Re: [PATCH v3 3/5] locking/qspinlock: Introduce CNA into the slow path of qspinlock

[Alex Kogan]

>>  *    mcs_node
>>  *   +--------+      +----+         +----+
>>  *   | next   | ---> |next| -> ...  |next| -> NULL  [Main queue]
>>  *   | locked | -+   +----+         +----+
>>  *   +--------+  |
>>  *               |   +---------+         +----+
>>  *               +-> |mcs::next| -> ...  |next| -> NULL     [Secondary queue]
>> *                   |cna::tail| -+      +----+
>>  *                   +---------+  |        ^
>> *                                +--------+
>>  *
>>  * N.B. locked = 1 if secondary queue is absent.
>>  */


I would change mcs_node to cna_node, next to mcs::next and locked to mcs::locked
in the very first node. Other than that, this is great. Thanks, Peter and Longman!

I should probably stick this graphic in the comment at the top of the file, 
instead of a comment to find_successor() (or whatever this function ends up 
being called).

â Alex