From 100719dcef447aa0c90301f919e81ae477b32bf2 Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Mon, 15 Jan 2018 20:51:52 -0600 Subject: [PATCH] tracing: Add simple expression support to hist triggers 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. Link: http://lkml.kernel.org/r/9a9308ead4fe32a433d9c7e95921fb798394f6b2.1516069914.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi [kbuild test robot fix, add static to parse_atom()] Signed-off-by: Fengguang Wu [ Replaced '//' comments with normal /* */ comments ] Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_hist.c | 487 ++++++++++++++++++++++++++----- 1 file changed, 413 insertions(+), 74 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index a81a709dc703..4c3c7d784bfd 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, \ @@ -147,6 +191,7 @@ enum hist_field_flags { HIST_FIELD_FL_TIMESTAMP = 1 << 10, HIST_FIELD_FL_TIMESTAMP_USECS = 1 << 11, HIST_FIELD_FL_VAR = 1 << 12, + HIST_FIELD_FL_EXPR = 1 << 13, }; struct var_defs { @@ -258,6 +303,8 @@ 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 = ""; @@ -519,12 +566,104 @@ static const char *get_hist_field_flags(struct hist_field *hist_field) return flags_str; } +static void expr_field_str(struct hist_field *field, char *expr) +{ + strcat(expr, hist_field_name(field, 0)); + + if (field->flags) { + const char *flags_str = get_hist_field_flags(field); + + if (flags_str) { + strcat(expr, "."); + strcat(expr, flags_str); + } + } +} + +static char *expr_str(struct hist_field *field, unsigned int level) +{ + char *expr; + + if (level > 1) + return NULL; + + expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL); + if (!expr) + return NULL; + + if (!field->operands[0]) { + expr_field_str(field, expr); + return expr; + } + + 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, ")"); + + kfree(subexpr); + + return expr; + } + + expr_field_str(field->operands[0], expr); + + switch (field->operator) { + case FIELD_OP_MINUS: + strcat(expr, "-"); + break; + case FIELD_OP_PLUS: + strcat(expr, "+"); + break; + default: + kfree(expr); + return NULL; + } + + expr_field_str(field->operands[1], expr); + + 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) { unsigned int i; - if (level > 2) + if (level > 3) return; if (!hist_field) @@ -534,6 +673,7 @@ static void destroy_hist_field(struct hist_field *hist_field, destroy_hist_field(hist_field->operands[i], level + 1); kfree(hist_field->var.name); + kfree(hist_field->name); kfree(hist_field); } @@ -554,6 +694,9 @@ 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; @@ -626,6 +769,257 @@ 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, *modifier, *str; + + modifier = str = kstrdup(field_str, GFP_KERNEL); + if (!modifier) + return ERR_PTR(-ENOMEM); + + field_name = strsep(&modifier, "."); + if (modifier) { + if (strcmp(modifier, "hex") == 0) + *flags |= HIST_FIELD_FL_HEX; + else if (strcmp(modifier, "sym") == 0) + *flags |= HIST_FIELD_FL_SYM; + else if (strcmp(modifier, "sym-offset") == 0) + *flags |= HIST_FIELD_FL_SYM_OFFSET; + else if ((strcmp(modifier, "execname") == 0) && + (strcmp(field_name, "common_pid") == 0)) + *flags |= HIST_FIELD_FL_EXECNAME; + else if (strcmp(modifier, "syscall") == 0) + *flags |= HIST_FIELD_FL_SYSCALL; + else if (strcmp(modifier, "log2") == 0) + *flags |= HIST_FIELD_FL_LOG2; + else if (strcmp(modifier, "usecs") == 0) + *flags |= HIST_FIELD_FL_TIMESTAMP_USECS; + else { + field = ERR_PTR(-EINVAL); + 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; + } else { + field = trace_find_event_field(file->event_call, field_name); + if (!field || !field->size) { + field = ERR_PTR(-EINVAL); + goto out; + } + } + out: + kfree(str); + + 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) +{ + 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; + int ret = 0; + char *s; + + /* we support only -(xxx) i.e. explicit parens required */ + + if (level > 3) { + ret = -EINVAL; + goto free; + } + + str++; /* skip leading '-' */ + + s = strchr(str, '('); + if (s) + str++; + else { + ret = -EINVAL; + goto free; + } + + s = strrchr(str, ')'); + if (s) + *s = '\0'; + else { + ret = -EINVAL; /* no closing ')' */ + 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; + } + + expr->flags |= operand1->flags & + (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS); + 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: + destroy_hist_field(expr, 0); + return ERR_PTR(ret); +} + +static int check_expr_operands(struct hist_field *operand1, + struct hist_field *operand2) +{ + unsigned long operand1_flags = operand1->flags; + unsigned long operand2_flags = operand2->flags; + + if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) != + (operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) + return -EINVAL; + + return 0; +} + +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 > 3) + return ERR_PTR(-EINVAL); + + field_op = contains_operator(str); + + if (field_op == FIELD_OP_NONE) + return parse_atom(hist_data, file, str, &flags, var_name); + + 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; + } + + ret = check_expr_operands(operand1, operand2); + if (ret) + goto free; + + flags |= HIST_FIELD_FL_EXPR; + + flags |= operand1->flags & + (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS); + + 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] = @@ -648,37 +1042,17 @@ static int __create_val_field(struct hist_trigger_data *hist_data, char *var_name, char *field_str, unsigned long flags) { - struct ftrace_event_field *field = NULL; - char *field_name; + struct hist_field *hist_field; int ret = 0; - field_name = strsep(&field_str, "."); - if (field_str) { - if (strcmp(field_str, "hex") == 0) - flags |= HIST_FIELD_FL_HEX; - else { - ret = -EINVAL; - 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 || !field->size) { - ret = -EINVAL; - goto out; - } - } - - hist_data->fields[val_idx] = create_hist_field(hist_data, field, flags, var_name); - if (!hist_data->fields[val_idx]) { - ret = -ENOMEM; + 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; } + hist_data->fields[val_idx] = hist_field; + ++hist_data->n_vals; ++hist_data->n_fields; @@ -765,8 +1139,8 @@ 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; int ret = 0; @@ -781,60 +1155,24 @@ 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, NULL); } 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, + NULL, 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 || !field->size) { - ret = -EINVAL; - goto out; - } - - if (is_string_field(field)) - key_size = MAX_FILTER_STR_VAL; - else - key_size = field->size; - } + key_size = hist_field->size; } - hist_data->fields[key_idx] = create_hist_field(hist_data, field, flags, NULL); - if (!hist_data->fields[key_idx]) { - ret = -ENOMEM; - goto out; - } + 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; @@ -1419,7 +1757,8 @@ hist_trigger_entry_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) { -- 2.30.2