foundations of per-cgroup memory pressure controlling.

This patch replaces all uses of struct sock fields' memory_pressure,
memory_allocated, sockets_allocated, and sysctl_mem to acessor
macros. Those macros can either receive a socket argument, or a mem_cgroup
argument, depending on the context they live in.

Since we're only doing a macro wrapping here, no performance impact at all is
expected in the case where we don't have cgroups disabled.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 97 insertions, 2 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 8ac338cb39c..ed0dbf03453 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -53,6 +53,7 @@
 #include <linux/security.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
+#include <linux/memcontrol.h>
 
 #include <linux/filter.h>
 #include <linux/rculist_nulls.h>
@@ -867,6 +868,99 @@ static inline void sk_refcnt_debug_release(const struct sock *sk)
 #define sk_refcnt_debug_release(sk) do { } while (0)
 #endif /* SOCK_REFCNT_DEBUG */
 
+static inline bool sk_has_memory_pressure(const struct sock *sk)
+{
+	return sk->sk_prot->memory_pressure != NULL;
+}
+
+static inline bool sk_under_memory_pressure(const struct sock *sk)
+{
+	if (!sk->sk_prot->memory_pressure)
+		return false;
+	return !!*sk->sk_prot->memory_pressure;
+}
+
+static inline void sk_leave_memory_pressure(struct sock *sk)
+{
+	int *memory_pressure = sk->sk_prot->memory_pressure;
+
+	if (memory_pressure && *memory_pressure)
+		*memory_pressure = 0;
+}
+
+static inline void sk_enter_memory_pressure(struct sock *sk)
+{
+	if (sk->sk_prot->enter_memory_pressure)
+		sk->sk_prot->enter_memory_pressure(sk);
+}
+
+static inline long sk_prot_mem_limits(const struct sock *sk, int index)
+{
+	long *prot = sk->sk_prot->sysctl_mem;
+	return prot[index];
+}
+
+static inline long
+sk_memory_allocated(const struct sock *sk)
+{
+	struct proto *prot = sk->sk_prot;
+	return atomic_long_read(prot->memory_allocated);
+}
+
+static inline long
+sk_memory_allocated_add(struct sock *sk, int amt)
+{
+	struct proto *prot = sk->sk_prot;
+	return atomic_long_add_return(amt, prot->memory_allocated);
+}
+
+static inline void
+sk_memory_allocated_sub(struct sock *sk, int amt)
+{
+	struct proto *prot = sk->sk_prot;
+	atomic_long_sub(amt, prot->memory_allocated);
+}
+
+static inline void sk_sockets_allocated_dec(struct sock *sk)
+{
+	struct proto *prot = sk->sk_prot;
+	percpu_counter_dec(prot->sockets_allocated);
+}
+
+static inline void sk_sockets_allocated_inc(struct sock *sk)
+{
+	struct proto *prot = sk->sk_prot;
+	percpu_counter_inc(prot->sockets_allocated);
+}
+
+static inline int
+sk_sockets_allocated_read_positive(struct sock *sk)
+{
+	struct proto *prot = sk->sk_prot;
+
+	return percpu_counter_sum_positive(prot->sockets_allocated);
+}
+
+static inline int
+proto_sockets_allocated_sum_positive(struct proto *prot)
+{
+	return percpu_counter_sum_positive(prot->sockets_allocated);
+}
+
+static inline long
+proto_memory_allocated(struct proto *prot)
+{
+	return atomic_long_read(prot->memory_allocated);
+}
+
+static inline bool
+proto_memory_pressure(struct proto *prot)
+{
+	if (!prot->memory_pressure)
+		return false;
+	return !!*prot->memory_pressure;
+}
+
 
 #ifdef CONFIG_PROC_FS
 /* Called with local bh disabled */
@@ -1674,7 +1768,7 @@ static inline struct page *sk_stream_alloc_page(struct sock *sk)
 
 	page = alloc_pages(sk->sk_allocation, 0);
 	if (!page) {
-		sk->sk_prot->enter_memory_pressure(sk);
+		sk_enter_memory_pressure(sk);
 		sk_stream_moderate_sndbuf(sk);
 	}
 	return page;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 02f070d339b..913473b4eda 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -44,6 +44,7 @@
 #include <net/dst.h>
 
 #include <linux/seq_file.h>
+#include <linux/memcontrol.h>
 
 extern struct inet_hashinfo tcp_hashinfo;
 
@@ -285,7 +286,7 @@ static inline bool tcp_too_many_orphans(struct sock *sk, int shift)
 	}
 
 	if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
-	    atomic_long_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])
+	    sk_memory_allocated(sk) > sk_prot_mem_limits(sk, 2))
 		return true;
 	return false;
 }