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>

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;

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;
 }

net/core/sock.c

@@ -1323,7 +1323,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
 		newsk->sk_wq = NULL;
 
 		if (newsk->sk_prot->sockets_allocated)
-			percpu_counter_inc(newsk->sk_prot->sockets_allocated);
+			sk_sockets_allocated_inc(newsk);
 
 		if (newsk->sk_flags & SK_FLAGS_TIMESTAMP)
 			net_enable_timestamp();
@@ -1713,28 +1713,28 @@ int __sk_mem_schedule(struct sock *sk, int size, int kind)
 	long allocated;
 
 	sk->sk_forward_alloc += amt * SK_MEM_QUANTUM;
-	allocated = atomic_long_add_return(amt, prot->memory_allocated);
+
+	allocated = sk_memory_allocated_add(sk, amt);
 
 	/* Under limit. */
-	if (allocated <= prot->sysctl_mem[0]) {
-		if (prot->memory_pressure && *prot->memory_pressure)
-			*prot->memory_pressure = 0;
+	if (allocated <= sk_prot_mem_limits(sk, 0)) {
+		sk_leave_memory_pressure(sk);
 		return 1;
 	}
 
 	/* Under pressure. */
-	if (allocated > prot->sysctl_mem[1])
-		if (prot->enter_memory_pressure)
-			prot->enter_memory_pressure(sk);
+	if (allocated > sk_prot_mem_limits(sk, 1))
+		sk_enter_memory_pressure(sk);
 
 	/* Over hard limit. */
-	if (allocated > prot->sysctl_mem[2])
+	if (allocated > sk_prot_mem_limits(sk, 2))
 		goto suppress_allocation;
 
 	/* guarantee minimum buffer size under pressure */
 	if (kind == SK_MEM_RECV) {
 		if (atomic_read(&sk->sk_rmem_alloc) < prot->sysctl_rmem[0])
 			return 1;
+
 	} else { /* SK_MEM_SEND */
 		if (sk->sk_type == SOCK_STREAM) {
 			if (sk->sk_wmem_queued < prot->sysctl_wmem[0])
@@ -1744,13 +1744,13 @@ int __sk_mem_schedule(struct sock *sk, int size, int kind)
 				return 1;
 	}
 
-	if (prot->memory_pressure) {
+	if (sk_has_memory_pressure(sk)) {
 		int alloc;
 
-		if (!*prot->memory_pressure)
+		if (!sk_under_memory_pressure(sk))
 			return 1;
-		alloc = percpu_counter_read_positive(prot->sockets_allocated);
-		if (prot->sysctl_mem[2] > alloc *
+		alloc = sk_sockets_allocated_read_positive(sk);
+		if (sk_prot_mem_limits(sk, 2) > alloc *
 		    sk_mem_pages(sk->sk_wmem_queued +
 				 atomic_read(&sk->sk_rmem_alloc) +
 				 sk->sk_forward_alloc))
@@ -1773,7 +1773,9 @@ int __sk_mem_schedule(struct sock *sk, int size, int kind)
 
 	/* Alas. Undo changes. */
 	sk->sk_forward_alloc -= amt * SK_MEM_QUANTUM;
-	atomic_long_sub(amt, prot->memory_allocated);
+
+	sk_memory_allocated_sub(sk, amt);
+
 	return 0;
 }
 EXPORT_SYMBOL(__sk_mem_schedule);
@@ -1784,15 +1786,13 @@ EXPORT_SYMBOL(__sk_mem_schedule);
  */
 void __sk_mem_reclaim(struct sock *sk)
 {
-	struct proto *prot = sk->sk_prot;
-
-	atomic_long_sub(sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT,
-		   prot->memory_allocated);
+	sk_memory_allocated_sub(sk,
+				sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT);
 	sk->sk_forward_alloc &= SK_MEM_QUANTUM - 1;
 
-	if (prot->memory_pressure && *prot->memory_pressure &&
-	    (atomic_long_read(prot->memory_allocated) < prot->sysctl_mem[0]))
-		*prot->memory_pressure = 0;
+	if (sk_under_memory_pressure(sk) &&
+	    (sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0)))
+		sk_leave_memory_pressure(sk);
 }
 EXPORT_SYMBOL(__sk_mem_reclaim);
 
@@ -2507,16 +2507,27 @@ static char proto_method_implemented(const void *method)
 {
 	return method == NULL ? 'n' : 'y';
 }
+static long sock_prot_memory_allocated(struct proto *proto)
+{
+	return proto->memory_allocated != NULL ? proto_memory_allocated(proto): -1L;
+}
+
+static char *sock_prot_memory_pressure(struct proto *proto)
+{
+	return proto->memory_pressure != NULL ?
+	proto_memory_pressure(proto) ? "yes" : "no" : "NI";
+}
 
 static void proto_seq_printf(struct seq_file *seq, struct proto *proto)
 {
+
 	seq_printf(seq, "%-9s %4u %6d  %6ld   %-3s %6u   %-3s  %-10s "
 			"%2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c\n",
 		   proto->name,
 		   proto->obj_size,
 		   sock_prot_inuse_get(seq_file_net(seq), proto),
-		   proto->memory_allocated != NULL ? atomic_long_read(proto->memory_allocated) : -1L,
-		   proto->memory_pressure != NULL ? *proto->memory_pressure ? "yes" : "no" : "NI",
+		   sock_prot_memory_allocated(proto),
+		   sock_prot_memory_pressure(proto),
 		   proto->max_header,
 		   proto->slab == NULL ? "no" : "yes",
 		   module_name(proto->owner),

net/ipv4/proc.c

@@ -56,17 +56,17 @@ static int sockstat_seq_show(struct seq_file *seq, void *v)
 
 	local_bh_disable();
 	orphans = percpu_counter_sum_positive(&tcp_orphan_count);
-	sockets = percpu_counter_sum_positive(&tcp_sockets_allocated);
+	sockets = proto_sockets_allocated_sum_positive(&tcp_prot);
 	local_bh_enable();
 
 	socket_seq_show(seq);
 	seq_printf(seq, "TCP: inuse %d orphan %d tw %d alloc %d mem %ld\n",
 		   sock_prot_inuse_get(net, &tcp_prot), orphans,
 		   tcp_death_row.tw_count, sockets,
-		   atomic_long_read(&tcp_memory_allocated));
+		   proto_memory_allocated(&tcp_prot));
 	seq_printf(seq, "UDP: inuse %d mem %ld\n",
 		   sock_prot_inuse_get(net, &udp_prot),
-		   atomic_long_read(&udp_memory_allocated));
+		   proto_memory_allocated(&udp_prot));
 	seq_printf(seq, "UDPLITE: inuse %d\n",
 		   sock_prot_inuse_get(net, &udplite_prot));
 	seq_printf(seq, "RAW: inuse %d\n",

net/ipv4/tcp_input.c

@@ -322,7 +322,7 @@ static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb)
 	/* Check #1 */
 	if (tp->rcv_ssthresh < tp->window_clamp &&
 	    (int)tp->rcv_ssthresh < tcp_space(sk) &&
-	    !tcp_memory_pressure) {
+	    !sk_under_memory_pressure(sk)) {
 		int incr;
 
 		/* Check #2. Increase window, if skb with such overhead
@@ -411,8 +411,8 @@ static void tcp_clamp_window(struct sock *sk)
 
 	if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] &&
 	    !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&
-	    !tcp_memory_pressure &&
-	    atomic_long_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {
+	    !sk_under_memory_pressure(sk) &&
+	    sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0)) {
 		sk->sk_rcvbuf = min(atomic_read(&sk->sk_rmem_alloc),
 				    sysctl_tcp_rmem[2]);
 	}
@@ -4866,7 +4866,7 @@ static int tcp_prune_queue(struct sock *sk)
 
 	if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
 		tcp_clamp_window(sk);
-	else if (tcp_memory_pressure)
+	else if (sk_under_memory_pressure(sk))
 		tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss);
 
 	tcp_collapse_ofo_queue(sk);
@@ -4932,11 +4932,11 @@ static int tcp_should_expand_sndbuf(const struct sock *sk)
 		return 0;
 
 	/* If we are under global TCP memory pressure, do not expand.  */
-	if (tcp_memory_pressure)
+	if (sk_under_memory_pressure(sk))
 		return 0;
 
 	/* If we are under soft global TCP memory pressure, do not expand.  */
-	if (atomic_long_read(&tcp_memory_allocated) >= sysctl_tcp_mem[0])
+	if (sk_memory_allocated(sk) >= sk_prot_mem_limits(sk, 0))
 		return 0;
 
 	/* If we filled the congestion window, do not expand.  */

net/ipv4/tcp_ipv4.c

@@ -1917,7 +1917,7 @@ static int tcp_v4_init_sock(struct sock *sk)
 	sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 
 	local_bh_disable();
-	percpu_counter_inc(&tcp_sockets_allocated);
+	sk_sockets_allocated_inc(sk);
 	local_bh_enable();
 
 	return 0;
@@ -1973,7 +1973,7 @@ void tcp_v4_destroy_sock(struct sock *sk)
 		tp->cookie_values = NULL;
 	}
 
-	percpu_counter_dec(&tcp_sockets_allocated);
+	sk_sockets_allocated_dec(sk);
 }
 EXPORT_SYMBOL(tcp_v4_destroy_sock);
 

net/ipv4/tcp_output.c

@@ -1922,7 +1922,7 @@ u32 __tcp_select_window(struct sock *sk)
 	if (free_space < (full_space >> 1)) {
 		icsk->icsk_ack.quick = 0;
 
-		if (tcp_memory_pressure)
+		if (sk_under_memory_pressure(sk))
 			tp->rcv_ssthresh = min(tp->rcv_ssthresh,
 					       4U * tp->advmss);
 

net/ipv4/tcp_timer.c

@@ -261,7 +261,7 @@ static void tcp_delack_timer(unsigned long data)
 	}
 
 out:
-	if (tcp_memory_pressure)
+	if (sk_under_memory_pressure(sk))
 		sk_mem_reclaim(sk);
 out_unlock:
 	bh_unlock_sock(sk);

net/ipv6/tcp_ipv6.c

@@ -1994,7 +1994,7 @@ static int tcp_v6_init_sock(struct sock *sk)
 	sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 
 	local_bh_disable();
-	percpu_counter_inc(&tcp_sockets_allocated);
+	sk_sockets_allocated_inc(sk);
 	local_bh_enable();
 
 	return 0;