+/**
+ * __sk_mem_schedule - increase sk_forward_alloc and memory_allocated
+ * @sk: socket
+ * @size: memory size to allocate
+ * @kind: allocation type
+ *
+ * If kind is SK_MEM_SEND, it means wmem allocation. Otherwise it means
+ * rmem allocation. This function assumes that protocols which have
+ * memory_pressure use sk_wmem_queued as write buffer accounting.
+ */
+int __sk_mem_schedule(struct sock *sk, int size, int kind)
+{
+ struct proto *prot = sk->sk_prot;
+ int amt = sk_mem_pages(size);
+ int allocated;
+
+ sk->sk_forward_alloc += amt * SK_MEM_QUANTUM;
+ allocated = atomic_add_return(amt, prot->memory_allocated);
+
+ /* Under limit. */
+ if (allocated <= prot->sysctl_mem[0]) {
+ if (prot->memory_pressure && *prot->memory_pressure)
+ *prot->memory_pressure = 0;
+ return 1;
+ }
+
+ /* Under pressure. */
+ if (allocated > prot->sysctl_mem[1])
+ if (prot->enter_memory_pressure)
+ prot->enter_memory_pressure();
+
+ /* Over hard limit. */
+ if (allocated > prot->sysctl_mem[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])
+ return 1;
+ } else if (atomic_read(&sk->sk_wmem_alloc) <
+ prot->sysctl_wmem[0])
+ return 1;
+ }
+
+ if (prot->memory_pressure) {
+ if (!*prot->memory_pressure ||
+ prot->sysctl_mem[2] > atomic_read(prot->sockets_allocated) *
+ sk_mem_pages(sk->sk_wmem_queued +
+ atomic_read(&sk->sk_rmem_alloc) +
+ sk->sk_forward_alloc))
+ return 1;
+ }
+
+suppress_allocation:
+
+ if (kind == SK_MEM_SEND && sk->sk_type == SOCK_STREAM) {
+ sk_stream_moderate_sndbuf(sk);
+
+ /* Fail only if socket is _under_ its sndbuf.
+ * In this case we cannot block, so that we have to fail.
+ */
+ if (sk->sk_wmem_queued + size >= sk->sk_sndbuf)
+ return 1;
+ }
+
+ /* Alas. Undo changes. */
+ sk->sk_forward_alloc -= amt * SK_MEM_QUANTUM;
+ atomic_sub(amt, prot->memory_allocated);
+ return 0;
+}
+
+EXPORT_SYMBOL(__sk_mem_schedule);
+
+/**
+ * __sk_reclaim - reclaim memory_allocated
+ * @sk: socket
+ */
+void __sk_mem_reclaim(struct sock *sk)
+{
+ struct proto *prot = sk->sk_prot;
+
+ atomic_sub(sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT,
+ prot->memory_allocated);
+ sk->sk_forward_alloc &= SK_MEM_QUANTUM - 1;
+
+ if (prot->memory_pressure && *prot->memory_pressure &&
+ (atomic_read(prot->memory_allocated) < prot->sysctl_mem[0]))
+ *prot->memory_pressure = 0;
+}
+
+EXPORT_SYMBOL(__sk_mem_reclaim);
+
+