On 29/07/23 15:55, Steven Rostedt wrote: > On Thu, 20 Jul 2023 17:30:42 +0100 > Valentin Schneider <vschneid@xxxxxxxxxx> wrote: > >> Steven noted that when the user-provided cpumask contains a single CPU, >> then the filtering function can use a scalar as input instead of a >> full-fledged cpumask. >> >> When the mask contains a single CPU, directly re-use the unsigned field >> predicate functions. Transform '&' into '==' beforehand. >> >> Suggested-by: Steven Rostedt <rostedt@xxxxxxxxxxx> >> Signed-off-by: Valentin Schneider <vschneid@xxxxxxxxxx> >> --- >> kernel/trace/trace_events_filter.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c >> index 2fe65ddeb34ef..54d642fabb7f1 100644 >> --- a/kernel/trace/trace_events_filter.c >> +++ b/kernel/trace/trace_events_filter.c >> @@ -1750,7 +1750,7 @@ static int parse_pred(const char *str, void *data, >> * then we can treat it as a scalar input. >> */ >> single = cpumask_weight(pred->mask) == 1; >> - if (single && field->filter_type == FILTER_CPUMASK) { >> + if (single && field->filter_type != FILTER_CPU) { >> pred->val = cpumask_first(pred->mask); >> kfree(pred->mask); >> } >> @@ -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; > That's neater, thanks! > -- Steve > > >> + pred->fn_num = select_comparison_fn(pred->op, field->size, false); >> + if (pred->op == OP_NE) >> + pred->not = 1; >> } else { >> switch (field->size) { >> case 8: