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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 D82A9C2D0C6 for ; Fri, 27 Dec 2019 08:00:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9234A206F4 for ; Fri, 27 Dec 2019 08:00:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="JokWUboz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726297AbfL0IAw (ORCPT ); Fri, 27 Dec 2019 03:00:52 -0500 Received: from mail-pj1-f67.google.com ([209.85.216.67]:35310 "EHLO mail-pj1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725904AbfL0IAw (ORCPT ); Fri, 27 Dec 2019 03:00:52 -0500 Received: by mail-pj1-f67.google.com with SMTP id s7so4602745pjc.0; Fri, 27 Dec 2019 00:00:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=GqYBn9xekDO9yoyOFcf/nfG+cSXcXjD1udStTq8Obrk=; b=JokWUbozhL0qLM95HCcQ0twlotjea4prxrOvlf9MUOD8VcSiCdXhD4ok95RaGQhLo0 LDCbvjMY8atBcRewyUTUrH30ynMXgQeHmO091NsVKPRkG5nzPq1m6x2EwwSop6giZzT5 GzDVmUJlEKzwOLQyRdXXT8MJWGZFQP/ytYcpGOw6ixsvIthEHIYqwco3EkO2e7N9J9EY bK0RHN8MOKNE+97J6OjdpM4QHuyEfGjF/Kh1LY0uTxS64TxYthQ/64JIbKI/lIq2/hPU nVzwx+Ctbn4TL6CN8KLJcoaRYgRlPyVfA/ox5efQ8GC8yTOJnIaodyU0N5mtnaMB/FxW Z2KQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=GqYBn9xekDO9yoyOFcf/nfG+cSXcXjD1udStTq8Obrk=; b=ShrBjZGUJo3ZUc2UZoyO8TPXyIFFjYO2rPgpCK8WXsL7Z//RpefG7CTXiWCiNuYcD+ T53xtyXzwtic3I1OXXIpURCROPj/Dhce3hxwHdzrnKuZModDSL2ibEFe+EnJtir+82c+ jxvupgphTD5VXJnOHBgwgX4O/xEiohgb9Z4uVMzMdEnyvb7VPGRyYlU7CYr0GVlmH+vW RLOB5gDLg15cwNX0PcduHSfs78ZWFI+Je18tjTkruRSuyNRXPMPy0pyZyylCwAIct6VE Pb4jqbsRenZ3dnLPnXOSZZ71oM/99qTXfMtMcoTZ77JOwq4ShTJWFQ5UY+h+njW3WzXS CJGw== X-Gm-Message-State: APjAAAVJabW4QS3vwqGzTTfXOKYr31nkcu0QLo4yCGSJjgk21FR2k3UY Hbg2kiMYPQK9vNM8I5xRx0VLoq3n+vs= X-Google-Smtp-Source: APXvYqzebkSBQ/WOOG2liWh+Ewqfl2i5nReiRbaBdIf9/Dl7hCmyD+4yoM4TbuPkFOsywf6Ljpcj5Q== X-Received: by 2002:a17:902:728b:: with SMTP id d11mr38277528pll.49.1577433651227; Fri, 27 Dec 2019 00:00:51 -0800 (PST) Received: from CV0038107N9.nsn-intra.net ([2408:84e4:530:1c98:9c33:86ea:e685:846b]) by smtp.gmail.com with ESMTPSA id g22sm36235320pgk.85.2019.12.27.00.00.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 27 Dec 2019 00:00:50 -0800 (PST) From: Kevin Kou To: linux-sctp@vger.kernel.org, netdev@vger.kernel.org Cc: nhorman@tuxdriver.com, marcelo.leitner@gmail.com, davem@davemloft.net, qdkevin.kou@gmail.com Subject: [PATCHv2 net-next] sctp: move trace_sctp_probe_path into sctp_outq_sack Date: Fri, 27 Dec 2019 08:00:34 +0000 Message-Id: <20191227080034.1323-1-qdkevin.kou@gmail.com> X-Mailer: git-send-email 2.23.0.windows.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The original patch bringed in the "SCTP ACK tracking trace event" feature was committed at Dec.20, 2017, it replaced jprobe usage with trace events, and bringed in two trace events, one is TRACE_EVENT(sctp_probe), another one is TRACE_EVENT(sctp_probe_path). The original patch intended to trigger the trace_sctp_probe_path in TRACE_EVENT(sctp_probe) as below code, +TRACE_EVENT(sctp_probe, + + TP_PROTO(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + struct sctp_chunk *chunk), + + TP_ARGS(ep, asoc, chunk), + + TP_STRUCT__entry( + __field(__u64, asoc) + __field(__u32, mark) + __field(__u16, bind_port) + __field(__u16, peer_port) + __field(__u32, pathmtu) + __field(__u32, rwnd) + __field(__u16, unack_data) + ), + + TP_fast_assign( + struct sk_buff *skb = chunk->skb; + + __entry->asoc = (unsigned long)asoc; + __entry->mark = skb->mark; + __entry->bind_port = ep->base.bind_addr.port; + __entry->peer_port = asoc->peer.port; + __entry->pathmtu = asoc->pathmtu; + __entry->rwnd = asoc->peer.rwnd; + __entry->unack_data = asoc->unack_data; + + if (trace_sctp_probe_path_enabled()) { + struct sctp_transport *sp; + + list_for_each_entry(sp, &asoc->peer.transport_addr_list, + transports) { + trace_sctp_probe_path(sp, asoc); + } + } + ), But I found it did not work when I did testing, and trace_sctp_probe_path had no output, I finally found that there is trace buffer lock operation(trace_event_buffer_reserve) in include/trace/trace_events.h: static notrace void \ trace_event_raw_event_##call(void *__data, proto) \ { \ struct trace_event_file *trace_file = __data; \ struct trace_event_data_offsets_##call __maybe_unused __data_offsets;\ struct trace_event_buffer fbuffer; \ struct trace_event_raw_##call *entry; \ int __data_size; \ \ if (trace_trigger_soft_disabled(trace_file)) \ return; \ \ __data_size = trace_event_get_offsets_##call(&__data_offsets, args); \ \ entry = trace_event_buffer_reserve(&fbuffer, trace_file, \ sizeof(*entry) + __data_size); \ \ if (!entry) \ return; \ \ tstruct \ \ { assign; } \ \ trace_event_buffer_commit(&fbuffer); \ } The reason caused no output of trace_sctp_probe_path is that trace_sctp_probe_path written in TP_fast_assign part of TRACE_EVENT(sctp_probe), and it will be placed( { assign; } ) after the trace_event_buffer_reserve() when compiler expands Macro, entry = trace_event_buffer_reserve(&fbuffer, trace_file, \ sizeof(*entry) + __data_size); \ \ if (!entry) \ return; \ \ tstruct \ \ { assign; } \ so trace_sctp_probe_path finally can not acquire trace_event_buffer and return no output, that is to say the nest of tracepoint entry function is not allowed. The function call flow is: trace_sctp_probe() -> trace_event_raw_event_sctp_probe() -> lock buffer -> trace_sctp_probe_path() -> trace_event_raw_event_sctp_probe_path() --nested -> buffer has been locked and return no output. This patch is to remove trace_sctp_probe_path from the TP_fast_assign part of TRACE_EVENT(sctp_probe) to avoid the nest of entry function, and trigger sctp_probe_path_trace in sctp_outq_sack. After this patch, you can enable both events individually, # cd /sys/kernel/debug/tracing # echo 1 > events/sctp/sctp_probe/enable # echo 1 > events/sctp/sctp_probe_path/enable Or, you can enable all the events under sctp. # echo 1 > events/sctp/enable v1->v2: -add trace_sctp_probe_path_enabled check to avoid traversing the transport list when the tracepoint is disabled as Marcelo's suggestion. Signed-off-by: Kevin Kou --- include/trace/events/sctp.h | 9 --------- net/sctp/outqueue.c | 7 +++++++ 2 files changed, 7 insertions(+), 9 deletions(-) diff --git a/include/trace/events/sctp.h b/include/trace/events/sctp.h index 7475c7b..d4aac34 100644 --- a/include/trace/events/sctp.h +++ b/include/trace/events/sctp.h @@ -75,15 +75,6 @@ __entry->pathmtu = asoc->pathmtu; __entry->rwnd = asoc->peer.rwnd; __entry->unack_data = asoc->unack_data; - - if (trace_sctp_probe_path_enabled()) { - struct sctp_transport *sp; - - list_for_each_entry(sp, &asoc->peer.transport_addr_list, - transports) { - trace_sctp_probe_path(sp, asoc); - } - } ), TP_printk("asoc=%#llx mark=%#x bind_port=%d peer_port=%d pathmtu=%d " diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c index 0dab62b..83ddcfe 100644 --- a/net/sctp/outqueue.c +++ b/net/sctp/outqueue.c @@ -36,6 +36,7 @@ #include #include #include +#include /* Declare internal functions here. */ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); @@ -1238,6 +1239,12 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) /* Grab the association's destination address list. */ transport_list = &asoc->peer.transport_addr_list; + /* SCTP path tracepoint for congestion control debugging. */ + if (trace_sctp_probe_path_enabled()) { + list_for_each_entry(transport, transport_list, transports) + trace_sctp_probe_path(transport, asoc); + } + sack_ctsn = ntohl(sack->cum_tsn_ack); gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); asoc->stats.gapcnt += gap_ack_blocks; -- 1.8.3.1