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[94.245.46.61]) by smtp.gmail.com with ESMTPSA id t21sm1402941ljh.84.2021.05.03.12.34.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 May 2021 12:34:15 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 3 May 2021 21:34:13 +0200 To: "Paul E. McKenney" Cc: "Uladzislau Rezki (Sony)" , LKML , RCU , Michal Hocko , Andrew Morton , Daniel Axtens , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Peter Zijlstra , Thomas Gleixner , "Theodore Y . Ts'o" , Sebastian Andrzej Siewior , Oleksiy Avramchenko Subject: Re: [PATCH v1 5/5] kvfree_rcu: Fix comments according to current code Message-ID: <20210503193413.GA2421@pc638.lan> References: <20210428134422.1894-1-urezki@gmail.com> <20210428134422.1894-5-urezki@gmail.com> <20210503164723.GX975577@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210503164723.GX975577@paulmck-ThinkPad-P17-Gen-1> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Wed, Apr 28, 2021 at 03:44:22PM +0200, Uladzislau Rezki (Sony) wrote: > > We used to have an "emergency path" and comments related > > to it. According to current kvfree_rcu() design that path > > is not considered as emergency anymore. > > > > This patch rephrases and updates comments regarding this. > > > > Signed-off-by: Uladzislau Rezki (Sony) > > Queued as follows, thank you! Please check my usual wordsmithing to > make sure that I did not mess anything up. > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit 06c2113c4b1ce9ded69cd0ac4da9a00ed6be8834 > Author: Uladzislau Rezki (Sony) > Date: Wed Apr 28 15:44:22 2021 +0200 > > kvfree_rcu: Fix comments according to current code > > The kvfree_rcu() function now defers allocations in the common > case due to the fact that there is no lockless access to the > memory-allocator caches/pools. In addition, in CONFIG_PREEMPT_NONE=y > and in CONFIG_PREEMPT_VOLUNTARY=y kernels, there is no reliable way to > determine if spinlocks are held. As a result, allocation is deferred in > the common case, and the two-argument form of kvfree_rcu() thus uses the > "channel 3" queue through all the rcu_head structures. This channel > is called referred to as the emergency case in comments, and these > comments are now obsolete. > > This commit therefore updates these comments to reflect the new > common-case nature of such emergencies. > > Signed-off-by: Uladzislau Rezki (Sony) > Signed-off-by: Paul E. McKenney > Looks good to me. -- Vlad Rezki