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McKenney" To: Joel Fernandes Cc: linux-kernel@vger.kernel.org, Frederic Weisbecker , Jonathan Corbet , Josh Triplett , kernel-team@android.com, Lai Jiangshan , linux-doc@vger.kernel.org, Mathieu Desnoyers , Mauro Carvalho Chehab , rcu@vger.kernel.org, Steven Rostedt , luto@kernel.org Subject: Re: [RFC v1 2/2] rcu/tree: Remove dynticks_nmi_nesting counter Message-ID: <20190829160946.GP4125@linux.ibm.com> Reply-To: paulmck@kernel.org References: <20190828202330.GS26530@linux.ibm.com> <20190828210525.GB75931@google.com> <20190828211904.GX26530@linux.ibm.com> <20190828214241.GD75931@google.com> <20190828220108.GC26530@linux.ibm.com> <20190828221444.GA100789@google.com> <20190828231247.GE26530@linux.ibm.com> <20190829015155.GB100789@google.com> <20190829034336.GD4125@linux.ibm.com> <20190829144355.GE63638@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190829144355.GE63638@google.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-29_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1034 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=818 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908290170 Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On Thu, Aug 29, 2019 at 10:43:55AM -0400, Joel Fernandes wrote: [ . . . ] > Paul, do we also nuke rcu_eqs_special_set()? Currently I don't see anyone > using it. And also remove the bottom most bit of dynticks? > > Also what happens if a TLB flush broadcast is needed? Do we IPI nohz or idle > CPUs are the moment? > > All of this was introduced in: > b8c17e6664c4 ("rcu: Maintain special bits at bottom of ->dynticks counter") Adding Andy Lutomirski on CC. Andy, is this going to be used in the near term, or should we just get rid of it? Thanx, Paul