *sg);
-int *memory_pressure_tcp(struct mem_cgroup *sg);
-atomic_long_t *memory_allocated_tcp(struct mem_cgroup *sg);
+extern long *tcp_sysctl_mem_nocg(struct mem_cgroup *sg);
+struct percpu_counter *sockets_allocated_tcp_nocg(struct mem_cgroup *sg);
+int *memory_pressure_tcp_nocg(struct mem_cgroup *sg);
+atomic_long_t *memory_allocated_tcp_nocg(struct mem_cgroup *sg);

/*
* The next routines deal with comparing 32 bit unsigned ints
@@ -1002,7 +1002,7 @@ static inline void tcp_openreq_init(struct request_sock *req,
ireq->loc_port = tcp_hdr(skb)->dest;
}

-extern void tcp_enter_memory_pressure(struct sock *sk);
+extern void tcp_enter_memory_pressure_nocg(struct sock *sk);

static inline int keepalive_intvl_when(const struct tcp_sock *tp)
{
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 289fc2c..7db430c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -343,13 +343,21 @@ struct mem_cgroup {
*/
struct mem_cgroup_stat_cpu nocpu_base;
spinlock_t pcp_counter_lock;
+
+ /* per-cgroup tcp memory pressure knobs */
+ atomic_long_t tcp_memory_allocated;
+ struct percpu_counter tcp_sockets_allocated;
+ /* those two are read-mostly, leave them at the end */
+ long tcp_prot_mem[3];
+ int tcp_memory_pressure;
};

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
#ifdef CONFIG_INET
-
+#include <net/tcp.h>
+#include <net/ip.h>
void memcg_sock_mem_alloc(struct mem_cgroup *mem, struct proto *prot,
int amt, int *parent_failure)
{
@@ -392,6 +400,102 @@ void memcg_sockets_allocated_inc(struct mem_cgroup *mem, struct proto *prot)
percpu_counter_inc(prot->sockets_allocated(mem));
}
EXPORT_SYMBOL(memcg_sockets_allocated_inc);
+
+static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont);
+/*
+ * Pressure flag: try to collapse.
+ * Technical note: it is used by multiple contexts non atomically.
+ * All the __sk_mem_schedule() is of this nature: accounting
+ * is strict, actions are advisory and have some latency.
+ */
+void tcp_enter_memory_pressure(struct sock *sk)
+{
+ struct mem_cgroup *sg = sk->sk_cgrp;
+ if (!sg->tcp_memory_pressure) {
+ NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
+ sg->tcp_memory_pressure = 1;
+ }
+}
+
+long *tcp_sysctl_mem(struct mem_cgroup *cg)
+{
+ return cg->tcp_prot_mem;
+}
+
+atomic_long_t *memory_allocated_tcp(struct mem_cgroup *cg)
+{
+ return &(cg->tcp_memory_allocated);
+}
+
+int *memory_pressure_tcp(struct mem_cgroup *sg)
+{
+ return &sg->tcp_memory_pressure;
+}
+
+struct percpu_counter *sockets_allocated_tcp(struct mem_cgroup *sg)
+{
+ return &sg->tcp_sockets_allocated;
+}
+
+/*
+ * For ipv6, we only need to fill in the function pointers (can't initialize
+ * things twice). So keep it separated
+ */
+int tcp_init_cgroup_fill(struct proto *prot, struct cgroup *cgrp,
+ struct cgroup_subsys *ss)
+{
+ prot->enter_memory_pressure = tcp_enter_memory_pressure;
+ prot->memory_allocated = memory_allocated_tcp;
+ prot->prot_mem = tcp_sysctl_mem;
+ prot->sockets_allocated = sockets_allocated_tcp;
+ prot->memory_pressure = memory_pressure_tcp;
+
+ return 0;
+}
+EXPORT_SYMBOL(tcp_init_cgroup_fill);
+
+void tcp_destroy_cgroup_fill(struct proto *prot, struct cgroup *cgrp,
+ struct cgroup_subsys *ss)
+{
+ prot->enter_memory_pressure = tcp_enter_memory_pressure_nocg;
+ prot->memory_allocated = memory_allocated_tcp_nocg;
+ prot->prot_mem = tcp_sysctl_mem_nocg;
+ prot->sockets_allocated = sockets_allocated_tcp_nocg;
+ prot->memory_pressure = memory_pressure_tcp_nocg;
+}
+EXPORT_SYMBOL(tcp_destroy_cgroup_fill);
+
+int tcp_init_cgroup(struct proto *prot, struct cgroup *cgrp,
+ struct cgroup_subsys *ss)
+{
+ struct mem_cgroup *cg = mem_cgroup_from_cont(cgrp);
+ unsigned long limit;
+
+ cg->tcp_memory_pressure = 0;
+ atomic_long_set(&cg->tcp_memory_allocated, 0);
+ percpu_counter_init(&cg->tcp_sockets_allocated, 0);
+
+ limit = nr_free_buffer_pages() / 8;
+ limit = max(limit, 128UL);
+
+ cg->tcp_prot_mem[0] = sysctl_tcp_mem[0];
+ cg->tcp_prot_mem[1] = sysctl_tcp_mem[1];
+ cg->tcp_prot_mem[2] = sysctl_tcp_mem[2];
+
+ tcp_init_cgroup_fill(prot, cgrp, ss);
+ return 0;
+}
+EXPORT_SYMBOL(tcp_init_cgroup);
+
+void tcp_destroy_cgroup(struct proto *prot, struct cgroup *cgrp,
+ struct cgroup_subsys *ss)
+{
+ struct mem_cgroup *cg = mem_cgroup_from_cont(cgrp);
+
+ percpu_counter_destroy(&cg->tcp_sockets_allocated);
+ tcp_destroy_cgroup_fill(prot, cgrp, ss);
+}
+EXPORT_SYMBOL(tcp_destroy_cgroup);
#endif /* CONFIG_INET */
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */

@@ -4991,11 +5095,18 @@ static struct cftype kmem_cgroup_files[] = {

static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss)
{
+ int ret;
+
if (!do_kmem_account)
return 0;

- return cgroup_add_files(cont, ss, kmem_cgroup_files,
+ ret = cgroup_add_files(cont, ss, kmem_cgroup_files,
ARRAY_SIZE(kmem_cgroup_files));
+ if (!ret)
+ ret = sockets_populate(cont, ss);
+
+ return ret;
+
};

#else
diff --git a/net/core/sock.c b/net/core/sock.c
index 338d572..78bea26 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -135,6 +135,31 @@
#include <net/tcp.h>
#endif

+static DEFINE_RWLOCK(proto_list_lock);
+static LIST_HEAD(proto_list);
+
+int sockets_populate(struct cgroup *cgrp, struct cgroup_subsys *ss)
+{
+ struct proto *proto;
+ int ret = 0;
+
+ read_lock(&proto_list_lock);
+ list_for_each_entry(proto, &proto_list, node) {
+ if (proto->init_cgroup)
+ ret |= proto->init_cgroup(proto, cgrp, ss);
+ }
+ if (!ret)
+ goto out;
+
+ list_for_each_entry_continue_reverse(proto, &proto_list, node)
+ if (proto->destroy_cgroup)
+ proto->destroy_cgroup(proto, cgrp, ss);
+
+out:
+ read_unlock(&proto_list_lock);
+ return ret;
+}
+
/*
* Each address family might have different locking rules, so we have
* one slock key per address family:
@@ -2260,9 +2285,6 @@ void sk_common_release(struct sock *sk)
}
EXPORT_SYMBOL(sk_common_release);

-static DEFINE_RWLOCK(proto_list_lock);
-static LIST_HEAD(proto_list);
-
#ifdef CONFIG_PROC_FS
#define PROTO_INUSE_NR 64 /* should be enough for the first time */
struct prot_inuse {
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 452245f..156b836 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -290,13 +290,6 @@ EXPORT_SYMBOL(sysctl_tcp_mem);
EXPORT_SYMBOL(sysctl_tcp_rmem);
EXPORT_SYMBOL(sysctl_tcp_wmem);

-atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
-
-/*
- * Current number of TCP sockets.
- */
-struct percpu_counter tcp_sockets_allocated;
-
/*
* TCP splice context
*/
@@ -306,46 +299,49 @@ struct tcp_splice_state {
unsigned int flags;
};

-/*
- * Pressure flag: try to collapse.
- * Technical note: it is used by multiple contexts non atomically.
- * All the __sk_mem_schedule() is of this nature: accounting
- * is strict, actions are advisory and have some latency.
- */
+/* Current number of TCP sockets. */
+struct percpu_counter tcp_sockets_allocated;
+atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
int tcp_memory_pressure __read_mostly;

-int *memory_pressure_tcp(struct mem_cgroup *sg)
+int *memory_pressure_tcp_nocg(struct mem_cgroup *sg)
{
return &tcp_memory_pressure;
}
-EXPORT_SYMBOL(memory_pressure_tcp);
+EXPORT_SYMBOL(memory_pressure_tcp_nocg);

-struct percpu_counter *sockets_allocated_tcp(struct mem_cgroup *sg)
+struct percpu_counter *sockets_allocated_tcp_nocg(struct mem_cgroup *sg)
{
return &tcp_sockets_allocated;
}
-EXPORT_SYMBOL(sockets_allocated_tcp);
+EXPORT_SYMBOL(sockets_allocated_tcp_nocg);

-void tcp_enter_memory_pressure(struct sock *sk)
+/*
+ * Pressure flag: try to collapse.
+ * Technical note: it is used by multiple contexts non atomically.
+ * All the __sk_mem_schedule() is of this nature: accounting
+ * is strict, actions are advisory and have some latency.
+ */
+void tcp_enter_memory_pressure_nocg(struct sock *sk)
{
if (!tcp_memory_pressure) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
tcp_memory_pressure = 1;
}
}
-EXPORT_SYMBOL(tcp_enter_memory_pressure);
+EXPORT_SYMBOL(tcp_enter_memory_pressure_nocg);

-long *tcp_sysctl_mem(struct mem_cgroup *sg)
+long *tcp_sysctl_mem_nocg(struct mem_cgroup *sg)
{
return sysctl_tcp_mem;
}
-EXPORT_SYMBOL(tcp_sysctl_mem);
+EXPORT_SYMBOL(tcp_sysctl_mem_nocg);

-atomic_long_t *memory_allocated_tcp(struct mem_cgroup *sg)
+atomic_long_t *memory_allocated_tcp_nocg(struct mem_cgroup *sg)
{
return &tcp_memory_allocated;
}
-EXPORT_SYMBOL(memory_allocated_tcp);
+EXPORT_SYMBOL(memory_allocated_tcp_nocg);

/* Convert seconds to retransmits based on initial and max timeout */
static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
@@ -3247,7 +3243,9 @@ void __init tcp_init(void)

BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));

+#ifndef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
percpu_counter_init(&tcp_sockets_allocated, 0);
+#endif
percpu_counter_init(&tcp_orphan_count, 0);
tcp_hashinfo.bind_bucket_cachep =
kmem_cache_create("tcp_bind_bucket",
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index cbb0d5e..c857baf 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2597,12 +2597,16 @@ struct proto tcp_prot = {
.hash = inet_hash,
.unhash = inet_unhash,
.get_port = inet_csk_get_port,
- .enter_memory_pressure = tcp_enter_memory_pressure,
- .memory_pressure = memory_pressure_tcp,
- .sockets_allocated = sockets_allocated_tcp,
+ .enter_memory_pressure = tcp_enter_memory_pressure_nocg,
+ .memory_pressure = memory_pressure_tcp_nocg,
+ .sockets_allocated = sockets_allocated_tcp_nocg,
.orphan_count = &tcp_orphan_count,
- .memory_allocated = memory_allocated_tcp,
- .prot_mem = tcp_sysctl_mem,
+ .memory_allocated = memory_allocated_tcp_nocg,
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ .init_cgroup = tcp_init_cgroup,
+ .destroy_cgroup = tcp_destroy_cgroup,
+#endif
+ .prot_mem = tcp_sysctl_mem_nocg,
.sysctl_wmem = sysctl_tcp_wmem,
.sysctl_rmem = sysctl_tcp_rmem,
.max_header = MAX_TCP_HEADER,
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 807797a..b2a2350 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -2220,12 +2220,16 @@ struct proto tcpv6_prot = {
.hash = tcp_v6_hash,
.unhash = inet_unhash,
.get_port = inet_csk_get_port,
- .enter_memory_pressure = tcp_enter_memory_pressure,
- .sockets_allocated = sockets_allocated_tcp,
- .memory_allocated = memory_allocated_tcp,
- .memory_pressure = memory_pressure_tcp,
+ .enter_memory_pressure = tcp_enter_memory_pressure_nocg,
+ .sockets_allocated = sockets_allocated_tcp_nocg,
+ .memory_allocated = memory_allocated_tcp_nocg,
+ .memory_pressure = memory_pressure_tcp_nocg,
.orphan_count = &tcp_orphan_count,
- .prot_mem = tcp_sysctl_mem,
+ .prot_mem = tcp_sysctl_mem_nocg,
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ .init_cgroup = tcp_init_cgroup_fill,
+ .destroy_cgroup = tcp_destroy_cgroup_fill,
+#endif
.sysctl_wmem = sysctl_tcp_wmem,
.sysctl_rmem = sysctl_tcp_rmem,
.max_header = MAX_TCP_HEADER,
--
1.7.6