From patchwork Thu Mar 2 17:17:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 63503 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7300:7b8e:b0:9f:8c76:fea4 with SMTP id j14csp5848172dyk; Thu, 2 Mar 2023 09:19:22 -0800 (PST) X-Google-Smtp-Source: AK7set/F9TT33ciDBoJ0idrbDmB1EveAHR7Zxe8docSNwaoOpITU2fpQesUk87csTgerz2FvE5uC X-Received: by 2002:a17:90a:1917:b0:237:659a:a453 with SMTP id 23-20020a17090a191700b00237659aa453mr12413368pjg.16.1677777562069; Thu, 02 Mar 2023 09:19:22 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677777562; cv=none; d=google.com; s=arc-20160816; b=0jDyF0/io8CjKw6Go7CMmI28Px2UuBtWF5yTyqmb7oExITiCm6lVao8OvZzx5qVBQ+ uQjDO7tsrZSlPmaZrW8Ru76JrKabKtyqyLrMZ92pTs24B6S7Yz9+u0kHZadbd2rm0Tg2 rFaa2pgbMw8wO6rK0OSOlFKEKy0pzUoxYLMzLXm9n77w2b2z3HfdMlBRMUaQAZOj2Zqf HFmz/RYFkO+OiCyPKpc4gqXRi4mmX4UB01FfYwbRPHL2p1S4KCLCgzmVg3VFLlTnQTtG 5NhO0Mb7FaqeGa4rv2UuXvjw+2CW0SoFR8/e0iCpIlBJteq4X7DUOrW7udxjr0tBl3ea emeQ== 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 :references:in-reply-to:message-id:date:subject:cc:to:from; bh=dFwyX5fCRCzWJmR23HYHFZHQHmrn3rL22R9ZNcUhtkU=; b=U5vivvGMDj+wKFjVBpHPYfFpzLgrABBmRAN0YSyzrtzAiJdbyJyvMEs8eGAvGtouiG rkZat8bDpuXXyNTpoQWAe3SG+uuaFWsoNGvnTeNCd/oISegmRWygYpmI06fxtoxUnuaE K5sxl3g1qglXr0GwowZi8rOSa/aKIR0/6c+07XYVK4yxQKjsEA/Xk1iMTxUM2hLOEglR w22b/LfXswNmluW+TOQRx3fvLGDOkcqCI+6lKJCUJJnP8fSTOAldoLa6ZPLsI7yD7688 Qrlwoupuvlnl0FPyl5C4u+OSTZ1chHwMxLmQFHn1A9dPzkQ1Mr9UQKhRz+zHDvnsR9Kz Aa7Q== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id t22-20020a17090ad51600b00233f0f06b4asi100137pju.52.2023.03.02.09.19.08; Thu, 02 Mar 2023 09:19:22 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229623AbjCBRSG (ORCPT + 99 others); Thu, 2 Mar 2023 12:18:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55088 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229547AbjCBRSD (ORCPT ); Thu, 2 Mar 2023 12:18:03 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 64C1E61A4; Thu, 2 Mar 2023 09:18:02 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 61C942F4; Thu, 2 Mar 2023 09:18:45 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 41E473F67D; Thu, 2 Mar 2023 09:18:01 -0800 (PST) From: Mark Rutland To: linux-kernel@vger.kernel.org Cc: linux-trace-kernel@vger.kernel.org, mark.rutland@arm.com, mhiramat@kernel.org, rostedt@goodmis.org, zanussi@kernel.org Subject: [PATCH 1/2] tracing/hist: simplify contains_operator() Date: Thu, 2 Mar 2023 17:17:54 +0000 Message-Id: <20230302171755.1821653-2-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230302171755.1821653-1-mark.rutland@arm.com> References: <20230302171755.1821653-1-mark.rutland@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_NONE 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-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759277284892145765?= X-GMAIL-MSGID: =?utf-8?q?1759277284892145765?= In a subsequent patch we'll add additional operators for histogram expressions. In preparation for adding additional operators, this patch refactors contains_operator() to consider each operator within a precedence group independently by using the 'sep' pointer as the current rightmost operator, and removing the separate op pointers. Within each precedence group, this allows operators to be checked independently with a consistent pattern: op = strrchr(str, $OP_CHAR); if (op > *sep) { *sep = op; field_op = $FIELD_OP_TYPE; } This makes it easy to add new operators of the same precedence without needing to check multiple pointers, and without needing a final switch statement to recover the relevant pointer. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Masami Hiramatsu Cc: Steven Rostedt (Google) Cc: Tom Zanussi Cc: linux-trace-kernel@vger.kernel.org --- kernel/trace/trace_events_hist.c | 80 ++++++++++++-------------------- 1 file changed, 30 insertions(+), 50 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 10d36f751fcd..a308da2cde2f 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1813,13 +1813,15 @@ static char *expr_str(struct hist_field *field, unsigned int level) static int contains_operator(char *str, char **sep) { enum field_op_id field_op = FIELD_OP_NONE; - char *minus_op, *plus_op, *div_op, *mult_op; + char *op; + *sep = NULL; /* - * Report the last occurrence of the operators first, so that the - * expression is evaluated left to right. This is important since - * subtraction and division are not associative. + * For operators of the same precedence report the last occurrence of + * the operators first, so that the expression is evaluated left to + * right. This is important since subtraction and division are not + * associative. * * e.g * 64/8/4/2 is 1, i.e 64/8/4/2 = ((64/8)/4)/2 @@ -1830,68 +1832,46 @@ static int contains_operator(char *str, char **sep) * First, find lower precedence addition and subtraction * since the expression will be evaluated recursively. */ - minus_op = strrchr(str, '-'); - if (minus_op) { + op = strrchr(str, '-'); + if (op > *sep) { + *sep = op; + /* * Unary minus is not supported in sub-expressions. If * present, it is always the next root operator. */ - if (minus_op == str) { - field_op = FIELD_OP_UNARY_MINUS; - goto out; - } + if (op == str) + return FIELD_OP_UNARY_MINUS; field_op = FIELD_OP_MINUS; } - plus_op = strrchr(str, '+'); - if (plus_op || minus_op) { - /* - * For operators of the same precedence use to rightmost as the - * root, so that the expression is evaluated left to right. - */ - if (plus_op > minus_op) - field_op = FIELD_OP_PLUS; - goto out; + op = strrchr(str, '+'); + if (op > *sep) { + *sep = op; + field_op = FIELD_OP_PLUS; } /* - * Multiplication and division have higher precedence than addition and - * subtraction. + * If we've found a low-precedence operator, we're done. */ - div_op = strrchr(str, '/'); - if (div_op) - field_op = FIELD_OP_DIV; + if (*sep) + return field_op; - mult_op = strrchr(str, '*'); /* - * For operators of the same precedence use to rightmost as the - * root, so that the expression is evaluated left to right. + * Second, consider the higher precedence multiplication and division + * operators. */ - if (mult_op > div_op) - field_op = FIELD_OP_MULT; + op = strrchr(str, '/'); + if (op > *sep) { + *sep = op; + field_op = FIELD_OP_DIV; + } -out: - if (sep) { - switch (field_op) { - case FIELD_OP_UNARY_MINUS: - case FIELD_OP_MINUS: - *sep = minus_op; - break; - case FIELD_OP_PLUS: - *sep = plus_op; - break; - case FIELD_OP_DIV: - *sep = div_op; - break; - case FIELD_OP_MULT: - *sep = mult_op; - break; - case FIELD_OP_NONE: - default: - *sep = NULL; - break; - } + op = strrchr(str, '*'); + if (op > *sep) { + *sep = op; + field_op = FIELD_OP_MULT; } return field_op;