linux-kernel - Re: [PATCH 2/2] tracing/hist: add modulus operator

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Message-ID: <20230318151902.78809fbe@rorschach.local.home>
Date:   Sat, 18 Mar 2023 15:19:02 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Mark Rutland <mark.rutland@....com>
Cc:     linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
        mhiramat@...nel.org, zanussi@...nel.org
Subject: Re: [PATCH 2/2] tracing/hist: add modulus operator

On Thu,  2 Mar 2023 17:17:55 +0000
Mark Rutland <mark.rutland@....com> wrote:

> @@ -436,6 +438,21 @@ static u64 hist_field_mult(struct hist_field *hist_field,
>  	return val1 * val2;
>  }
>  
> +static u64 hist_field_mod(struct hist_field *hist_field,
> +			  struct tracing_map_elt *elt,
> +			  struct trace_buffer *buffer,
> +			  struct ring_buffer_event *rbe,
> +			  void *event)
> +{
> +	struct hist_field *operand1 = hist_field->operands[0];
> +	struct hist_field *operand2 = hist_field->operands[1];
> +
> +	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
> +	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
> +
> +	return val1 % val2;

Is modulus operations on 64 bit integers valid on 32 bit architectures?

Don't we need to do something like:

	div64_u64_rem(val1, val2, &rem);
	return rem;

?

-- Steve


> +}
> +