From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756923Ab3AICyr (ORCPT ); Tue, 8 Jan 2013 21:54:47 -0500 Received: from mail-pa0-f50.google.com ([209.85.220.50]:49700 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756271Ab3AICyp (ORCPT ); Tue, 8 Jan 2013 21:54:45 -0500 Subject: Re: ppoll() stuck on POLLIN while TCP peer is sending From: Eric Dumazet To: Eric Wong , Mel Gorman Cc: linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Rik van Riel , Minchan Kim , Andrew Morton , Linus Torvalds In-Reply-To: <1357698749.27446.6.camel@edumazet-glaptop> References: <20121228014503.GA5017@dcvr.yhbt.net> <20130102200848.GA4500@dcvr.yhbt.net> <20130104160148.GB3885@suse.de> <20130106120700.GA24671@dcvr.yhbt.net> <20130107122516.GC3885@suse.de> <20130107223850.GA21311@dcvr.yhbt.net> <20130108224313.GA13304@suse.de> <20130108232325.GA5948@dcvr.yhbt.net> <1357697647.18156.1217.camel@edumazet-glaptop> <1357698749.27446.6.camel@edumazet-glaptop> Content-Type: text/plain; charset="UTF-8" Date: Tue, 08 Jan 2013 18:54:42 -0800 Message-ID: <1357700082.27446.11.camel@edumazet-glaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2013-01-08 at 18:32 -0800, Eric Dumazet wrote: > > Hmm, it seems sk_filter() can return -ENOMEM because skb has the > pfmemalloc() set. > > One TCP socket keeps retransmitting an SKB via loopback, and TCP stack > drops the packet again and again. sock_init_data() sets sk->sk_allocation to GFP_KERNEL Shouldnt it use (GFP_KERNEL | __GFP_NOMEMALLOC) instead ? diff --git a/net/core/sock.c b/net/core/sock.c index bc131d4..76c4b39 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -286,6 +286,7 @@ void sk_set_memalloc(struct sock *sk) { sock_set_flag(sk, SOCK_MEMALLOC); sk->sk_allocation |= __GFP_MEMALLOC; + sk->sk_allocation &= ~__GFP_NOMEMALLOC; static_key_slow_inc(&memalloc_socks); } EXPORT_SYMBOL_GPL(sk_set_memalloc); @@ -294,6 +295,7 @@ void sk_clear_memalloc(struct sock *sk) { sock_reset_flag(sk, SOCK_MEMALLOC); sk->sk_allocation &= ~__GFP_MEMALLOC; + sk->sk_allocation |= __GFP_NOMEMALLOC; static_key_slow_dec(&memalloc_socks); /* @@ -2230,7 +2232,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) init_timer(&sk->sk_timer); - sk->sk_allocation = GFP_KERNEL; + sk->sk_allocation = GFP_KERNEL | __GFP_NOMEMALLOC; sk->sk_rcvbuf = sysctl_rmem_default; sk->sk_sndbuf = sysctl_wmem_default; sk->sk_state = TCP_CLOSE;