From patchwork Sat Dec 9 22:52:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 176255 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:bcd1:0:b0:403:3b70:6f57 with SMTP id r17csp6269352vqy; Sat, 9 Dec 2023 14:52:35 -0800 (PST) X-Google-Smtp-Source: AGHT+IGvIEqhkEwTSmak0SVrUAZRb8dJi8JF3OizJ8/fMlOc7CxGqvUPnRD1de/Jhkc5UOOtjK8I X-Received: by 2002:a05:6a00:3992:b0:6ce:2731:e862 with SMTP id fi18-20020a056a00399200b006ce2731e862mr2462964pfb.41.1702162355081; Sat, 09 Dec 2023 14:52:35 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1702162355; cv=none; d=google.com; s=arc-20160816; b=GZiCK0Xg+GdqCTUsBpN6vNCe3U/qGBPrULcIXTZs2Ec+EytnnFmcOYEgqmrh1juvqi 1qhZu1D23qTz6+ulL8ySk7ftr6k1g0IZPU9u8dEo4flA7McgRc8rrhTULULN3Cvnt0ph ZCw79BMa2fRhGsyKOW6Wm6ugke78gc9I33LfZsbJfI1uyZD816m/FzDioDF3a+HQYgsj hhcF8aI+rTkavLRzo3qwyQvnUPw8fMiMPTco1wMn+iWk7CjA9Xaz8J3FvGogaBA6Iicl G5WHrpcxsjGAFkDsRqZCWIIOfZyf/OZ9rrIMmfc4eohXyJtRxpNzg0/yNGPKe9QFdvcB pRIw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:subject:cc:to:from:date; bh=fcCTAntI6h+R5mJVMab4pe+VUn2l3TM+nT9wwhI9dR0=; fh=R8JZsVKDlS7lXIAvTNV55bsjlDBI0i4sqiOYXO4tZQA=; b=T0m2vRKColcSmqFgaFFpL0/Dy4dtm7Tf4mI0Dolhd+6+8VQNux3PXdxm2eryVrXNnv x9Ul6Y+z4b9FEEl1gsGDNjlf7eJia2MUCDWxYljMcumcWZx5N8DtJU7tDh11g4cmpmjQ 3X76R/65MMdvsAb6v+ZYQt6Mk/a0gloxTtrZYQek9Dp9WhYj1Zkr6U3xazMCdFUkFdyS b198B7gWmuA1ndPNofB+x9q0YjAOAtoytAtA0MiRVwR35ovSwnoPD7wQujNRIZ9lLPzu 3VyYBKBG0cNG+UiDhxPPdIEEVeV6abcf49C6j0I2Zwo+YGYK/pVz4JZU5h9T4fymToxN Uppg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from snail.vger.email (snail.vger.email. [23.128.96.37]) by mx.google.com with ESMTPS id j18-20020a632312000000b005c6604d8a80si3632821pgj.121.2023.12.09.14.52.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 09 Dec 2023 14:52:35 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by snail.vger.email (Postfix) with ESMTP id D14F480657CC; Sat, 9 Dec 2023 14:51:58 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at snail.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229509AbjLIWvm (ORCPT + 99 others); Sat, 9 Dec 2023 17:51:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231344AbjLIWvl (ORCPT ); Sat, 9 Dec 2023 17:51:41 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0555712E for ; Sat, 9 Dec 2023 14:51:46 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0731FC433C9; Sat, 9 Dec 2023 22:51:44 +0000 (UTC) Date: Sat, 9 Dec 2023 17:52:20 -0500 From: Steven Rostedt To: LKML , Linux Trace Kernel Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers Subject: [PATCH] trace_seq: Increase the buffer size to almost two pages Message-ID: <20231209175220.19867af4@gandalf.local.home> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Sat, 09 Dec 2023 14:51:59 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1784846593385882452 X-GMAIL-MSGID: 1784846593385882452 From: "Steven Rostedt (Google)" Now that trace_marker can hold more than 1KB string, and can write as much as the ring buffer can hold, the trace_seq is not big enough to hold writes: ~# a="1234567890" ~# cnt=4080 ~# s="" ~# while [ $cnt -gt 10 ]; do ~# s="${s}${a}" ~# cnt=$((cnt-10)) ~# done ~# echo $s > trace_marker ~# cat trace # tracer: nop # # entries-in-buffer/entries-written: 2/2 #P:8 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | <...>-860 [002] ..... 105.543465: tracing_mark_write[LINE TOO BIG] <...>-860 [002] ..... 105.543496: tracing_mark_write: 789012345678901234567890 By increasing the trace_seq buffer to almost two pages, it can now print out the first line. This also subtracts the rest of the trace_seq fields from the buffer, so that the entire trace_seq is now PAGE_SIZE aligned. Signed-off-by: Steven Rostedt (Google) Reviewed-by: Masami Hiramatsu (Google) --- include/linux/trace_seq.h | 9 ++++++--- kernel/trace/trace.c | 6 +++--- kernel/trace/trace_seq.c | 3 --- 3 files changed, 9 insertions(+), 9 deletions(-) diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 3691e0e76a1a..9ec229dfddaa 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -8,11 +8,14 @@ /* * Trace sequences are used to allow a function to call several other functions - * to create a string of data to use (up to a max of PAGE_SIZE). + * to create a string of data to use. */ +#define TRACE_SEQ_BUFFER_SIZE (PAGE_SIZE * 2 - \ + (sizeof(struct seq_buf) + sizeof(size_t) + sizeof(int))) + struct trace_seq { - char buffer[PAGE_SIZE]; + char buffer[TRACE_SEQ_BUFFER_SIZE]; struct seq_buf seq; size_t readpos; int full; @@ -21,7 +24,7 @@ struct trace_seq { static inline void trace_seq_init(struct trace_seq *s) { - seq_buf_init(&s->seq, s->buffer, PAGE_SIZE); + seq_buf_init(&s->seq, s->buffer, TRACE_SEQ_BUFFER_SIZE); s->full = 0; s->readpos = 0; } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 83393c65ec71..da837119a446 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3753,7 +3753,7 @@ static bool trace_safe_str(struct trace_iterator *iter, const char *str, /* OK if part of the temp seq buffer */ if ((addr >= (unsigned long)iter->tmp_seq.buffer) && - (addr < (unsigned long)iter->tmp_seq.buffer + PAGE_SIZE)) + (addr < (unsigned long)iter->tmp_seq.buffer + TRACE_SEQ_BUFFER_SIZE)) return true; /* Core rodata can not be freed */ @@ -6926,8 +6926,8 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, goto out; } - if (cnt >= PAGE_SIZE) - cnt = PAGE_SIZE - 1; + if (cnt >= TRACE_SEQ_BUFFER_SIZE) + cnt = TRACE_SEQ_BUFFER_SIZE - 1; /* reset all but tr, trace, and overruns */ trace_iterator_reset(iter); diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 7be97229ddf8..c158d65a8a88 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -13,9 +13,6 @@ * trace_seq_init() more than once to reset the trace_seq to start * from scratch. * - * The buffer size is currently PAGE_SIZE, although it may become dynamic - * in the future. - * * A write to the buffer will either succeed or fail. That is, unlike * sprintf() there will not be a partial write (well it may write into * the buffer but it wont update the pointers). This allows users to