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Commit b8da51eb authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: introduce tcp_under_memory_pressure() 



Introduce an optimized version of sk_under_memory_pressure()
for TCP. Our intent is to use it in fast paths.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a6c5ea4c

include/net/tcp.h

+8 −0
Original line number Diff line number Diff line
@@ -286,6 +286,14 @@ extern atomic_long_t tcp_memory_allocated; 
extern struct percpu_counter tcp_sockets_allocated;

extern int tcp_memory_pressure;



/* optimized version of sk_under_memory_pressure() for TCP sockets */

static inline bool tcp_under_memory_pressure(const struct sock *sk)

{

	if (mem_cgroup_sockets_enabled && sk->sk_cgrp)

		return !!sk->sk_cgrp->memory_pressure;



	return tcp_memory_pressure;

}

/*

 * The next routines deal with comparing 32 bit unsigned ints

 * and worry about wraparound (automatic with unsigned arithmetic).

net/ipv4/tcp_input.c

+4 −4
Original line number Diff line number Diff line
@@ -359,7 +359,7 @@ 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) &&

	    !sk_under_memory_pressure(sk)) {

	    !tcp_under_memory_pressure(sk)) {

		int incr;



		/* Check #2. Increase window, if skb with such overhead
@@ -446,7 +446,7 @@ static void tcp_clamp_window(struct sock *sk) 


	if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] &&

	    !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&

	    !sk_under_memory_pressure(sk) &&

	    !tcp_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]);
@@ -4781,7 +4781,7 @@ static int tcp_prune_queue(struct sock *sk) 


	if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)

		tcp_clamp_window(sk);

	else if (sk_under_memory_pressure(sk))

	else if (tcp_under_memory_pressure(sk))

		tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss);



	tcp_collapse_ofo_queue(sk);
@@ -4825,7 +4825,7 @@ static bool tcp_should_expand_sndbuf(const struct sock *sk) 
		return false;



	/* If we are under global TCP memory pressure, do not expand.  */

	if (sk_under_memory_pressure(sk))

	if (tcp_under_memory_pressure(sk))

		return false;



	/* If we are under soft global TCP memory pressure, do not expand.  */

net/ipv4/tcp_output.c

+2 −2
Original line number Diff line number Diff line
@@ -2392,7 +2392,7 @@ u32 __tcp_select_window(struct sock *sk) 
	if (free_space < (full_space >> 1)) {

		icsk->icsk_ack.quick = 0;



		if (sk_under_memory_pressure(sk))

		if (tcp_under_memory_pressure(sk))

			tp->rcv_ssthresh = min(tp->rcv_ssthresh,

					       4U * tp->advmss);
@@ -2843,7 +2843,7 @@ void tcp_send_fin(struct sock *sk) 
	 * Note: in the latter case, FIN packet will be sent after a timeout,

	 * as TCP stack thinks it has already been transmitted.

	 */

	if (tskb && (tcp_send_head(sk) || sk_under_memory_pressure(sk))) {

	if (tskb && (tcp_send_head(sk) || tcp_under_memory_pressure(sk))) {

coalesce:

		TCP_SKB_CB(tskb)->tcp_flags |= TCPHDR_FIN;

		TCP_SKB_CB(tskb)->end_seq++;

net/ipv4/tcp_timer.c

+1 −1
Original line number Diff line number Diff line
@@ -247,7 +247,7 @@ void tcp_delack_timer_handler(struct sock *sk) 
	}



out:

	if (sk_under_memory_pressure(sk))

	if (tcp_under_memory_pressure(sk))

		sk_mem_reclaim(sk);

}