[NET]: Compact sk_stream_mem_schedule() code

This function references sk->sk_prot->xxx for many times.
It turned out, that there's so many code in it, that gcc
cannot always optimize access to sk->sk_prot's fields.

After saving the sk->sk_prot on the stack and comparing
disassembled code, it turned out that the function became
~10 bytes shorter and made less dereferences (on i386 and
x86_64). Stack consumption didn't grow.

Besides, this patch drives most of this function into the
80 columns limit.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/stream.c b/net/core/stream.c
index 755bacb..b2fb846 100644 (file)
--- a/net/core/stream.c
+++ b/net/core/stream.c
@@ -210,35 +210,36 @@ EXPORT_SYMBOL(__sk_stream_mem_reclaim);
 int sk_stream_mem_schedule(struct sock *sk, int size, int kind)
 {
        int amt = sk_stream_pages(size);
+       struct proto *prot = sk->sk_prot;
 
        sk->sk_forward_alloc += amt * SK_STREAM_MEM_QUANTUM;
-       atomic_add(amt, sk->sk_prot->memory_allocated);
+       atomic_add(amt, prot->memory_allocated);
 
        /* Under limit. */
-       if (atomic_read(sk->sk_prot->memory_allocated) < sk->sk_prot->sysctl_mem[0]) {
-               if (*sk->sk_prot->memory_pressure)
-                       *sk->sk_prot->memory_pressure = 0;
+       if (atomic_read(prot->memory_allocated) < prot->sysctl_mem[0]) {
+               if (*prot->memory_pressure)
+                       *prot->memory_pressure = 0;
                return 1;
        }
 
        /* Over hard limit. */
-       if (atomic_read(sk->sk_prot->memory_allocated) > sk->sk_prot->sysctl_mem[2]) {
-               sk->sk_prot->enter_memory_pressure();
+       if (atomic_read(prot->memory_allocated) > prot->sysctl_mem[2]) {
+               prot->enter_memory_pressure();
                goto suppress_allocation;
        }
 
        /* Under pressure. */
-       if (atomic_read(sk->sk_prot->memory_allocated) > sk->sk_prot->sysctl_mem[1])
-               sk->sk_prot->enter_memory_pressure();
+       if (atomic_read(prot->memory_allocated) > prot->sysctl_mem[1])
+               prot->enter_memory_pressure();
 
        if (kind) {
-               if (atomic_read(&sk->sk_rmem_alloc) < sk->sk_prot->sysctl_rmem[0])
+               if (atomic_read(&sk->sk_rmem_alloc) < prot->sysctl_rmem[0])
                        return 1;
-       } else if (sk->sk_wmem_queued < sk->sk_prot->sysctl_wmem[0])
+       } else if (sk->sk_wmem_queued < prot->sysctl_wmem[0])
                return 1;
 
-       if (!*sk->sk_prot->memory_pressure ||
-           sk->sk_prot->sysctl_mem[2] > atomic_read(sk->sk_prot->sockets_allocated) *
+       if (!*prot->memory_pressure ||
+           prot->sysctl_mem[2] > atomic_read(prot->sockets_allocated) *
                                sk_stream_pages(sk->sk_wmem_queued +
                                                atomic_read(&sk->sk_rmem_alloc) +
                                                sk->sk_forward_alloc))
@@ -258,7 +259,7 @@ suppress_allocation:
 
        /* Alas. Undo changes. */
        sk->sk_forward_alloc -= amt * SK_STREAM_MEM_QUANTUM;
-       atomic_sub(amt, sk->sk_prot->memory_allocated);
+       atomic_sub(amt, prot->memory_allocated);
        return 0;
 }