From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck 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 11:23:26 -0700 Message-ID: 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> <20181002174116.GG270328@devbig004.ftw2.facebook.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181002174116.GG270328-LpCCV3molIbIZ9tKgghJQw2O0Ztt9esIQQ4Iyu8u01E@public.gmane.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: Tejun Heo 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 On 10/2/2018 10:41 AM, Tejun Heo wrote: > 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. Well if we could get wq_select_unbound_cpu doing the right thing based on node topology that would be most of my work solved right there. Basically I could just pass WQ_CPU_UNBOUND with the correct node and it would take care of getting to the right CPU. >> 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. So are you saying I should just return an error for now if somebody tries to use something other than an unbound workqueue with queue_work_near, and expect everyone else to just use queue_work_on for the other workqueue types? Thanks. - Alex