Re: [GIT PULL] Please pull proc and exec work for 5.7-rc1

Waiman Long
2020-04-04T02:11:28Z

On 4/3/20 9:30 PM, Linus Torvalds wrote:
> On Fri, Apr 3, 2020 at 4:23 PM Waiman Long <longman@redhat.com> wrote:
>> Alternatively, we could assert that only one reader can do the upgrade
>> and do a WARN_ON_ONCE() if multiple concurrent upgrade attempts is detected.
> Ack, that would be best.
>
> [ And since I'm not on mobile any more, and my html email got thrown
> out by the list, I'll just repeat that by "static choice" I mean "no
> runtime decisions or flags": code that needs the unfair behavior would
> use a special unfair function ]
>
> Linus
>
Got it.

So in term of priority, my current thinking is

upgrading unfair reader > unfair reader > reader/writer

A higher priority locker will block other lockers from acquiring the lock.

Thought?

Cheers,
Longman