From patchwork Wed Sep 15 19:52:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kalesh Singh X-Patchwork-Id: 12497297 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B469FC433EF for ; Wed, 15 Sep 2021 19:53:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7FDCB60FED for ; Wed, 15 Sep 2021 19:53:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231719AbhIOTzE (ORCPT ); Wed, 15 Sep 2021 15:55:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229732AbhIOTzD (ORCPT ); Wed, 15 Sep 2021 15:55:03 -0400 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79CB4C061764 for ; Wed, 15 Sep 2021 12:53:44 -0700 (PDT) Received: by mail-qv1-xf4a.google.com with SMTP id v1-20020a0cc1c1000000b0037c671dbf1cso7895988qvh.12 for ; Wed, 15 Sep 2021 12:53:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=sVrJdEErDsLvRaIvb4CeOJb0g1GXWTlBERxtwXGY8HE=; b=EF/Zdx1yS38c5HY21otyrQ+dN9YognFFRBeWIi6ndcOEAxCRrbPgOWTYlC9UvR5ZKI uTxWvIc06UJtndo6LfQx0+zkShzvsz0COyD28WDmP9SMRbqS6ALTuKOhIH2763U5IWpo L+l1st2odVLiVjJ/365RyRkHcqbq9awUqgaDOdASI3uDhFvOFjX/Q8/FL3ntZ2V6q0Cf W/rXCCABLtyPabSFpHhNlxJMPtYHR5UuspGeXCa/wyEzwnduwXizgnaIPABNpbIuy0+N C0B066hxKq9pQIL7cfH1EnOpzWTbwyAPZ7FWMqcsrIVyCw86xpklBSc/t/V+HKSCJdht vO5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=sVrJdEErDsLvRaIvb4CeOJb0g1GXWTlBERxtwXGY8HE=; b=k8kqAUIk2UJPmW/SNijelCynJppTBheVjq45gfRkVxgXK4KMso105QKs0DT7/Mo2Sp SjaaKQuyg7Lxq+1OrIvBFGJvA/dJLi9SaeqJQHqoT1JkUi+tzG4CtoyE9ohFfVLka3JQ fvVqFnkOqGCLGPdiYGys5W2wsXnOqMlZg03Uet6+aOsOcLy/Ga0cPRC6kci+3n7lDezP kvGLOz8oGf6lTnHyOL3OrYrd5IDovIvfjCQTZHvhvf45OpJ7fSEGgHOEh56W2isKykxa lsWakptxrxoHm2/suqUU6SwkRHzxROmgtn05aXvzVwki3ojH7YPqIlDDzsyw5VhmJaWz X6Og== X-Gm-Message-State: AOAM533A0H5OlhAt/E+iGYG2FzYLeuaR38t2e2XeJFPQ+WOrSndEybcw 12ugEsvKiW/4pXyb8wvg6xQo1S3Cd7yhHQRtAw== X-Google-Smtp-Source: ABdhPJzFgzXL254C6TJScd4rbVqalNmOtOpQrcr3F0qHUJHI4lsGkBvLdvyBlcXeL4qfNFhEkbRsblZgj+cg57lgyg== X-Received: from kaleshsingh.c.googlers.com ([fda3:e722:ac3:cc00:14:4d90:c0a8:2145]) (user=kaleshsingh job=sendgmr) by 2002:a0c:8c81:: with SMTP id p1mr1771257qvb.7.1631735623651; Wed, 15 Sep 2021 12:53:43 -0700 (PDT) Date: Wed, 15 Sep 2021 19:52:45 +0000 In-Reply-To: <20210915195306.612966-1-kaleshsingh@google.com> Message-Id: <20210915195306.612966-2-kaleshsingh@google.com> Mime-Version: 1.0 References: <20210915195306.612966-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.33.0.309.g3052b89438-goog Subject: [PATCH 1/5] tracing: Add support for creating hist trigger variables from literal From: Kalesh Singh Cc: surenb@google.com, hridya@google.com, namhyung@kernel.org, Kalesh Singh , Jonathan Corbet , Steven Rostedt , Ingo Molnar , Shuah Khan , Tom Zanussi , Masami Hiramatsu , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Currently hist trigger expressions don't support the use of numeric literals: e.g. echo 'hist:keys=common_pid:x=$y-1234' --> is not valid expression syntax Having the ability to use numeric constants in hist triggers supports a wider range of expressions for creating variables. Add support for creating trace event histogram variables from numeric literals. e.g. echo 'hist:keys=common_pid:x=1234,y=size-1024' >> event/trigger A negative numeric constant is created, using unary minus operator (parentheses are required). e.g. echo 'hist:keys=common_pid:z=-(2)' >> event/trigger Signed-off-by: Kalesh Singh --- kernel/trace/trace_events_hist.c | 80 +++++++++++++++++++++++++++++++- 1 file changed, 79 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index a6061a69aa84..2802b211ccf3 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -66,7 +66,9 @@ C(EMPTY_SORT_FIELD, "Empty sort field"), \ C(TOO_MANY_SORT_FIELDS, "Too many sort fields (Max = 2)"), \ C(INVALID_SORT_FIELD, "Sort field must be a key or a val"), \ - C(INVALID_STR_OPERAND, "String type can not be an operand in expression"), + C(INVALID_STR_OPERAND, "String type can not be an operand in expression"), \ + C(TOO_MANY_CONSTS, "Too many constants defined"), \ + C(EXPECT_NUMBER, "Expecting numeric literal"), #undef C #define C(a, b) HIST_ERR_##a @@ -89,6 +91,8 @@ typedef u64 (*hist_field_fn_t) (struct hist_field *field, #define HIST_FIELD_OPERANDS_MAX 2 #define HIST_FIELDS_MAX (TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX) #define HIST_ACTIONS_MAX 8 +#define HIST_CONST_MAX 4 +#define HIST_CONST_DIGITS_MAX 21 enum field_op_id { FIELD_OP_NONE, @@ -152,6 +156,9 @@ struct hist_field { bool read_once; unsigned int var_str_idx; + + /* Numeric literals are represented as u64 */ + u64 constant; }; static u64 hist_field_none(struct hist_field *field, @@ -163,6 +170,15 @@ static u64 hist_field_none(struct hist_field *field, return 0; } +static u64 hist_field_const(struct hist_field *field, + struct tracing_map_elt *elt, + struct trace_buffer *buffer, + struct ring_buffer_event *rbe, + void *event) +{ + return field->constant; +} + static u64 hist_field_counter(struct hist_field *field, struct tracing_map_elt *elt, struct trace_buffer *buffer, @@ -341,6 +357,7 @@ enum hist_field_flags { HIST_FIELD_FL_CPU = 1 << 15, HIST_FIELD_FL_ALIAS = 1 << 16, HIST_FIELD_FL_BUCKET = 1 << 17, + HIST_FIELD_FL_CONST = 1 << 18, }; struct var_defs { @@ -410,6 +427,7 @@ struct hist_trigger_data { struct field_var *save_vars[SYNTH_FIELDS_MAX]; unsigned int n_save_vars; unsigned int n_save_var_str; + unsigned int n_constants; }; struct action_data; @@ -1516,6 +1534,12 @@ static void expr_field_str(struct hist_field *field, char *expr) { if (field->flags & HIST_FIELD_FL_VAR_REF) strcat(expr, "$"); + else if (field->flags & HIST_FIELD_FL_CONST) { + char str[HIST_CONST_DIGITS_MAX]; + + snprintf(str, HIST_CONST_DIGITS_MAX, "%llu", field->constant); + strcat(expr, str); + } strcat(expr, hist_field_name(field, 0)); @@ -1689,6 +1713,15 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, goto out; } + if (flags & HIST_FIELD_FL_CONST) { + hist_field->fn = hist_field_const; + hist_field->size = sizeof(u64); + hist_field->type = kstrdup("u64", GFP_KERNEL); + if (!hist_field->type) + goto free; + goto out; + } + if (flags & HIST_FIELD_FL_STACKTRACE) { hist_field->fn = hist_field_none; goto out; @@ -2090,6 +2123,35 @@ static struct hist_field *create_alias(struct hist_trigger_data *hist_data, return alias; } +static struct hist_field *parse_const(struct hist_trigger_data *hist_data, + char *str, char *var_name, + unsigned long *flags) +{ + struct trace_array *tr = hist_data->event_file->tr; + struct hist_field *field = NULL; + u64 constant; + + if (hist_data->n_constants >= HIST_CONST_MAX) { + hist_err(tr, HIST_ERR_TOO_MANY_CONSTS, errpos(str)); + return NULL; + } + + if (kstrtoull(str, 0, &constant)) { + hist_err(tr, HIST_ERR_EXPECT_NUMBER, errpos(str)); + return NULL; + } + + *flags |= HIST_FIELD_FL_CONST; + field = create_hist_field(hist_data, NULL, *flags, var_name); + if (!field) + return NULL; + + field->constant = constant; + hist_data->n_constants++; + + return field; +} + static struct hist_field *parse_atom(struct hist_trigger_data *hist_data, struct trace_event_file *file, char *str, unsigned long *flags, char *var_name) @@ -2100,6 +2162,15 @@ static struct hist_field *parse_atom(struct hist_trigger_data *hist_data, unsigned long buckets = 0; int ret = 0; + if (isdigit(str[0])) { + hist_field = parse_const(hist_data, str, var_name, flags); + if (!hist_field) { + ret = -EINVAL; + goto out; + } + return hist_field; + } + s = strchr(str, '.'); if (s) { s = strchr(++s, '.'); @@ -4950,6 +5021,8 @@ static void hist_field_debug_show_flags(struct seq_file *m, if (flags & HIST_FIELD_FL_ALIAS) seq_puts(m, " HIST_FIELD_FL_ALIAS\n"); + else if (flags & HIST_FIELD_FL_CONST) + seq_puts(m, " HIST_FIELD_FL_CONST\n"); } static int hist_field_debug_show(struct seq_file *m, @@ -4971,6 +5044,9 @@ static int hist_field_debug_show(struct seq_file *m, field->var.idx); } + if (field->flags & HIST_FIELD_FL_CONST) + seq_printf(m, " constant: %llu\n", field->constant); + if (field->flags & HIST_FIELD_FL_ALIAS) seq_printf(m, " var_ref_idx (into hist_data->var_refs[]): %u\n", field->var_ref_idx); @@ -5213,6 +5289,8 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field) if (hist_field->flags & HIST_FIELD_FL_CPU) seq_puts(m, "common_cpu"); + else if (hist_field->flags & HIST_FIELD_FL_CONST) + seq_printf(m, "%llu", hist_field->constant); else if (field_name) { if (hist_field->flags & HIST_FIELD_FL_VAR_REF || hist_field->flags & HIST_FIELD_FL_ALIAS)