Re: [PATCH v2 0/4] task: Making tasks on the runqueue rcu protected

[Eric W. Biederman]

Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes:

> On Sat, Sep 14, 2019 at 5:30 AM Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
>>
>> I have reworked these patches one more time to make it clear that the
>> first 3 patches only fix task_struct so that it experiences a rcu grace
>> period after it leaves the runqueue for the last time.
>
> I remain a fan of these patches, and the added comment on the last one
> is I think a sufficient clarification of the issue.
>
> But it's patch 3 that makes me go "yeah, this is the right approach",
> because it just removes subtle code in favor of something that is
> understandable.
>
> Yes, most of the lines removed may be comments, and so it doesn't
> actually remove a lot of _code_, but I think the comments are a result
> of just how subtle and fragile our current approach is, and the new
> model not needing them as much is I think a real issue (rather than
> just Eric being less verbose in the new comments and removing lines of
> code that way).

In fact the comments I add are orthogonal to the comments I removed.
My last patch stands on it's own.  It can be applied with or without the
rest.   I just needed to know which of the ordinary rcu guarantees were
or were not present in the code.

> Can anybody see anything wrong with the series? Because I'd love to
> have it for 5.4,

Peter,

I am more than happy for these to come through your tree.  However
if this is one thing to many I will be happy to send Linus a pull
request myself early next week.

Eric