On 01/30/2019 02:44 PM, Peter Zijlstra wrote:
> On Wed, Jan 30, 2019 at 11:30:41AM -0800, Alexei Starovoitov wrote:
>> On Wed, Jan 30, 2019 at 11:15:30AM +0100, Peter Zijlstra wrote:
>>> On Tue, Jan 29, 2019 at 08:04:56PM -0800, Alexei Starovoitov wrote:
>>>> Lockdep warns about false positive:
>>> This is not a false positive, and you probably also need to use
>>> down_read_non_owner() to match this up_read_non_owner().
>>>
>>> {up,down}_read() and {up,down}_read_non_owner() are not only different
>>> in the lockdep annotation; there is also optimistic spin stuff that
>>> relies on 'owner' tracking.
>> Can you point out in the code the spin bit?
> Hurmph, looks like you're right. I got lost in that stuff again. I hate
> that rwsem code :/It is actually related to how the lockdep code track if a lock is acquired or released. It is not actually related to how the rwsem code work. > > Rewriting that all is on the todo list somewhere, but it's far down :/ > I am actually planning to rewrite it. Hopefully, I can send out the patch soon. Cheers, Longman
