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Sat, 25 May 2019 07:19:56 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id p63sm6795234pfb.70.2019.05.25.07.19.55 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sat, 25 May 2019 07:19:55 -0700 (PDT) Date: Sat, 25 May 2019 10:19:54 -0400 From: Joel Fernandes To: Steven Rostedt Subject: Re: [PATCH RFC 0/5] Remove some notrace RCU APIs Message-ID: <20190525141954.GA176647@google.com> References: <20190524234933.5133-1-joel@joelfernandes.org> <20190524232458.4bcf4eb4@gandalf.local.home> <20190525081444.GC197789@google.com> <20190525070826.16f76ee7@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190525070826.16f76ee7@gandalf.local.home> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: rcu@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, Lai Jiangshan , linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, Josh Triplett , Miguel Ojeda , Ingo Molnar , Mathieu Desnoyers , "Paul E. McKenney" , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sat, May 25, 2019 at 07:08:26AM -0400, Steven Rostedt wrote: > On Sat, 25 May 2019 04:14:44 -0400 > Joel Fernandes wrote: > > > > I guess the difference between the _raw_notrace and just _raw variants > > > is that _notrace ones do a rcu_check_sparse(). Don't we want to keep > > > that check? > > > > This is true. > > > > Since the users of _raw_notrace are very few, is it worth keeping this API > > just for sparse checking? The API naming is also confusing. I was expecting > > _raw_notrace to do fewer checks than _raw, instead of more. Honestly, I just > > want to nuke _raw_notrace as done in this series and later we can introduce a > > sparse checking version of _raw if need-be. The other option could be to > > always do sparse checking for _raw however that used to be the case and got > > changed in http://lists.infradead.org/pipermail/linux-afs/2016-July/001016.html > > What if we just rename _raw to _raw_nocheck, and _raw_notrace to _raw ? That would also mean changing 160 usages of _raw to _raw_nocheck in the kernel :-/. The tracing usage of _raw_notrace is only like 2 or 3 users. Can we just call rcu_check_sparse directly in the calling code for those and eliminate the APIs? I wonder what Paul thinks about the matter as well. thanks, Steven!