Commit 3347d80b authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
Browse files

tracing: Have histogram types be constant when possible 

Instead of kstrdup("const", GFP_KERNEL), have the hist_field type simply
assign the constant hist_field->type = "const"; And when the value passed
to it is a variable, use "kstrdup_const(var, GFP_KERNEL);" which will just
copy the value if the variable is already a constant. This saves on having
to allocate when not needed.

All frees of the hist_field->type will need to use kfree_const().

Link: https://lkml.kernel.org/r/20210722142837.280718447@goodmis.org



Suggested-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 37036435

kernel/trace/trace_events_hist.c

+14 −18
Original line number Diff line number Diff line
@@ -1616,7 +1616,9 @@ static void __destroy_hist_field(struct hist_field *hist_field) 


	kfree(hist_field->var.name);

	kfree(hist_field->name);

	kfree(hist_field->type);



	/* Can likely be a const */

	kfree_const(hist_field->type);



	kfree(hist_field->system);

	kfree(hist_field->event_name);
@@ -1673,9 +1675,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, 
	if (flags & HIST_FIELD_FL_HITCOUNT) {

		hist_field->fn = hist_field_counter;

		hist_field->size = sizeof(u64);

		hist_field->type = kstrdup("u64", GFP_KERNEL);

		if (!hist_field->type)

			goto free;

		hist_field->type = "u64";

		goto out;

	}
@@ -1690,7 +1690,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, 
			hist_field_bucket;

		hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);

		hist_field->size = hist_field->operands[0]->size;

		hist_field->type = kstrdup(hist_field->operands[0]->type, GFP_KERNEL);

		hist_field->type = kstrdup_const(hist_field->operands[0]->type, GFP_KERNEL);

		if (!hist_field->type)

			goto free;

		goto out;
@@ -1699,18 +1699,14 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, 
	if (flags & HIST_FIELD_FL_TIMESTAMP) {

		hist_field->fn = hist_field_timestamp;

		hist_field->size = sizeof(u64);

		hist_field->type = kstrdup("u64", GFP_KERNEL);

		if (!hist_field->type)

			goto free;

		hist_field->type = "u64";

		goto out;

	}



	if (flags & HIST_FIELD_FL_CPU) {

		hist_field->fn = hist_field_cpu;

		hist_field->size = sizeof(int);

		hist_field->type = kstrdup("unsigned int", GFP_KERNEL);

		if (!hist_field->type)

			goto free;

		hist_field->type = "unsigned int";

		goto out;

	}
@@ -1723,7 +1719,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, 
		flags |= HIST_FIELD_FL_STRING;



		hist_field->size = MAX_FILTER_STR_VAL;

		hist_field->type = kstrdup(field->type, GFP_KERNEL);

		hist_field->type = kstrdup_const(field->type, GFP_KERNEL);

		if (!hist_field->type)

			goto free;
@@ -1736,7 +1732,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, 
	} else {

		hist_field->size = field->size;

		hist_field->is_signed = field->is_signed;

		hist_field->type = kstrdup(field->type, GFP_KERNEL);

		hist_field->type = kstrdup_const(field->type, GFP_KERNEL);

		if (!hist_field->type)

			goto free;
@@ -1822,7 +1818,7 @@ static int init_var_ref(struct hist_field *ref_field, 
		}

	}



	ref_field->type = kstrdup(var_field->type, GFP_KERNEL);

	ref_field->type = kstrdup_const(var_field->type, GFP_KERNEL);

	if (!ref_field->type) {

		err = -ENOMEM;

		goto free;
@@ -2215,7 +2211,7 @@ static struct hist_field *parse_unary(struct hist_trigger_data *hist_data, 
	expr->operands[0] = operand1;

	expr->operator = FIELD_OP_UNARY_MINUS;

	expr->name = expr_str(expr, 0);

	expr->type = kstrdup(operand1->type, GFP_KERNEL);

	expr->type = kstrdup_const(operand1->type, GFP_KERNEL);

	if (!expr->type) {

		ret = -ENOMEM;

		goto free;
@@ -2355,7 +2351,7 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, 


	expr->operator = field_op;

	expr->name = expr_str(expr, 0);

	expr->type = kstrdup(operand1->type, GFP_KERNEL);

	expr->type = kstrdup_const(operand1->type, GFP_KERNEL);

	if (!expr->type) {

		ret = -ENOMEM;

		goto free;
@@ -2743,10 +2739,10 @@ static struct hist_field *create_var(struct hist_trigger_data *hist_data, 
	var->var.hist_data = var->hist_data = hist_data;

	var->size = size;

	var->var.name = kstrdup(name, GFP_KERNEL);

	var->type = kstrdup(type, GFP_KERNEL);

	var->type = kstrdup_const(type, GFP_KERNEL);

	if (!var->var.name || !var->type) {

		kfree_const(var->type);

		kfree(var->var.name);

		kfree(var->type);

		kfree(var);

		var = ERR_PTR(-ENOMEM);

	}