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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9E63C433F5 for ; Fri, 6 May 2022 20:31:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1442925AbiEFUfF (ORCPT ); Fri, 6 May 2022 16:35:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344781AbiEFUe7 (ORCPT ); Fri, 6 May 2022 16:34:59 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9AE496D3A9 for ; Fri, 6 May 2022 13:31:14 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id p6so7987199pjm.1 for ; Fri, 06 May 2022 13:31:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=i3Ntzrv5FDfp2eYpZMiopVYr18OlFo4VdjXUK7cfBPU=; b=O85NYqjWtDow9jeD3TU4kt+F6nWSDZskBn/bCqCnzjrY0EvFfS6+VN0I/1Ug/g1LlB 2DVu+gjTG6VequvguY9OTwOg7lx0M0Xei4zmUF4J4To6SZXF6OW0pjPQW5tz+1JziBPu oAJNATpkVHBP2oxE9oggwFfFpeNIqI32ZBDazGe4aKFySi23y67jZQdGZ6KpNArR7aoZ 0i6l0s63jE1++BzSxYYsV+zeDutL3ni1k8+8pceZ20jUE70PsJEd49T6CNzTWMAJwSHr kUxbtMyHSumwabqi2UDYAMg4eCWPDRMdgx9HLIxktjj1lcJKVf9rUGHfqG/aHVsWek4T TcLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=i3Ntzrv5FDfp2eYpZMiopVYr18OlFo4VdjXUK7cfBPU=; b=WRV85Otao8yOpB+N2k6GC/dy/iq16M9hlSkZCQzEWtTjoKTdZBOntTEjaEFunzpnw4 UUzvHN/JsWh7lXETqstFTrmoVy7Ou/YY003wdJg2uiGCk2um3x+dYIklW2+6GoozuZJ9 fFv/ln8XU4/l7GmXYmhdexWj02i6dEFcFsqoKYa3+rnF6kXdaAabMYArfxv3EgjtIl0u qFatOEi0b7ofY/i8afUgC/zA+6b7NTQBbELX87mO0v+AOd9ox21KlWRfpdQLO5xgGIHb 8NiKoHz6EUoAh4s3mUrgh9cmcDhEHjWJGH9/GTYNxEm5qEIaWdDPD6k4PfxeicZ+snk2 RlDw== X-Gm-Message-State: AOAM531b6LjWywzAspNWrwSV/Z4DBD1UQaJHOEmZznYPLrVBUV+wnzBj 6PXjpHQc2VlfEwcnz2oAzwFQKVf6BR8zzw== X-Google-Smtp-Source: ABdhPJyUnf/2IAy1zjU8UQe87XfdGkBcgm1RleycVg7wfOu86v/fVUxrm5PQSkosijGggjbgCRfX4w== X-Received: by 2002:a17:902:c952:b0:15e:89be:49ea with SMTP id i18-20020a170902c95200b0015e89be49eamr5571513pla.32.1651869074157; Fri, 06 May 2022 13:31:14 -0700 (PDT) Received: from hermes.local (204-195-112-199.wavecable.com. [204.195.112.199]) by smtp.gmail.com with ESMTPSA id b7-20020aa79507000000b0050dc7628163sm3822221pfp.61.2022.05.06.13.31.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 May 2022 13:31:13 -0700 (PDT) Date: Fri, 6 May 2022 13:31:11 -0700 From: Stephen Hemminger To: Peilin Ye Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Hideaki YOSHIFUJI , David Ahern , Jamal Hadi Salim , Cong Wang , Jiri Pirko , Peilin Ye , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Cong Wang Subject: Re: [PATCH RFC v1 net-next 1/4] net: Introduce Qdisc backpressure infrastructure Message-ID: <20220506133111.1d4bebf3@hermes.local> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 6 May 2022 12:44:22 -0700 Peilin Ye wrote: > +static inline void qdisc_backpressure_overlimit(struct Qdisc *sch, struct sk_buff *skb) > +{ > + struct sock *sk = skb->sk; > + > + if (!sk || !sk_fullsock(sk)) > + return; > + > + if (cmpxchg(&sk->sk_backpressure_status, SK_UNTHROTTLED, SK_OVERLIMIT) == SK_UNTHROTTLED) { > + sock_hold(sk); > + list_add_tail(&sk->sk_backpressure_node, &sch->backpressure_list); > + } > +} What if socket is closed? You are holding reference but application maybe gone. Or if output is stalled indefinitely?