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[103.168.172.200]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4a779e910c8sm55291021cf.71.2025.06.24.20.11.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Jun 2025 20:11:33 -0700 (PDT) Received: from phl-compute-05.internal (phl-compute-05.phl.internal [10.202.2.45]) by mailfauth.phl.internal (Postfix) with ESMTP id 8C62AF40066; Tue, 24 Jun 2025 23:11:32 -0400 (EDT) Received: from phl-mailfrontend-02 ([10.202.2.163]) by phl-compute-05.internal (MEProxy); Tue, 24 Jun 2025 23:11:32 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtddvgddvudeihecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpuffrtefokffrpgfnqfghnecuuegr ihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjug hrpefhvfevufffkffojghfggfgsedtkeertdertddtnecuhfhrohhmpeeuohhquhhnucfh vghnghcuoegsohhquhhnrdhfvghnghesghhmrghilhdrtghomheqnecuggftrfgrthhtvg hrnhepgeeljeeitdehvdehgefgjeevfeejjeekgfevffeiueejhfeuiefggeeuheeggefg necuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepsghoqh hunhdomhgvshhmthhprghuthhhphgvrhhsohhnrghlihhthidqieelvdeghedtieegqddu jeejkeehheehvddqsghoqhhunhdrfhgvnhhgpeepghhmrghilhdrtghomhesfhhigihmvg drnhgrmhgvpdhnsggprhgtphhtthhopedviedpmhhouggvpehsmhhtphhouhhtpdhrtghp thhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtg hpthhtoheprhgtuhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehlkhhm mheslhhishhtshdrlhhinhhugidruggvvhdprhgtphhtthhopehpvghtvghriiesihhnfh hrrgguvggrugdrohhrghdprhgtphhtthhopehmihhnghhosehkvghrnhgvlhdrohhrghdp rhgtphhtthhopeifihhllheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepsghoqhhunh drfhgvnhhgsehgmhgrihhlrdgtohhmpdhrtghpthhtoheplhhonhhgmhgrnhesrhgvughh rghtrdgtohhmpdhrtghpthhtohepuggrvhgvsehsthhgohhlrggsshdrnhgvth X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 24 Jun 2025 23:11:32 -0400 (EDT) From: Boqun Feng To: linux-kernel@vger.kernel.org, rcu@vger.kernel.org, lkmm@lists.linux.dev Cc: Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng , Waiman Long , Davidlohr Bueso , "Paul E. McKenney" , Josh Triplett , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Breno Leitao , aeh@meta.com, netdev@vger.kernel.org, edumazet@google.com, jhs@mojatatu.com, kernel-team@meta.com, Erik Lundgren Subject: [PATCH 6/8] rcuscale: Allow rcu_scale_ops::get_gp_seq to be NULL Date: Tue, 24 Jun 2025 20:10:59 -0700 Message-Id: <20250625031101.12555-7-boqun.feng@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20250625031101.12555-1-boqun.feng@gmail.com> References: <20250625031101.12555-1-boqun.feng@gmail.com> Precedence: bulk X-Mailing-List: lkmm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit For synchronization mechanisms similar to RCU, there could be no "grace period" concept (e.g. hazard pointers), therefore allow rcu_scale_ops::get_gp_seq to be a NULL pointer for these cases, and simply treat started and finished grace period as 0. Signed-off-by: Boqun Feng --- kernel/rcu/rcuscale.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index b521d0455992..45413a73d61e 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -568,8 +568,10 @@ rcu_scale_writer(void *arg) if (gp_exp) { b_rcu_gp_test_started = cur_ops->exp_completed() / 2; - } else { + } else if (cur_ops->get_gp_seq) { b_rcu_gp_test_started = cur_ops->get_gp_seq(); + } else { + b_rcu_gp_test_started = 0; } } @@ -625,9 +627,11 @@ rcu_scale_writer(void *arg) if (gp_exp) { b_rcu_gp_test_finished = cur_ops->exp_completed() / 2; - } else { + } else if (cur_ops->get_gp_seq) { b_rcu_gp_test_finished = cur_ops->get_gp_seq(); + } else { + b_rcu_gp_test_finished = 0; } if (shutdown) { smp_mb(); /* Assign before wake. */ -- 2.39.5 (Apple Git-154)