Re: [PATCH] proc/schedstat: Expose /proc/<pid>/schedstat if delay accounting is enabled

From: Cong Wang
Date: Thu Jun 25 2015 - 14:00:45 EST


On Thu, May 28, 2015 at 2:11 AM, Balbir Singh <bsingharora@xxxxxxxxx> wrote:
> On Mon, May 25, 2015 at 12:42 PM, Naveen N. Rao
> <naveen.n.rao@xxxxxxxxxxxxxxxxxx> wrote:
>> /proc/<pid>/schedstat is currently only available if CONFIG_SCHEDSTATS is
>> enabled. But, all the fields that this exposes are available and valid
>> if CONFIG_TASK_DELAY_ACCT is enabled as well.
>>

[...]

> The change looks reasonable, from what I can understand you want these
> changes so that you can use /proc/<pid>/schedstat instead of the
> netlink interface when CONFIG_TASK_DELAY_ACCT is enabled.
>

Why?

If you need the procfs interface, just enable CONFIG_SCHEDSTATS.
If you need the netlink interface, enable CONFIG_TASK_DELAY_ACCT.
They are just two different interfaces for getting the same sched
information, so why make this change?

There must be some reason you don't want to enable
CONFIG_SCHEDSTATS? If so, please add it in the changelog.

My guess is it depends on DEBUG_KERNEL which is not what you
want? But I see no reason it should have that dependency, it just
exposes some stats, looks like can be just removed (and moved out
of Kconfig,debug of course).
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