From patchwork Tue Sep 24 05:13:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaoguang Wang X-Patchwork-Id: 1166319 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.alibaba.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 46cq9b6jdcz9sPK for ; Tue, 24 Sep 2019 15:14:11 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2409024AbfIXFOL (ORCPT ); Tue, 24 Sep 2019 01:14:11 -0400 Received: from out30-54.freemail.mail.aliyun.com ([115.124.30.54]:49765 "EHLO out30-54.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404357AbfIXFOK (ORCPT ); Tue, 24 Sep 2019 01:14:10 -0400 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R141e4; CH=green; DM=||false|; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04420; MF=xiaoguang.wang@linux.alibaba.com; NM=1; PH=DS; RN=2; SR=0; TI=SMTPD_---0TdH8ZPI_1569302045; Received: from localhost(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0TdH8ZPI_1569302045) by smtp.aliyun-inc.com(127.0.0.1); Tue, 24 Sep 2019 13:14:06 +0800 From: Xiaoguang Wang To: linux-ext4@vger.kernel.org Cc: Xiaoguang Wang Subject: [PATCH 3/3] jbd2: add new tracepoint jbd2_wait_on_credits Date: Tue, 24 Sep 2019 13:13:50 +0800 Message-Id: <20190924051350.1740-3-xiaoguang.wang@linux.alibaba.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20190924051350.1740-1-xiaoguang.wang@linux.alibaba.com> References: <20190924051350.1740-1-xiaoguang.wang@linux.alibaba.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org In current jbd2's implemention, jbd2 won't reclaim journal space unless free journal space is lower than specified threshold, sometimes there'll be many processes blocked on waiting for free journal space, so here also add a tracepoint to trace this delay: Trace info likes below: rm-1609 [012] .... 232.134012: jbd2_wait_on_credits: dev 254,17 latency(us) 30249 rm-1609 [012] .... 232.540123: jbd2_wait_on_credits: dev 254,17 latency(us) 45491 rm-1609 [012] .... 233.074011: jbd2_wait_on_credits: dev 254,17 latency(us) 111308 rm-1609 [012] .... 233.798669: jbd2_wait_on_credits: dev 254,17 latency(us) 54398 rm-1609 [011] .... 234.311211: jbd2_wait_on_credits: dev 254,17 latency(us) 48049 rm-1609 [011] .... 234.917501: jbd2_wait_on_credits: dev 254,17 latency(us) 51491 rm-1609 [011] .... 235.776268: jbd2_wait_on_credits: dev 254,17 latency(us) 51248 Signed-off-by: Xiaoguang Wang --- fs/jbd2/transaction.c | 6 +++++- include/trace/events/jbd2.h | 20 ++++++++++++++++++++ 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index 6757911a4a17..15f613ae32de 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -266,8 +266,12 @@ static int add_transaction_credits(journal_t *journal, int blocks, read_unlock(&journal->j_state_lock); jbd2_might_wait_for_commit(journal); write_lock(&journal->j_state_lock); - if (jbd2_log_space_left(journal) < jbd2_space_needed(journal)) + if (jbd2_log_space_left(journal) < jbd2_space_needed(journal)) { + s64 start_us = ktime_to_us(ktime_get()); __jbd2_log_wait_for_space(journal); + trace_jbd2_wait_on_credits(journal->j_fs_dev->bd_dev, + ktime_to_us(ktime_get()) - start_us); + } write_unlock(&journal->j_state_lock); return 1; } diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h index f2eebd839bf2..108f320ef362 100644 --- a/include/trace/events/jbd2.h +++ b/include/trace/events/jbd2.h @@ -422,6 +422,26 @@ TRACE_EVENT(jbd2_wait_on_transaction_locked, __entry->wait_us) ); +TRACE_EVENT(jbd2_wait_on_credits, + + TP_PROTO(dev_t dev, unsigned long wait_us), + + TP_ARGS(dev, wait_us), + + TP_STRUCT__entry( + __field( dev_t, dev ) + __field(unsigned long, wait_us ) + ), + + TP_fast_assign( + __entry->dev = dev; + __entry->wait_us = wait_us; + ), + + TP_printk("dev %d,%d latency(us) %lu", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->wait_us) +); #endif /* _TRACE_JBD2_H */ /* This part must be outside protection */