[PATCH 06/14] net: tcp_memcontrol: simplify the per-memcg limit access

Johannes Weiner
2015-12-08T15:31:08Z

tcp_memcontrol replicates the global sysctl_mem limit array per
cgroup, but it only ever sets these entries to the value of the
memory_allocated page_counter limit. Use the latter directly.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: David S. Miller <davem@davemloft.net>
---
include/linux/memcontrol.h | 1 -
include/net/sock.h | 8 +++++---
net/ipv4/tcp_memcontrol.c | 8 --------
3 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 1df8e89..be72aea 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -89,7 +89,6 @@ struct cg_proto {
struct page_counter memory_allocated; /* Current allocated memory. */
int memory_pressure;
bool active;
- long sysctl_mem[3];
/*
* memcg field is used to find which memcg we belong directly
* Each memcg struct can hold more than one cg_proto, so container_of
diff --git a/include/net/sock.h b/include/net/sock.h
index 7afbdab..0b333c2 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1159,10 +1159,12 @@ static inline void sk_enter_memory_pressure(struct sock *sk)

static inline long sk_prot_mem_limits(const struct sock *sk, int index)
{
- long *prot = sk->sk_prot->sysctl_mem;
+ long limit = sk->sk_prot->sysctl_mem[index];
+
if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
- prot = sk->sk_cgrp->sysctl_mem;
- return prot[index];
+ limit = min_t(long, limit, sk->sk_cgrp->memory_allocated.limit);
+
+ return limit;
}

static inline void memcg_memory_allocated_add(struct cg_proto *prot,
diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
index 6759e0d..ef4268d 100644
--- a/net/ipv4/tcp_memcontrol.c
+++ b/net/ipv4/tcp_memcontrol.c
@@ -21,9 +21,6 @@ int tcp_init_cgroup(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
if (!cg_proto)
return 0;

- cg_proto->sysctl_mem[0] = sysctl_tcp_mem[0];
- cg_proto->sysctl_mem[1] = sysctl_tcp_mem[1];
- cg_proto->sysctl_mem[2] = sysctl_tcp_mem[2];
cg_proto->memory_pressure = 0;
cg_proto->memcg = memcg;

@@ -54,7 +51,6 @@ EXPORT_SYMBOL(tcp_destroy_cgroup);
static int tcp_update_limit(struct mem_cgroup *memcg, unsigned long nr_pages)
{
struct cg_proto *cg_proto;
- int i;
int ret;

cg_proto = tcp_prot.proto_cgroup(memcg);
@@ -65,10 +61,6 @@ static int tcp_update_limit(struct mem_cgroup *memcg, unsigned long nr_pages)
if (ret)
return ret;

- for (i = 0; i < 3; i++)
- cg_proto->sysctl_mem[i] = min_t(long, nr_pages,
- sysctl_tcp_mem[i]);
-
if (!cg_proto->active) {
/*
* The active flag needs to be written after the static_key
--
2.6.3