Re: Re: [PATCH v2 2/3] cgroup/rstat: Cleanup cpu.stat once for all

[Abel Wu <wuyun.abel@bytedance.com>]

Hi Tejun,

On 1/28/25 4:17 AM, Tejun Heo Wrote:
> On Sat, Jan 25, 2025 at 01:25:11PM +0800, Abel Wu wrote:
>> There were efforts like b824766504e4 ("cgroup/rstat: add force idle show helper")
>> to escape from #ifdef hells, and there could be new stats coming out in
>> the future, let's clean it up once for all.
>>
>> Signed-off-by: Abel Wu <wuyun.abel@bytedance.com>
>> ---
>>   kernel/cgroup/rstat.c | 47 ++++++++++++++++++++++++-------------------
>>   1 file changed, 26 insertions(+), 21 deletions(-)
> 
> Is this materially better? The existing code has ifdef in one place which
> the new code can't avoid. 

Indeed, # of ifdefs will stay unchanged, but they will be folded
into one place inside the bstats[] array quite the same as the
definition of the struct cgroup_base_stat, which IMHO won't hurt
readability.

> The new code is more complex and has more lines.
> Does the balance get better with additions of new entries?

The line diff is 5, and 4 of them are for readability. If adding
one more field into cpu.stat, 1 or 3 lines will be added w/o or
w/ ifdef respectively, comparing to 8 or 10 lines without this
cleanup. So the balance will be better if cpu.stat extends. And
it would also be better cleanup duplicated code for each field.

Thanks,
	Abel