From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH v3 net-next] tcp: TCP Small Queues
Date: Wed, 11 Jul 2012 11:38:31 -0700
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References: <1342021831.3265.8174.camel@edumazet-glaptop>
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Cc: David Miller <davem@davemloft.net>, nanditad@google.com,
	netdev@vger.kernel.org, codel@lists.bufferbloat.net,
	ncardwell@google.com, mattmathis@google.com
To: Eric Dumazet <eric.dumazet@gmail.com>
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In-Reply-To: <1342021831.3265.8174.camel@edumazet-glaptop> (Eric Dumazet's
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Eric Dumazet <eric.dumazet@gmail.com> writes:
> +
> +		if (!sock_owned_by_user(sk)) {
> +			if ((1 << sk->sk_state) &
> +			    (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 |
> +			     TCPF_CLOSING | TCPF_CLOSE_WAIT))
> +				tcp_write_xmit(sk,
> +					       tcp_current_mss(sk),
> +					       0, 0,
> +					       GFP_ATOMIC);

Did you have any problems with the GFP_ATOMIC allocation failing here?
I think you move some skb allocs from process context to ATOMIC, right?

It relies on the VM somehow catching up in another context.

May be interesting to try out under very high memory pressure.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only