From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Steve Wise" Subject: RE: Flush warning Date: Mon, 14 Aug 2017 12:21:40 -0500 Message-ID: <00be01d31521$cb237900$616a6b00$@opengridcomputing.com> References: <016301d30c86$e7034ae0$b509e0a0$@opengridcomputing.com> <9bc142de-b8ba-acb6-5ea1-2ccdbb578655@grimberg.me> <003401d30f91$c7e2a3f0$57a7ebd0$@opengridcomputing.com> <00ff01d3112b$94142350$bc3c69f0$@opengridcomputing.com> <20170809162749.GA4069@obsidianresearch.com> <011601d3112d$fa305b70$ee911250$@opengridcomputing.com> <20170813064651.GR24282@mtr-leonro.local> <90ada4f5-d6a1-2b93-5164-c593955c20cf@grimberg.me> <20170813103359.GW24282@mtr-leonro.local> <3d9cca62-4612-53dc-776c-3aeb2df58365@dev.mellanox.co.il> <1828884A29C6694DAF28B7E6B8A82373AB17595A@ORSMSX109.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1828884A29C6694DAF28B7E6B8A82373AB17595A-P5GAC/sN6hkd3b2yrw5b5LfspsVTdybXVpNB7YpNyf8@public.gmane.org> Content-Language: en-us Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "'Hefty, Sean'" , 'Hal Rosenstock' , 'Leon Romanovsky' , 'Sagi Grimberg' , 'Hal Rosenstock' Cc: 'Jason Gunthorpe' , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, 'Christoph Hellwig' List-Id: linux-rdma@vger.kernel.org > > >>> The workqueue which frees the memory and doesn't allocate memory > > >>> during execution is supposed to be marked as WQ_MEM_RECLAIM. This > > >>> flag will cause to priority increase for such workqueue during low > > memory conditions. > > >> > > >> Which to my understanding means that CM workqueue should not use it > > >> as on each CM connect, by definition the ULP allocates memory (qp, > > cq etc). > > > > > > From my understanding too. > > > That workqueue was introduced in 2005, in a977049dacde ("[PATCH] IB: > > > Add the kernel CM implementation"), it is not clear if it was > > > intentionally. > > > > > > Hal, > > > do you remember the rationale there? > > > > Sean is best to respond to this. > > I believe the work queue was to avoid potential deadlocks that could arise from > using the MAD work queue. The original submission did not mark the work queue > with WQ_MEM_RECLAIM. I do not know when that change was added. By the way, the queue I'm actually having the problem with is in the iwcm, not the ibcm. I think we should remove WQ_MEM_RECLAIM from all the CM queues because I agree now that ulps potentially can/will allocate memory in the contect of these workqueues... -- 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