From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [RFC workqueue/driver-core PATCH 1/5] workqueue: Provide queue_work_near to queue work near a given NUMA node Date: Tue, 2 Oct 2018 10:41:16 -0700 Message-ID: <20181002174116.GG270328@devbig004.ftw2.facebook.com> References: <20180926214433.13512.30289.stgit@localhost.localdomain> <20180926215138.13512.33146.stgit@localhost.localdomain> <20180926215307.GA270328@devbig004.ftw2.facebook.com> <9b002bbb-3e6d-9e99-d8f9-36df4306093e@linux.intel.com> <20180926220957.GB270328@devbig004.ftw2.facebook.com> <20181001160142.GE270328@devbig004.ftw2.facebook.com> <4eebc017-23a2-a26e-095c-66433061a141@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <4eebc017-23a2-a26e-095c-66433061a141-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: Alexander Duyck Cc: len.brown-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, jiangshanlai-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, zwisler-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, pavel-+ZI9xUNit7I@public.gmane.org, rafael-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org List-Id: linux-pm@vger.kernel.org Hello, On Mon, Oct 01, 2018 at 02:54:39PM -0700, Alexander Duyck wrote: > >It might be better to leave queue_work_on() to be used for per-cpu > >workqueues and introduce queue_work_near() as you suggseted. I just > >don't want it to duplicate the node selection code in it. Would that > >work? > > So if I understand what you are saying correctly we default to > round-robin on a given node has no CPUs attached to it. I could > probably work with that if that is the default behavior instead of > adding much of the complexity I already have. Yeah, it's all in wq_select_unbound_cpu(). Right now, if the requested cpu isn't in wq_unbound_cpumask, it falls back to dumb round-robin. We can probably do better there and find the nearest node considering topology. > The question I have then is what should I do about workqueues that > aren't WQ_UNBOUND if they attempt to use queue_work_near? In that Hmm... yeah, let's just use queue_work_on() for now. We can sort it out later and users could already do that anyway. Thanks. -- tejun