Messages in this thread | | | Subject | Re: [PATCH 18/32] tracing: Add simple expression support to hist triggers | From | Tom Zanussi <> | Date | Fri, 21 Jul 2017 11:29:19 -0500 |
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Hi Namhyung,
On Fri, 2017-07-21 at 11:02 +0900, Namhyung Kim wrote: > Hi Tom, > > On Mon, Jun 26, 2017 at 05:49:19PM -0500, Tom Zanussi wrote: > > 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 <tom.zanussi@linux.intel.com> > > --- > > [SNIP] > > +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; > > Looks like a memory leak. > >
Indeed, and so obvious I can't believe I missed it. Thanks for pointing it out.
> [SNIP] > > +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; > > Why not calling parse_atom() here? It'd make the code simpler IMHO. >
Yeah, I think that would be much nicer, will do.
Thanks,
Tom
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