RE: [RFC PATCH v2 11/23] sched/cache: Introduce helpers for task migration decisions

[Jianyong Wu]

> -----Original Message-----
> From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Sent: Tuesday, September 1, 2026 7:32 PM
> To: Jianyong Wu <wujianyong@xxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>; Juri Lelli <juri.lelli@xxxxxxxxxx>;
> Vincent Guittot <vincent.guittot@xxxxxxxxxx>; Chen Yu
> <yu.c.chen@xxxxxxxxx>; Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>; Dietmar
> Eggemann <dietmar.eggemann@xxxxxxx>; Steven Rostedt
> <rostedt@xxxxxxxxxxx>; Ben Segall <bsegall@xxxxxxxxxx>; Mel Gorman
> <mgorman@xxxxxxx>; Valentin Schneider <vschneid@xxxxxxxxxx>; K
> Prateek Nayak <kprateek.nayak@xxxxxxx>; Shrikanth Hegde
> <sshegde@xxxxxxxxxxxxx>; Phil Auld <pauld@xxxxxxxxxx>; Andrew
> Morton <akpm@xxxxxxxxxxxxxxxxxxxx>; David Hildenbrand
> <david@xxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx;
> jianyong.wu@xxxxxxxxxxx; Yuan Zhong <zhongyuan@xxxxxxxx>; Huangsj
> <huangsj@xxxxxxxx>; Fengyu Wang <wangfengyu@xxxxxxxx>; Zhiwei Ying
> <yingzhiwei@xxxxxxxx>; justin.he@xxxxxxx
> Subject: Re: [RFC PATCH v2 11/23] sched/cache: Introduce helpers for task
> migration decisions
> 
> On Thu, Aug 27, 2026 at 08:28:04PM +0800, Jianyong Wu wrote:
> 
> > +static bool get_span_stats(const struct cpumask *span, unsigned long
> *util_out,
> > +					unsigned long *cap_out)
> > +{
> > +	cpumask_var_t mask;
> > +	int cpu;
> > +	unsigned long util_tmp, cap_tmp, util = 0, cap = 0;
> > +	struct sched_domain *sd_tmp;
> > +
> 
> We prefer inverse xmas ordering -- where possible. So please go through
> the code and re-arrange things. Eg. the above becomes:
> 
OK, I'll go through the patch and re-order the variable declarations into
inverse christmas tree style.

Thanks
Jianyong
> > +	unsigned long util_tmp, cap_tmp, util = 0, cap = 0;
> > +	struct sched_domain *sd_tmp;
> > +	cpumask_var_t mask;
> > +	int cpu;