Re: [PATCH] sched: Remove unnecessary initialization in init_cfs_bandwidth() function

[yaoma]

在 2024/11/4 20:18, Peter Zijlstra 写道:
> On Mon, Nov 04, 2024 at 08:14:43PM +0800, Bitao Hu wrote:
> > The root task group is statically defined, and non-root task groups
> > are allocated memory using kmem_cache_alloc() with the __GFP_ZERO
> > flag. In both cases, the corresponding 'struct cfs_bandwidth' is a
> > block of all-zero memory. Therefore, it is unnecessary to explicitly
> > set zeros in the init_cfs_bandwidth() function.
> >
> > Signed-off-by: Bitao Hu <yaoma@xxxxxxxxxxxxxxxxx>
> > ---
> >   kernel/sched/fair.c | 2 --
> >   1 file changed, 2 deletions(-)
> >
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index 2d16c8545c71..2fd96641164f 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -6573,10 +6573,8 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
> >   void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b, struct cfs_bandwidth *parent)
> >   {
> >   	raw_spin_lock_init(&cfs_b->lock);
> > -	cfs_b->runtime = 0;
> >   	cfs_b->quota = RUNTIME_INF;
> >   	cfs_b->period = ns_to_ktime(default_cfs_period());
> > -	cfs_b->burst = 0;
> >   	cfs_b->hierarchical_quota = parent ? parent->hierarchical_quota : RUNTIME_INF;
> >   
> >   	INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq);
>
> But this shows someone thought about it and 0 is the right value, and
> not an oversight.

Okay, I got it.