Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 20 Nov 2020 11:55:22 -0500
From:   Joel Fernandes <joel@joelfernandes.org>
To:     "Singh, Balbir" <bsingharora@gmail.com>
Cc:     Nishanth Aravamudan <naravamudan@digitalocean.com>,
        Julien Desfossez <jdesfossez@digitalocean.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Vineeth Pillai <viremana@linux.microsoft.com>,
        Aaron Lu <aaron.lwe@gmail.com>,
        Aubrey Li <aubrey.intel@gmail.com>, tglx@linutronix.de,
        linux-kernel@vger.kernel.org, mingo@kernel.org,
        torvalds@linux-foundation.org, fweisbec@gmail.com,
        keescook@chromium.org, kerrnel@google.com,
        Phil Auld <pauld@redhat.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>, vineeth@bitbyteword.org,
        Chen Yu <yu.c.chen@intel.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Agata Gruza <agata.gruza@intel.com>,
        Antonio Gomez Iglesias <antonio.gomez.iglesias@intel.com>,
        graf@amazon.com, konrad.wilk@oracle.com, dfaggioli@suse.com,
        pjt@google.com, rostedt@goodmis.org, derkling@google.com,
        benbjiang@tencent.com,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        James.Bottomley@hansenpartnership.com, OWeisse@umich.edu,
        Dhaval Giani <dhaval.giani@oracle.com>,
        Junaid Shahid <junaids@google.com>, jsbarnes@google.com,
        chris.hyser@oracle.com, Ben Segall <bsegall@google.com>,
        Josh Don <joshdon@google.com>, Hao Luo <haoluo@google.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Aubrey Li <aubrey.li@linux.intel.com>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Tim Chen <tim.c.chen@intel.com>
Subject: Re: [PATCH -tip 01/32] sched: Wrap rq::lock access
Message-ID: <20201120165522.GA1021337@google.com>
References: <20201117232003.3580179-1-joel@joelfernandes.org>
 <20201117232003.3580179-2-joel@joelfernandes.org>
 <1489211d-594c-d244-0111-8bd8a27fb945@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1489211d-594c-d244-0111-8bd8a27fb945@gmail.com>
Precedence: bulk

On Fri, Nov 20, 2020 at 10:31:39AM +1100, Singh, Balbir wrote:
> On 18/11/20 10:19 am, Joel Fernandes (Google) wrote:
> > From: Peter Zijlstra <peterz@infradead.org>
> > 
> > In preparation of playing games with rq->lock, abstract the thing
> > using an accessor.
> > 
> 
> Could you clarify games? I presume the intention is to redefine the scope
> of the lock based on whether core sched is enabled or not? I presume patch
> 4/32 has the details.

Your line wrapping broke, I fixed it.

That is in fact the game. By wrapping it, the nature of the locking is
dynamic based on whether core sched is enabled or not (both statically and
dynamically).

thanks,

 - Joel

 
> Balbir Singh