linux-kernel - Re: [RFC PATCH v2 06/20] tracing/filters: Optimise scalar vs cpumask filtering when the user mask is a single CPU

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Message-ID: <04f20e58-6b24-4f44-94e2-0d12324a30e4@kadam.mountain>
Date:   Mon, 31 Jul 2023 15:07:52 +0300
From:   Dan Carpenter <dan.carpenter@...aro.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Valentin Schneider <vschneid@...hat.com>,
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Subject: Re: [RFC PATCH v2 06/20] tracing/filters: Optimise scalar vs cpumask
 filtering when the user mask is a single CPU

On Sat, Jul 29, 2023 at 03:55:47PM -0400, Steven Rostedt wrote:
> > @@ -1761,6 +1761,11 @@ static int parse_pred(const char *str, void *data,
> >  				FILTER_PRED_FN_CPUMASK;
> >  		} else if (field->filter_type == FILTER_CPU) {
> >  			pred->fn_num = FILTER_PRED_FN_CPU_CPUMASK;
> > +		} else if (single) {
> > +			pred->op = pred->op == OP_BAND ? OP_EQ : pred->op;
> 
> Nit, the above can be written as:
> 
> 			pred->op = pret->op != OP_BAND ? : OP_EQ;
> 

Heh.  Those are not equivalent.  The right way to write this is:

	if (pred->op == OP_BAND)
		pred->op = OP_EQ;

regards,
dan carpenter