Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8e165e20 authored by Florian Westphal's avatar Florian Westphal Committed by David S. Miller
Browse files

net: tcp: add mib counters to track zero window transitions 



Three counters are added:
- one to track when we went from non-zero to zero window
- one to track the reverse
- one counter incremented when we want to announce zero window,
  but can't because we would shrink current window.

Suggested-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2ebe21fd

include/uapi/linux/snmp.h

+3 −0
Original line number Diff line number Diff line
@@ -259,6 +259,9 @@ enum 
	LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES, /* TCPSpuriousRtxHostQueues */

	LINUX_MIB_BUSYPOLLRXPACKETS,		/* BusyPollRxPackets */

	LINUX_MIB_TCPAUTOCORKING,		/* TCPAutoCorking */

	LINUX_MIB_TCPFROMZEROWINDOWADV,		/* TCPFromZeroWindowAdv */

	LINUX_MIB_TCPTOZEROWINDOWADV,		/* TCPToZeroWindowAdv */

	LINUX_MIB_TCPWANTZEROWINDOWADV,		/* TCPWantZeroWindowAdv */

	__LINUX_MIB_MAX

};

net/ipv4/proc.c

+3 −0
Original line number Diff line number Diff line
@@ -280,6 +280,9 @@ static const struct snmp_mib snmp4_net_list[] = { 
	SNMP_MIB_ITEM("TCPSpuriousRtxHostQueues", LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES),

	SNMP_MIB_ITEM("BusyPollRxPackets", LINUX_MIB_BUSYPOLLRXPACKETS),

	SNMP_MIB_ITEM("TCPAutoCorking", LINUX_MIB_TCPAUTOCORKING),

	SNMP_MIB_ITEM("TCPFromZeroWindowAdv", LINUX_MIB_TCPFROMZEROWINDOWADV),

	SNMP_MIB_ITEM("TCPToZeroWindowAdv", LINUX_MIB_TCPTOZEROWINDOWADV),

	SNMP_MIB_ITEM("TCPWantZeroWindowAdv", LINUX_MIB_TCPWANTZEROWINDOWADV),

	SNMP_MIB_SENTINEL

};

net/ipv4/tcp_output.c

+11 −1
Original line number Diff line number Diff line
@@ -269,6 +269,7 @@ EXPORT_SYMBOL(tcp_select_initial_window); 
static u16 tcp_select_window(struct sock *sk)

{

	struct tcp_sock *tp = tcp_sk(sk);

	u32 old_win = tp->rcv_wnd;

	u32 cur_win = tcp_receive_window(tp);

	u32 new_win = __tcp_select_window(sk);
@@ -281,6 +282,9 @@ static u16 tcp_select_window(struct sock *sk) 
		 *

		 * Relax Will Robinson.

		 */

		if (new_win == 0)

			NET_INC_STATS(sock_net(sk),

				      LINUX_MIB_TCPWANTZEROWINDOWADV);

		new_win = ALIGN(cur_win, 1 << tp->rx_opt.rcv_wscale);

	}

	tp->rcv_wnd = new_win;
@@ -298,8 +302,14 @@ static u16 tcp_select_window(struct sock *sk) 
	new_win >>= tp->rx_opt.rcv_wscale;



	/* If we advertise zero window, disable fast path. */

	if (new_win == 0)

	if (new_win == 0) {

		tp->pred_flags = 0;

		if (old_win)

			NET_INC_STATS(sock_net(sk),

				      LINUX_MIB_TCPTOZEROWINDOWADV);

	} else if (old_win == 0) {

		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFROMZEROWINDOWADV);

	}



	return new_win;

}