Subject: Re: [PATCH net-next 0/2] net/smc: transition to RDMA core CQ pooling

From: Jakub Kicinski <[email-masked]>
Date: Tue, 2 Jun 2026 14:03:59 -0700

On Thu, 28 May 2026 16:48:17 +0800 D. Wythe wrote:
> This series transitions SMC-R completion handling to RDMA core CQ pooling
> via the ib_cqe API. The new completion model improves scalability by
> allowing per-link completion processing across multiple cores and enables
> DIM-based interrupt moderation.
> 
> As a side effect, the increased concurrency can amplify contention for TX
> slots on the shared wait queue. Patch 2 addresses this by switching TX slot
> allocation from non-exclusive wait_event() to prepare_to_wait_exclusive(),
> which avoids thundering-herd wakeups under contention.
> 
> Patch 1 replaces the global per-device CQ and manual tasklet polling model
> with RDMA core CQ pooling.
> Patch 2 reduces TX slot contention by using exclusive wait queue entries
> during allocation.

Sashiko reports a couple of issues on patch 1:
https://sashiko.dev/#/patchset/[email-masked]
Are these legit?

Either way - would be good to get some reviews here from (ohter) SMC
maintainers.