From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E632C43603 for ; Wed, 11 Dec 2019 15:24:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 16C6D2077B for ; Wed, 11 Dec 2019 15:24:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576077843; bh=03Nh+NVS2P8g7+6KLFx/BlAGRm0adVFqyvzFBF/ZCaM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=g8Kj0V4dif3PHsOdUAfO0KB7x3Htl9QQU6YXW2xCPdr5LZm0Ylq7gBozQkgYrOKmN ViE9XnMrle87HyJuIx/g44ZpMJL2BBzTAfjAcDnB1C+ksVpGsN2AkEKbyC9SmrE3Fo jfq8T7vOjWZ895NgkA5cdJG370UFNuGuPXPOdZ+Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732419AbfLKPYC (ORCPT ); Wed, 11 Dec 2019 10:24:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:55136 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732420AbfLKPX4 (ORCPT ); Wed, 11 Dec 2019 10:23:56 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D73A42077B; Wed, 11 Dec 2019 15:23:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576077836; bh=03Nh+NVS2P8g7+6KLFx/BlAGRm0adVFqyvzFBF/ZCaM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mnoiHWbIuHOwfO2HdaER92CO44znXNosQZdYuqWg2UWwnc3W1W4W+8dAz/iCAsP6Y JdUY/btaN7URUeu9ybEDOvJ/o3e1qt0rw50Z2QyRg0ar2/d6VOcqZcOOfiyLzB8siY VBWPISwzMcexe05x1EY1mP5vMrvJVgmo4UZipqXI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jean-Louis Dupond , Eric Dumazet , Neal Cardwell , Yuchung Cheng , "David S. Miller" , Sasha Levin Subject: [PATCH 4.19 152/243] tcp: make tcp_space() aware of socket backlog Date: Wed, 11 Dec 2019 16:05:14 +0100 Message-Id: <20191211150349.433232970@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191211150339.185439726@linuxfoundation.org> References: <20191211150339.185439726@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet [ Upstream commit 85bdf7db5b53cdcc7a901db12bcb3d0063e3866d ] Jean-Louis Dupond reported poor iscsi TCP receive performance that we tracked to backlog drops. Apparently we fail to send window updates reflecting the fact that we are under stress. Note that we might lack a proper window increase when backlog is fully processed, since __release_sock() clears sk->sk_backlog.len _after_ all skbs have been processed. This should not matter in practice. If we had a significant load through socket backlog, we are in a dangerous situation. Reported-by: Jean-Louis Dupond Signed-off-by: Eric Dumazet Acked-by: Neal Cardwell Acked-by: Yuchung Cheng Tested-by: Jean-Louis Dupond Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/tcp.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index abcf53a6db045..3f4223a550d92 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1353,7 +1353,7 @@ static inline int tcp_win_from_space(const struct sock *sk, int space) /* Note: caller must be prepared to deal with negative returns */ static inline int tcp_space(const struct sock *sk) { - return tcp_win_from_space(sk, sk->sk_rcvbuf - + return tcp_win_from_space(sk, sk->sk_rcvbuf - sk->sk_backlog.len - atomic_read(&sk->sk_rmem_alloc)); } -- 2.20.1