Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752462AbdFZWzO (ORCPT ); Mon, 26 Jun 2017 18:55:14 -0400 Received: from mga01.intel.com ([192.55.52.88]:32509 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751953AbdFZWuW (ORCPT ); Mon, 26 Jun 2017 18:50:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,397,1493708400"; d="scan'208";a="119078388" From: Tom Zanussi To: rostedt@goodmis.org Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org, vedang.patel@intel.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, Tom Zanussi Subject: [PATCH 18/32] tracing: Add simple expression support to hist triggers Date: Mon, 26 Jun 2017 17:49:19 -0500 Message-Id: X-Mailer: git-send-email 1.9.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 15995 Lines: 601 Add support for simple addition, subtraction, and unary expressions (-(expr) and expr, where expr = b-a, a+b, a+b+c) to hist triggers, in order to support a minimal set of useful inter-event calculations. These operations are needed for calculating latencies between events (timestamp1-timestamp0) and for combined latencies (latencies over 3 or more events). In the process, factor out some common code from key and value parsing. Signed-off-by: Tom Zanussi --- kernel/trace/trace_events_hist.c | 457 +++++++++++++++++++++++++++++++++------ 1 file changed, 390 insertions(+), 67 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index fa8f607..92a9d89 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -32,6 +32,13 @@ typedef u64 (*hist_field_fn_t) (struct hist_field *field, void *event, #define HIST_FIELD_OPERANDS_MAX 2 #define HIST_FIELDS_MAX (TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX) +enum field_op_id { + FIELD_OP_NONE, + FIELD_OP_PLUS, + FIELD_OP_MINUS, + FIELD_OP_UNARY_MINUS, +}; + struct hist_var { char *name; struct hist_trigger_data *hist_data; @@ -48,6 +55,8 @@ struct hist_field { struct hist_field *operands[HIST_FIELD_OPERANDS_MAX]; struct hist_trigger_data *hist_data; struct hist_var var; + enum field_op_id operator; + char *name; }; static u64 hist_field_none(struct hist_field *field, void *event, @@ -98,6 +107,41 @@ static u64 hist_field_log2(struct hist_field *hist_field, void *event, return (u64) ilog2(roundup_pow_of_two(val)); } +static u64 hist_field_plus(struct hist_field *hist_field, void *event, + struct ring_buffer_event *rbe) +{ + struct hist_field *operand1 = hist_field->operands[0]; + struct hist_field *operand2 = hist_field->operands[1]; + + u64 val1 = operand1->fn(operand1, event, rbe); + u64 val2 = operand2->fn(operand2, event, rbe); + + return val1 + val2; +} + +static u64 hist_field_minus(struct hist_field *hist_field, void *event, + struct ring_buffer_event *rbe) +{ + struct hist_field *operand1 = hist_field->operands[0]; + struct hist_field *operand2 = hist_field->operands[1]; + + u64 val1 = operand1->fn(operand1, event, rbe); + u64 val2 = operand2->fn(operand2, event, rbe); + + return val1 - val2; +} + +static u64 hist_field_unary_minus(struct hist_field *hist_field, void *event, + struct ring_buffer_event *rbe) +{ + struct hist_field *operand = hist_field->operands[0]; + + s64 sval = (s64)operand->fn(operand, event, rbe); + u64 val = (u64)-sval; + + return val; +} + #define DEFINE_HIST_FIELD_FN(type) \ static u64 hist_field_##type(struct hist_field *hist_field, \ void *event, \ @@ -148,6 +192,7 @@ enum hist_field_flags { HIST_FIELD_FL_TIMESTAMP_USECS = 2048, HIST_FIELD_FL_VAR = 4096, HIST_FIELD_FL_VAR_ONLY = 8192, + HIST_FIELD_FL_EXPR = 16384, }; struct hist_trigger_attrs { @@ -210,6 +255,8 @@ static const char *hist_field_name(struct hist_field *field, field_name = hist_field_name(field->operands[0], ++level); else if (field->flags & HIST_FIELD_FL_TIMESTAMP) field_name = "$common_timestamp"; + else if (field->flags & HIST_FIELD_FL_EXPR) + field_name = field->name; if (field_name == NULL) field_name = ""; @@ -444,6 +491,73 @@ static void hist_trigger_elt_comm_init(struct tracing_map_elt *elt) .elt_init = hist_trigger_elt_comm_init, }; +static char *expr_str(struct hist_field *field, unsigned int level) +{ + char *expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL); + + if (!expr || level > 1) + return NULL; + + if (field->operator == FIELD_OP_UNARY_MINUS) { + char *subexpr; + + strcat(expr, "-("); + subexpr = expr_str(field->operands[0], ++level); + if (!subexpr) { + kfree(expr); + return NULL; + } + strcat(expr, subexpr); + strcat(expr, ")"); + + return expr; + } + + strcat(expr, hist_field_name(field->operands[0], 0)); + + switch (field->operator) { + case FIELD_OP_MINUS: + strcat(expr, "-"); + break; + case FIELD_OP_PLUS: + strcat(expr, "+"); + break; + default: + kfree(expr); + return NULL; + } + + strcat(expr, hist_field_name(field->operands[1], 0)); + + return expr; +} + +static int contains_operator(char *str) +{ + enum field_op_id field_op = FIELD_OP_NONE; + char *op; + + op = strpbrk(str, "+-"); + if (!op) + return FIELD_OP_NONE; + + switch (*op) { + case '-': + if (*str == '-') + field_op = FIELD_OP_UNARY_MINUS; + else + field_op = FIELD_OP_MINUS; + break; + case '+': + field_op = FIELD_OP_PLUS; + break; + default: + break; + } + + return field_op; +} + static void destroy_hist_field(struct hist_field *hist_field, unsigned int level) { @@ -459,6 +573,7 @@ static void destroy_hist_field(struct hist_field *hist_field, destroy_hist_field(hist_field->operands[i], ++level); kfree(hist_field->var.name); + kfree(hist_field->name); kfree(hist_field); } @@ -479,6 +594,9 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, hist_field->hist_data = hist_data; + if (flags & HIST_FIELD_FL_EXPR) + goto out; /* caller will populate */ + if (flags & HIST_FIELD_FL_HITCOUNT) { hist_field->fn = hist_field_counter; goto out; @@ -551,6 +669,247 @@ static void destroy_hist_fields(struct hist_trigger_data *hist_data) } } +static struct ftrace_event_field * +parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file, + char *field_str, unsigned long *flags) +{ + struct ftrace_event_field *field = NULL; + char *field_name; + + field_name = strsep(&field_str, "."); + if (field_str) { + if (strcmp(field_str, "hex") == 0) + *flags |= HIST_FIELD_FL_HEX; + else if (strcmp(field_str, "sym") == 0) + *flags |= HIST_FIELD_FL_SYM; + else if (strcmp(field_str, "sym-offset") == 0) + *flags |= HIST_FIELD_FL_SYM_OFFSET; + else if ((strcmp(field_str, "execname") == 0) && + (strcmp(field_name, "common_pid") == 0)) + *flags |= HIST_FIELD_FL_EXECNAME; + else if (strcmp(field_str, "syscall") == 0) + *flags |= HIST_FIELD_FL_SYSCALL; + else if (strcmp(field_str, "log2") == 0) + *flags |= HIST_FIELD_FL_LOG2; + else if (strcmp(field_str, "usecs") == 0) + *flags |= HIST_FIELD_FL_TIMESTAMP_USECS; + else + return ERR_PTR(-EINVAL); + } + + if (strcmp(field_name, "$common_timestamp") == 0) { + *flags |= HIST_FIELD_FL_TIMESTAMP; + hist_data->enable_timestamps = true; + if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS) + hist_data->attrs->ts_in_usecs = true; + } else { + field = trace_find_event_field(file->event_call, field_name); + if (!field) + return ERR_PTR(-EINVAL); + } + + return field; +} + +struct hist_field *parse_atom(struct hist_trigger_data *hist_data, + struct trace_event_file *file, char *str, + unsigned long *flags, char *var_name) +{ + struct ftrace_event_field *field = NULL; + struct hist_field *hist_field = NULL; + int ret = 0; + + field = parse_field(hist_data, file, str, flags); + if (IS_ERR(field)) { + ret = PTR_ERR(field); + goto out; + } + + hist_field = create_hist_field(hist_data, field, *flags, var_name); + if (!hist_field) { + ret = -ENOMEM; + goto out; + } + + return hist_field; + out: + return ERR_PTR(ret); +} + +static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, + struct trace_event_file *file, + char *str, unsigned long flags, + char *var_name, unsigned int level); + +static struct hist_field *parse_unary(struct hist_trigger_data *hist_data, + struct trace_event_file *file, + char *str, unsigned long flags, + char *var_name, unsigned int level) +{ + struct hist_field *operand1, *expr = NULL; + unsigned long operand_flags; + char *operand1_str; + int ret = 0; + char *s; + + // we support only -(xxx) i.e. explicit parens required + + if (level > 2) { + ret = -EINVAL; + goto free; + } + + str++; // skip leading '-' + + s = strchr(str, '('); + if (s) + str++; + else { + ret = -EINVAL; + goto free; + } + + s = strchr(str, ')'); + if (s) + *s = '\0'; + else { + ret = -EINVAL; // no closing ')' + goto free; + } + + operand1_str = strsep(&str, "("); + if (!operand1_str) + goto free; + + flags |= HIST_FIELD_FL_EXPR; + expr = create_hist_field(hist_data, NULL, flags, var_name); + if (!expr) { + ret = -ENOMEM; + goto free; + } + + operand_flags = 0; + operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level); + if (IS_ERR(operand1)) { + ret = PTR_ERR(operand1); + goto free; + } + + if (operand1 == NULL) { + operand_flags = 0; + operand1 = parse_atom(hist_data, file, operand1_str, + &operand_flags, NULL); + if (IS_ERR(operand1)) { + ret = PTR_ERR(operand1); + goto free; + } + } + + expr->fn = hist_field_unary_minus; + expr->operands[0] = operand1; + expr->operator = FIELD_OP_UNARY_MINUS; + expr->name = expr_str(expr, 0); + + return expr; + free: + return ERR_PTR(ret); +} + +static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, + struct trace_event_file *file, + char *str, unsigned long flags, + char *var_name, unsigned int level) +{ + struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL; + unsigned long operand_flags; + int field_op, ret = -EINVAL; + char *sep, *operand1_str; + + if (level > 2) + return NULL; + + field_op = contains_operator(str); + if (field_op == FIELD_OP_NONE) + return NULL; + + if (field_op == FIELD_OP_UNARY_MINUS) + return parse_unary(hist_data, file, str, flags, var_name, ++level); + + switch (field_op) { + case FIELD_OP_MINUS: + sep = "-"; + break; + case FIELD_OP_PLUS: + sep = "+"; + break; + default: + goto free; + } + + operand1_str = strsep(&str, sep); + if (!operand1_str || !str) + goto free; + + operand_flags = 0; + operand1 = parse_atom(hist_data, file, operand1_str, + &operand_flags, NULL); + if (IS_ERR(operand1)) { + ret = PTR_ERR(operand1); + operand1 = NULL; + goto free; + } + + // rest of string could be another expression e.g. b+c in a+b+c + operand_flags = 0; + operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level); + if (IS_ERR(operand2)) { + ret = PTR_ERR(operand2); + operand2 = NULL; + goto free; + } + if (!operand2) { + operand_flags = 0; + operand2 = parse_atom(hist_data, file, str, + &operand_flags, NULL); + if (IS_ERR(operand2)) { + ret = PTR_ERR(operand2); + operand2 = NULL; + goto free; + } + } + + flags |= HIST_FIELD_FL_EXPR; + expr = create_hist_field(hist_data, NULL, flags, var_name); + if (!expr) { + ret = -ENOMEM; + goto free; + } + + expr->operands[0] = operand1; + expr->operands[1] = operand2; + expr->operator = field_op; + expr->name = expr_str(expr, 0); + + switch (field_op) { + case FIELD_OP_MINUS: + expr->fn = hist_field_minus; + break; + case FIELD_OP_PLUS: + expr->fn = hist_field_plus; + break; + default: + goto free; + } + + return expr; + free: + destroy_hist_field(operand1, 0); + destroy_hist_field(operand2, 0); + destroy_hist_field(expr, 0); + + return ERR_PTR(ret); +} + static int create_hitcount_val(struct hist_trigger_data *hist_data) { hist_data->fields[HITCOUNT_IDX] = @@ -609,9 +968,9 @@ static int create_val_field(struct hist_trigger_data *hist_data, struct trace_event_file *file, char *field_str, bool var_only) { - struct ftrace_event_field *field = NULL; - char *field_name, *var_name; + struct hist_field *hist_field; unsigned long flags = 0; + char *var_name; int ret = 0; if (WARN_ON(!var_only && val_idx >= TRACING_MAP_VALS_MAX)) @@ -642,37 +1001,27 @@ static int create_val_field(struct hist_trigger_data *hist_data, goto out; } - field_name = strsep(&field_str, "."); - if (field_str) { - if (strcmp(field_str, "hex") == 0) - flags |= HIST_FIELD_FL_HEX; - else { - ret = -EINVAL; - goto out; - } + hist_field = parse_expr(hist_data, file, field_str, flags, var_name, 0); + if (IS_ERR(hist_field)) { + ret = PTR_ERR(hist_field); + goto out; } - if (strcmp(field_name, "$common_timestamp") == 0) { - flags |= HIST_FIELD_FL_TIMESTAMP; - hist_data->enable_timestamps = true; - } else { - field = trace_find_event_field(file->event_call, field_name); - if (!field) { - ret = -EINVAL; + if (!hist_field) { + hist_field = parse_atom(hist_data, file, field_str, + &flags, var_name); + if (IS_ERR(hist_field)) { + ret = PTR_ERR(hist_field); goto out; } } - hist_data->fields[val_idx] = create_hist_field(hist_data, field, flags, var_name); - if (!hist_data->fields[val_idx]) { - ret = -ENOMEM; - goto out; - } + hist_data->fields[val_idx] = hist_field; ++hist_data->n_vals; ++hist_data->n_fields; - if (hist_data->fields[val_idx]->flags & HIST_FIELD_FL_VAR_ONLY) + if (hist_field->flags & HIST_FIELD_FL_VAR_ONLY) hist_data->n_var_only++; if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX)) @@ -726,8 +1075,8 @@ static int create_key_field(struct hist_trigger_data *hist_data, struct trace_event_file *file, char *field_str) { - struct ftrace_event_field *field = NULL; struct hist_field *hist_field = NULL; + unsigned long flags = 0; unsigned int key_size; char *var_name; @@ -754,60 +1103,33 @@ static int create_key_field(struct hist_trigger_data *hist_data, key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH; hist_field = create_hist_field(hist_data, NULL, flags, var_name); } else { - char *field_name = strsep(&field_str, "."); - - if (field_str) { - if (strcmp(field_str, "hex") == 0) - flags |= HIST_FIELD_FL_HEX; - else if (strcmp(field_str, "sym") == 0) - flags |= HIST_FIELD_FL_SYM; - else if (strcmp(field_str, "sym-offset") == 0) - flags |= HIST_FIELD_FL_SYM_OFFSET; - else if ((strcmp(field_str, "execname") == 0) && - (strcmp(field_name, "common_pid") == 0)) - flags |= HIST_FIELD_FL_EXECNAME; - else if (strcmp(field_str, "syscall") == 0) - flags |= HIST_FIELD_FL_SYSCALL; - else if (strcmp(field_str, "log2") == 0) - flags |= HIST_FIELD_FL_LOG2; - else if (strcmp(field_str, "usecs") == 0) - flags |= HIST_FIELD_FL_TIMESTAMP_USECS; - else { - ret = -EINVAL; - goto out; - } + hist_field = parse_expr(hist_data, file, field_str, flags, + var_name, 0); + if (IS_ERR(hist_field)) { + ret = PTR_ERR(hist_field); + goto out; } - if (strcmp(field_name, "$common_timestamp") == 0) { - flags |= HIST_FIELD_FL_TIMESTAMP; - hist_data->enable_timestamps = true; - if (flags & HIST_FIELD_FL_TIMESTAMP_USECS) - hist_data->attrs->ts_in_usecs = true; - key_size = sizeof(u64); - } else { - field = trace_find_event_field(file->event_call, field_name); - if (!field) { - ret = -EINVAL; + if (!hist_field) { + hist_field = parse_atom(hist_data, file, field_str, + &flags, var_name); + if (IS_ERR(hist_field)) { + ret = PTR_ERR(hist_field); goto out; } - - if (is_string_field(field)) - key_size = MAX_FILTER_STR_VAL; - else - key_size = field->size; } - } - hist_data->fields[key_idx] = create_hist_field(hist_data, field, flags, var_name); - if (!hist_data->fields[key_idx]) { - ret = -ENOMEM; - goto out; + key_size = hist_field->size; } + hist_data->fields[key_idx] = hist_field; + key_size = ALIGN(key_size, sizeof(u64)); hist_data->fields[key_idx]->size = key_size; hist_data->fields[key_idx]->offset = key_offset; + hist_data->key_size += key_size; + if (hist_data->key_size > HIST_KEY_SIZE_MAX) { ret = -EINVAL; goto out; @@ -1330,7 +1652,8 @@ static void hist_trigger_stacktrace_print(struct seq_file *m, for (i = 1; i < hist_data->n_vals; i++) { field_name = hist_field_name(hist_data->fields[i], 0); - if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR) + if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR || + hist_data->fields[i]->flags & HIST_FIELD_FL_EXPR) continue; if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) { -- 1.9.3