There may be a bug of scan loop condition.

[CxdInitial]

Hey @DolevAdas , I have read the dequeue method, but there is one thing that confused me a lot. See the scan loop condition below:

Jiffy/MpScQueue.h

Line 172 in 82cb6fb

for (unsigned int scanHead = scanHeadOfQueue->head; ( scanHeadOfQueue != tempHeadOfQueue || scanHead < (tempHead-1) && n->is_set.load(std::memory_order_acquire) == 0); scanHead++)

I think it should be:
( (scanHeadOfQueue != tempHeadOfQueue || scanHead < (tempHead-1)) && n->is_set.load(std::memory_order_acquire) == 0)

The original scan loop condition makes the loop continue to run even if n->is_set.load(std::memory_order_acquire) != 0.

[planetis-m]

It's actually correct, this is the double scan loop and it's described both in the paper and the youtube presentation.