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Commit 9859a790 authored Nov 19, 2007 by Pavel Emelyanov Committed by David S. Miller Jan 28, 2008

[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>

parent 3ef1355d

net/core/stream.c

+14 −13

Original line number	Diff line number	Diff line
		@@ -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;
		}