From nobody Fri Sep 12 01:05:09 2025 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 EC225EB64DD for ; Wed, 9 Aug 2023 13:17:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232824AbjHINRM (ORCPT ); Wed, 9 Aug 2023 09:17:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229560AbjHINRK (ORCPT ); Wed, 9 Aug 2023 09:17:10 -0400 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B945128 for ; Wed, 9 Aug 2023 06:17:10 -0700 (PDT) Received: from pps.filterd (m0279863.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 379CH6jf003576; Wed, 9 Aug 2023 13:17:01 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=qcppdkim1; bh=wqiKosW8sF+2lO6oeFYvAFaiESETnfkgoeH2ctKPazA=; b=GVyMCY3DVRLmWcqV9THB8vNZWWTJEhfNJj+3cftvXKzR2toh4QioDIYJZ/TXCeVDWk39 Z/Gb7ujyn+0HgHu75yLx0ArUlSzFRN7HNP8wqVG4fbwstNzGu1OY+p09GaDH+TYfKm8u rxvXELiPmbquBnWCdAUZ+o60R6Uhkk6U+8Y98wfreKqHZ2yWmpYEJVSrvRFKP8ICwxMY tX9B2LyVBEHd+uOExjzaz+ECGDr98CPKcZ1BtMhNsSzUpdeHOFDB9GDNtXlC45E8LMCa 43g4j9nYrDD/31joLvvSIlIMC1n0wYFlV6zimp5mznPJbjirL2AVnYsiXmeBXyESPHEq hg== Received: from nalasppmta03.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3sc0051epq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 09 Aug 2023 13:17:01 +0000 Received: from nalasex01c.na.qualcomm.com (nalasex01c.na.qualcomm.com [10.47.97.35]) by NALASPPMTA03.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 379DH0s5025420 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 9 Aug 2023 13:17:00 GMT Received: from hyd-lablnx450.qualcomm.com (10.80.80.8) by nalasex01c.na.qualcomm.com (10.47.97.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.30; Wed, 9 Aug 2023 06:16:58 -0700 From: Bibek Kumar Patro To: CC: , , , , Bibek Kumar Patro Subject: [PATCH v2] cma: introduce CMA_ALLOC_DEBUG config Date: Wed, 9 Aug 2023 18:46:40 +0530 Message-ID: <20230809131640.18791-1-quic_bibekkum@quicinc.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01c.na.qualcomm.com (10.47.97.35) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: MgpH7odurn7fcTmOimzhzs8mDBhptik9 X-Proofpoint-GUID: MgpH7odurn7fcTmOimzhzs8mDBhptik9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-08-09_10,2023-08-09_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 spamscore=0 malwarescore=0 priorityscore=1501 lowpriorityscore=0 suspectscore=0 bulkscore=0 mlxscore=0 adultscore=0 phishscore=0 clxscore=1011 mlxlogscore=975 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2306200000 definitions=main-2308090117 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Currently enabling CONFIG_CMA_DEBUG enables DEBUG preprocessor macro. If DEBUG is defined, it's equivalent to a printk with KERN_DEBUG loglevel flooding the dmesg buffer with pr_debug prints from mm/cma driver and from included files as well. This results in excessive amount of CMA logging and also might distract the debug teams with unrelated KERN_DEBUG prints.One of the ways engineers currently tackle this problem is by passing loglevel=3DN though commandline to suppress KERN_DEBUG messages. This approach can sometimes become tiresome due to its repetitive nature. This patch proposes an alternative approach by introducing a simple new config CONFIG_CMA_ALLOC_DEBUG which only shows the cma bit allocation status in case of cma failure and do not enable DEBUG preprocessor macro from CONFIG_CMA_DEBUG avoiding excessive CMA logging from pr_debug. Engineers and tech teams seeking only for bitmap status in case of cma failure can use this simple config instead of worrying about changing the loglevel or trying other similar workarounds. Signed-off-by: Bibek Kumar Patro --- mm/Kconfig | 11 +++++++++++ mm/cma.c | 2 +- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/mm/Kconfig b/mm/Kconfig index 09130434e30d..ad2a20576a65 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -891,12 +891,23 @@ config CMA config CMA_DEBUG bool "CMA debug messages (DEVELOPMENT)" depends on DEBUG_KERNEL && CMA + select CMA_ALLOC_DEBUG help Turns on debug messages in CMA. This produces KERN_DEBUG messages for every CMA call as well as various messages while processing calls such as dma_alloc_from_contiguous(). This option does not affect warning and error messages. +config CMA_ALLOC_DEBUG + bool "CMA bitmap status upon failure" + depends on CMA + help + Turns on bitmap dump in case of cma failures. This prints + current status of CMA bit upon failures and will appear + when cma_alloc() return no_warn argument as false and won't + flood the dmesg buffer with unrelated KERN_DEBUG prints. No + need to explicitly enable this if CMA_DEBUG is enabled. + config CMA_DEBUGFS bool "CMA debugfs interface" depends on CMA && DEBUG_FS diff --git a/mm/cma.c b/mm/cma.c index a4cfe995e11e..0ead392769b3 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -383,7 +383,7 @@ int __init cma_declare_contiguous_nid(phys_addr_t base, return ret; } -#ifdef CONFIG_CMA_DEBUG +#ifdef CONFIG_CMA_ALLOC_DEBUG static void cma_debug_show_areas(struct cma *cma) { unsigned long next_zero_bit, next_set_bit, nr_zero; -- 2.17.1