From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [RFC PATCH v4 01/13] ktask: add documentation Date: Tue, 6 Nov 2018 20:51:54 +0000 Message-ID: <20181106205146.GB30490@mellanox.com> References: <20181105165558.11698-1-daniel.m.jordan@oracle.com> <20181105165558.11698-2-daniel.m.jordan@oracle.com> <20181106084911.GA22504@hirez.programming.kicks-ass.net> <20181106203411.pdce6tgs7dncwflh@ca-dmjordan1.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: Peter Zijlstra , "rjw@rjwysocki.net" , "linux-pm@vger.kernel.org" , "linux-mm@kvack.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "aarcange@redhat.com" , "aaron.lu@intel.com" , "akpm@linux-foundation.org" , "alex.williamson@redhat.com" , "bsd@redhat.com" , "darrick.wong@oracle.com" , "dave.hansen@linux.intel.com" , "jwadams@google.com" , "jiangshanlai@gmail.com" , "mhocko@kernel.org" , To: Daniel Jordan Return-path: In-Reply-To: <20181106203411.pdce6tgs7dncwflh@ca-dmjordan1.us.oracle.com> Content-Language: en-US Content-ID: <5D06AA0EB35F9848AAEE468B33AEEB0F@eurprd05.prod.outlook.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Tue, Nov 06, 2018 at 12:34:11PM -0800, Daniel Jordan wrote: > > What isn't clear is if this calling thread is waiting or not. Only do > > this inheritance trick if it is actually waiting on the work. If it is > > not, nobody cares. >=20 > The calling thread waits. Even if it didn't though, the inheritance tric= k > would still be desirable for timely completion of the job. Can you make lockdep aware that this is synchronous? ie if I do mutex_lock() ktask_run() mutex_lock() Can lockdep know that all the workers are running under that lock? I'm thinking particularly about rtnl_lock as a possible case, but there could also make some sense to hold the read side of the mm_sem or similar like the above. Jason