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 5294FC001DB for ; Tue, 8 Aug 2023 18:22:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235140AbjHHSWv (ORCPT ); Tue, 8 Aug 2023 14:22:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233894AbjHHSWb (ORCPT ); Tue, 8 Aug 2023 14:22:31 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 181DB7ED4 for ; Tue, 8 Aug 2023 10:33:13 -0700 (PDT) Received: from pps.filterd (m0360083.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 378HSE4S012620; Tue, 8 Aug 2023 17:33:11 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : references : date : in-reply-to : message-id : mime-version : content-type; s=pp1; bh=ce6KrtxW1N1M1KpdmyHfcpXsMxruBSPZBYwCMFJvTy0=; b=myf/rhRl+04/jXK3GAYIxFnSxfWU0sUyxnygeTCfUrXoJzV70jaM8eZfFnUeMMP+cWwW mPYLAhCFmRryJEemxbomsGLEo3Up6+eM9cFPlNY81KHE05zdsRX0OMoYbNLg/lVMyvAZ QMP+Jp4CKqzycOnhwn8zc7o0Ym1VxiAf6vuJPlxETiLwg9IZX7DNuGHoJxZzhumQrNO6 IvGYdtHNySiy2v7XjWG3bCcnZtD9GF75ldat4paQmyhjYkgejGqx18e62lSK22ABLXY1 FbhXmrccponDGJWtaZpH8eG6qdPECBtHXWeqIgNx9VJRvFEMmgwXIdZP6+bzFlcT70R+ vA== Received: from ppma21.wdc07v.mail.ibm.com (5b.69.3da9.ip4.static.sl-reverse.com [169.61.105.91]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3sbt4t03j9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 08 Aug 2023 17:33:10 +0000 Received: from pps.filterd (ppma21.wdc07v.mail.ibm.com [127.0.0.1]) by ppma21.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 378HEefF030353; Tue, 8 Aug 2023 17:33:09 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma21.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3sa1rn8qfs-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 08 Aug 2023 17:33:09 +0000 Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 378HX72n21430984 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 8 Aug 2023 17:33:07 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6AE9120043; Tue, 8 Aug 2023 17:33:07 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4375F20040; Tue, 8 Aug 2023 17:33:07 +0000 (GMT) Received: from tuxmaker.linux.ibm.com (unknown [9.152.85.9]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTPS; Tue, 8 Aug 2023 17:33:07 +0000 (GMT) From: Sven Schnelle To: Steven Rostedt Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] tracing/synthetic: use union instead of casts References: <20230808142148.2652883-1-svens@linux.ibm.com> <20230808132726.08cabfbc@gandalf.local.home> Date: Tue, 08 Aug 2023 19:33:06 +0200 In-Reply-To: <20230808132726.08cabfbc@gandalf.local.home> (Steven Rostedt's message of "Tue, 8 Aug 2023 13:27:26 -0400") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: ZZOva1gYbPQFMS-khdBW-CrOGnVEOmZ_ X-Proofpoint-GUID: ZZOva1gYbPQFMS-khdBW-CrOGnVEOmZ_ 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=2023-08-08_15,2023-08-08_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 spamscore=0 phishscore=0 mlxscore=0 adultscore=0 suspectscore=0 clxscore=1015 malwarescore=0 lowpriorityscore=0 priorityscore=1501 mlxlogscore=899 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2306200000 definitions=main-2308080156 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Steven Rostedt writes: > The "dynamic" I was using wasn't about the fields were dynamic (union), but > because the field the offset/len combo represents is of dynamic size. It's > used all over the trace_events code. > > I would have in include/linux/trace_events.h (right above struct trace_entry): > > /* Used to find the offset and length of dynamic fields in trace events */ > struct trace_dynamic_info { > #ifdef CONFIG_CPU_BIG_ENDIAN > u16 offset; > u16 len; > #else > u16 len; > u16 offset; > #endif > }; > > And then it kernel/trace/trace.h: > > union trace_synthetic_field { > u8 as_u8; > u16 as_u16; > u32 as_u32; > u64 as_u64; > struct trace_dynamic_info as_dynamic; > }; Ok. > I could work on the part of the trace_dynamic_info if you want. Whatever you prefer. Should i update my patch and send it again, or do you want to adjust it? Thanks Sven