Re: [PATCH v3] sched/debug: Use sched_debug_lock to serialize use of cgroup_path[] only
From: Steven Rostedt
Date: Mon Apr 05 2021 - 11:59:24 EST
On Sun, 4 Apr 2021 21:27:00 -0400
Waiman Long <longman@xxxxxxxxxx> wrote:
> Thanks for the suggestion, but it also sound complicated.
It's not that complicated. Similar tricks have been used elsewhere in the
kernel.
>
> I think we can fix this lockup problem if we are willing to lose some
It's not a lockup problem, it's just a delay.
> information in case of contention. As you have suggested, a trylock will
> be used to acquire sched_debug_lock. If succeeded, all is good.
> Otherwise, a shorter stack buffer will be used for cgroup path. The path
> may be truncated in this case. If we detect that the full length of the
> buffer is used, we assume truncation and add, e.g. "...", to indicate
> there is more to the actual path.
>
> Do you think this is an acceptable comprise?
I guess that needs to be decided by those that use this information.
-- Steve