From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Steve Wise" Subject: RE: Flush warning Date: Wed, 9 Aug 2017 11:38:49 -0500 Message-ID: <011601d3112d$fa305b70$ee911250$@opengridcomputing.com> References: <016301d30c86$e7034ae0$b509e0a0$@opengridcomputing.com> <9bc142de-b8ba-acb6-5ea1-2ccdbb578655@grimberg.me> <003401d30f91$c7e2a3f0$57a7ebd0$@opengridcomputing.com> <00ff01d3112b$94142350$bc3c69f0$@opengridcomputing.com> <20170809162749.GA4069@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170809162749.GA4069-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Content-Language: en-us Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: 'Jason Gunthorpe' Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, 'Sean Hefty' , 'Sagi Grimberg' , linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, 'Christoph Hellwig' List-Id: linux-rdma@vger.kernel.org > On Wed, Aug 09, 2017 at 11:21:38AM -0500, Steve Wise wrote: > > > > I don't know. I read the workqueue doc on WQ_MEM_RECLAIM, but I don't > know > > > how > > > to tell if iw_cm needs this or not. Can you give me an example of a workqueue > > > that _does_ need WQ_MEM_RECLAIM? I _think_ it means your workqueue is > > > required > > > to run something that would get triggered by the oom OS code, but I don't know > > > if that would include rdma CMs or not... > > > > Many of the workqueues in infiniband/core use WQ_MEM_RECLAIM: cma, iwcm, > mad, > > multicast, sa_query, and ucma. > > > > Hey Sean, do you have any insight into whether the CMA modules really need > > WQ_MEM_RECLAIM for their workqueues? > > > > Does anyone else know? > > Consider that the ib_core can be used to back storage. Ie consider a > situation where iSER/NFS/SRP needs to reconnect to respond to kernel > paging/reclaim. > > On the surface it seems reasonable to me that these are on a reclaim > path? > > Jason hmm. That seems reasonable. Then I would think the nvme_rdma would also need to be using a reclaim workqueue. Sagi, Do you think I should add a private workqueue with WQ_MEM_RECLAIM to nvme_rdma vs using the system_wq? nvme/target probably needs one also... Steve. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html