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[46.139.12.213]) by smtp.gmail.com with ESMTPSA id g10sm33326723wrq.2.2019.04.12.00.09.06 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 12 Apr 2019 00:09:06 -0700 (PDT) Date: Fri, 12 Apr 2019 09:09:04 +0200 From: Ingo Molnar To: Peter Zijlstra Cc: Waiman Long , Ingo Molnar , Will Deacon , Thomas Gleixner , linux-kernel@vger.kernel.org, x86@kernel.org, Davidlohr Bueso , Linus Torvalds , Tim Chen , huang ying Subject: Re: [PATCH-tip v3 02/14] locking/rwsem: Make owner available even if !CONFIG_RWSEM_SPIN_ON_OWNER Message-ID: <20190412070904.GA45214@gmail.com> References: <20190410184231.6748-1-longman@redhat.com> <20190410184231.6748-3-longman@redhat.com> <20190411081224.GB4038@hirez.programming.kicks-ass.net> <29aca54a-536e-6e46-7e18-658914c34548@redhat.com> <20190412070209.GC129493@gmail.com> <20190412070545.GF11158@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190412070545.GF11158@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Peter Zijlstra wrote: > On Fri, Apr 12, 2019 at 09:02:09AM +0200, Ingo Molnar wrote: > > > > * Waiman Long wrote: > > > > > On 04/11/2019 04:12 AM, Peter Zijlstra wrote: > > > > On Wed, Apr 10, 2019 at 02:42:19PM -0400, Waiman Long wrote: > > > >> The owner field in the rw_semaphore structure is used primarily for > > > >> optimistic spinning. However, identifying the rwsem owner can also be > > > >> helpful in debugging as well as tracing locking related issues when > > > >> analyzing crash dump. The owner field may also store state information > > > >> that can be important to the operation of the rwsem. > > > >> > > > >> So the owner field is now made a permanent member of the rw_semaphore > > > >> structure irrespective of CONFIG_RWSEM_SPIN_ON_OWNER. > > > > sem->owner is still initialized under CONFIG_RWSEM_SPIN_ON_OWNER. > > > > > > Oh, you are right. I missed that part. I will fix it in the next version. > > > > Could you please post the next series against tip:WIP.locking/core, which > > is already being dogfood-ed in -tip and which I'm running on my desktop? > > I'll backmerge any fixes as needed/requested. > > Urgh, please no, that's going to be hell to review :/ Ok - full patches then. I'll handle the fallout. Thanks, Ingo