Messages in this thread | | | Date | Wed, 7 Jun 2017 08:42:24 +0900 | From | Byungchul Park <> | Subject | Re: [PATCH 2/2] sched/deadline: Don't return invalid cpu in cpudl_maximum_cpu() |
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On Tue, Jun 06, 2017 at 04:12:25PM +0100, Juri Lelli wrote: > Hi, > > On 02/06/17 16:31, Byungchul Park wrote: > > When the heap tree is empty, cp->elements[0].cpu has meaningless value.
Hi,
The meaningless value is 0.
> > We need to consider the case. > > > > Signed-off-by: Byungchul Park <byungchul.park@lge.com> > > --- > > kernel/sched/cpudeadline.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c > > index d4a6963..9b314a9 100644 > > --- a/kernel/sched/cpudeadline.c > > +++ b/kernel/sched/cpudeadline.c > > @@ -110,7 +110,8 @@ static void cpudl_heapify(struct cpudl *cp, int idx) > > > > static inline int cpudl_maximum_cpu(struct cpudl *cp) > > { > > - return cp->elements[0].cpu; > > + int cpu = cp->elements[0].cpu; > > + return cp->elements[cpu].idx == IDX_INVALID ? -1 : cpu; > > Mmm, don't we get a WARN from cpumask_check() if we return -1 here?
The function does not return -1 without my patch.
Right?
> > Thanks, > > - Juri
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