From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 73154221DB6; Tue, 2 Jun 2026 21:04:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780434242; cv=none; b=IQQYCOnKCUXcAtPHqyiHbXOO6Xpt7FzuZQH0eoYUm73uCepLvjjSzKqp3rHjsE4NyOkM/m/uPJandfHt80cuWKrpqsr8TEmjCKzgpBhcdqXu8HTJIh03P0ONcMBFRkwKbem9qUdPfxcrK2sL5iKwz4HA8mz0IbNmRDFozKtcoM0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780434242; c=relaxed/simple; bh=xcBwUqenQnYMfSBWCxuZu0/kzGfDaLbnZtYKX98y8zk=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ZA8UVlY/E8lTkdGxRJCpYK8mAAH+D5yAjUo4iiGtHtKn/wvHMLhLrZH6ELALsNjvMUxxELhZBreMj9NaSxuJdZKKHEL+OlReFSP2+qpBYkso/hyWwmafiIipcuctagUqKRSYF6T04c6sU69KhvityHcMN494L0OIISkGj3tvgmE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=URBRQO8E; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="URBRQO8E" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 544E51F00893; Tue, 2 Jun 2026 21:04:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780434241; bh=szrWBKhghiac2i2mueK/YjJu1FK82B5hSpdAwSlajBM=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=URBRQO8EBqqlHB/KHgDkXH5tmEouzPHMlK1s0wDdHL+bZ3gBuynAz+fso8Al8Jrj/ 9JQDn+55i4u1Z3eVPrHvnULBNeLDirvQ25E3iDMU+y6qmdfmrr8C8T+UcDLIr+mCO+ 0FEni1K10C+s+N+NJYUKd9Kxqk6Sp5Lvgkfwf/qPbSA+Jp9Kw9qancwOhtlaamVQDz 5ldsm636C9d6gkqy4Dnp/z7VGOIK09alUM8om2KAkTVIbDQTL9pwIi5SuexN4HFTki s96CuKvrux8DwF2d4l9PQDYp/KYZM3zd1Aatv3mJziyjCBU9o2dg6w02HwSlkI5Ckx a4nUS34yeqC0g== Date: Tue, 2 Jun 2026 14:03:59 -0700 From: Jakub Kicinski To: "D. Wythe" Cc: "David S. Miller" , Dust Li , Eric Dumazet , Paolo Abeni , Sidraya Jayagond , Wenjia Zhang , Mahanta Jambigi , Simon Horman , Tony Lu , Wen Gu , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, oliver.yang@linux.alibaba.com, pasic@linux.ibm.com Subject: Re: [PATCH net-next 0/2] net/smc: transition to RDMA core CQ pooling Message-ID: <20260602140359.3b97d180@kernel.org> In-Reply-To: <20260528084819.6059-1-alibuda@linux.alibaba.com> References: <20260528084819.6059-1-alibuda@linux.alibaba.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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/20260528084819.6059-2-alibuda@linux.alibaba.com Are these legit? Either way - would be good to get some reviews here from (ohter) SMC maintainers.