From patchwork Thu Feb 22 21:14:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 205066 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7300:a81b:b0:108:e6aa:91d0 with SMTP id bq27csp213720dyb; Thu, 22 Feb 2024 13:14:36 -0800 (PST) X-Forwarded-Encrypted: i=3; AJvYcCXEPxonjrN1wn2I4LEz1DtyzLgcgBBvY/6nfrSSPpoIIdhMdWEMSJJUPUjnjzjrUm6bYIEng6iVvN3pK/tHS7omDx6tJg== X-Google-Smtp-Source: AGHT+IF0wEBSraW+hYuBU/lKPCUJxdNTRFrS0G3jQPJSxIumCedzOrD+HjsDaMjei8TEWZsoU10r X-Received: by 2002:a25:6f8a:0:b0:dcb:d0cb:651e with SMTP id k132-20020a256f8a000000b00dcbd0cb651emr381192ybc.28.1708636476057; Thu, 22 Feb 2024 13:14:36 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1708636476; cv=pass; d=google.com; s=arc-20160816; b=WJeC6z2CDiYedMuG2iNKw3MpPHWQtxXUc6vyjy8f1SNxOHh+w5CWaobYgcshlrkC7y 4iyG9UM6H0+Eb1QOpAURjKB/B9mRqN1KhZ28P1YJJQisndtEcoVVBDjgJKJZaJ2tA9dR buwC3Drzg8Z295uOhqTvvLDWl0L7J1MWIimEPLPau4SITFzWtCLvXbMo0FGiypSS7AOp g+beIimOJZPUbnRAUmEjOxH7kch8hr7+CsGmU1eDA8ig3gQWuGFIhuTn+QS2Fr89DlBW fs/uFtUavVqy7Fh9rvV+pHJ8eetd9AM/WRThXKVyEFALsxWaLvIcRFaPX8TsZLsKeDI4 LHVQ== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:list-unsubscribe:list-subscribe:list-id:precedence :references:subject:cc:to:from:date:user-agent:message-id; bh=DhHmbMpaA1k4qN5yLQZTbOyHIppdPNq95Qj4wRPuVYs=; fh=6lU0d7+j2gvP0RlfbRyidxN6N8cP9012O+fDGzz+FVE=; b=sxlRQ3cFshjkdCvuT+jwBhTXn//cekaLH5tsfaTwnKGQjcJD0iYBdxI72IAKmDVT8Q +/nR4Tuqe2aEKKTBgDETg5qjGomvs2wLnoEY1Vx5hznW3U6dJiArPzQqqtwsiACe9izG Dlb0dZmmapA6FcP9YvafYKmdiyAo4qSoUgXmyjk7cjfAkKx7V0WSM3DVbaroD+f4Uxba +tDCGWO1Hbd7UWcTmTvmbRMtl+KfYV/30cb1943pTpVW9tNWxfL9/luyKAvSsTqPrjuc Mps/irZ5OyXHQmtEdiITuh8xEnK1dqB0kf6jMpQvwhynkgVyhu9Esr8bMKnITMrppzgK Yzeg==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; arc=pass (i=1); spf=pass (google.com: domain of linux-kernel+bounces-77377-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) smtp.mailfrom="linux-kernel+bounces-77377-ouuuleilei=gmail.com@vger.kernel.org" Received: from ny.mirrors.kernel.org (ny.mirrors.kernel.org. [147.75.199.223]) by mx.google.com with ESMTPS id l21-20020a05620a0c1500b007874ee5955esi12607311qki.475.2024.02.22.13.14.35 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Feb 2024 13:14:36 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-77377-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223; Authentication-Results: mx.google.com; arc=pass (i=1); spf=pass (google.com: domain of linux-kernel+bounces-77377-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) smtp.mailfrom="linux-kernel+bounces-77377-ouuuleilei=gmail.com@vger.kernel.org" Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ny.mirrors.kernel.org (Postfix) with ESMTPS id D19DF1C2377E for ; Thu, 22 Feb 2024 21:14:35 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C205B13BAF4; Thu, 22 Feb 2024 21:12:53 +0000 (UTC) Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 089F012D1F9; Thu, 22 Feb 2024 21:12:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708636372; cv=none; b=gHZnUNM7uCeJRP18DSFZ3IPImu5A4bFXYUiq1zROh26ec+RcpSLwHGLpPiNsAsWDTTPyy1DIO5CVD7Srk/LAdG78K4kFwD5N1UgODh26kgIaJLh0xw3eNWeD8XDvZDBdylS0W0k9yI6+QFLq/6wrJpma8BPOG4nDbKYhRazqNTc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708636372; c=relaxed/simple; bh=ASKKBEQ/kPwz5mh0vibiuZNuVaq8X/g1jUk/IeZwsxE=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=ak7iD70+I0Mk0DIRHsL0IgGl4vtilJglWGs+jkb4cGpqR3FwEo+6zqefTfqFybrbZzOoXs+2kUML0lpWQYDuk/njfs3gMwJddItdJw6sLzgHUHBf01ZZe1sVBedqSN3U+5DqBDZTlGsmm8uxPIB7Ua1bUkUnNn3RXDLUhm1V7Tw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id B556DC433A6; Thu, 22 Feb 2024 21:12:51 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97) (envelope-from ) id 1rdGOw-00000006hqt-3tgc; Thu, 22 Feb 2024 16:14:42 -0500 Message-ID: <20240222211442.793074999@goodmis.org> User-Agent: quilt/0.67 Date: Thu, 22 Feb 2024 16:14:17 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= , Rodrigo Vivi , Chuck Lever Subject: [PATCH v2 2/4] tracing: Do not calculate strlen() twice for __string() fields References: <20240222211415.255659509@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1791635201421362761 X-GMAIL-MSGID: 1791635201421362761 From: "Steven Rostedt (Google)" The TRACE_EVENT() macro handles dynamic strings by having: TP_PROTO(struct some_struct *s), TP_ARGS(s), TP_STRUCT__entry( __string(my_string, s->string) ), TP_fast_assign( __assign_str(my_string, s->string); ) TP_printk("%s", __get_str(my_string)) There's even some code that may call a function helper to find the s->string value. The problem with the above is that the work to get the s->string is done twice. Once at the __string() and again in the __assign_str(). The length of the string is calculated via a strlen(), not once, but twice. Once during the __string() macro and again in __assign_str(). But the length is actually already recorded in the data location and here's no reason to call strlen() again. Just use the saved length that was saved in the __string() code for the __assign_str() code. Signed-off-by: Steven Rostedt (Google) --- include/trace/stages/stage6_event_callback.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h index b3e2f321e787..c0e5d097324e 100644 --- a/include/trace/stages/stage6_event_callback.h +++ b/include/trace/stages/stage6_event_callback.h @@ -32,8 +32,9 @@ #undef __assign_str #define __assign_str(dst, src) \ - strcpy(__get_str(dst), __data_offsets.dst##_ptr_ ? \ - __data_offsets.dst##_ptr_ : "(null)") + memcpy(__get_str(dst), __data_offsets.dst##_ptr_ ? \ + __data_offsets.dst##_ptr_ : "(null)", \ + __get_dynamic_array_len(dst)) #undef __assign_str_len #define __assign_str_len(dst, src, len) \ @@ -94,8 +95,9 @@ #undef __assign_rel_str #define __assign_rel_str(dst, src) \ - strcpy(__get_rel_str(dst), __data_offsets.dst##_ptr_ ? \ - __data_offsets.dst##_ptr_ : "(null)") + memcpy(__get_rel_str(dst), __data_offsets.dst##_ptr_ ? \ + __data_offsets.dst##_ptr_ : "(null)", \ + __get_rel_dynamic_array_len(dst)) #undef __assign_rel_str_len #define __assign_rel_str_len(dst, src, len) \