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tcp: introduce tcp_under_memory_pressure()

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

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-05-15 12:39:27 -07:00 committed by David S. Miller
parent a6c5ea4ccf
commit b8da51ebb1
4 changed files with 15 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

8
include/net/tcp.h
View file

@ -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).

8
net/ipv4/tcp_input.c
View file

@ -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. */

4
net/ipv4/tcp_output.c
View file

@ -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++;

2
net/ipv4/tcp_timer.c
View file

@ -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);
}