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[103.168.172.200]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6f0de95f7a7sm78160046d6.13.2025.04.13.23.01.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Apr 2025 23:01:27 -0700 (PDT) Received: from phl-compute-03.internal (phl-compute-03.phl.internal [10.202.2.43]) by mailfauth.phl.internal (Postfix) with ESMTP id D3F181200066; Mon, 14 Apr 2025 02:01:26 -0400 (EDT) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-03.internal (MEProxy); Mon, 14 Apr 2025 02:01:26 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddvudeljeekucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdggtfgfnhhsuhgsshgtrhhisggv pdfurfetoffkrfgpnffqhgenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpih gvnhhtshculddquddttddmnecujfgurhephffvvefufffkofgjfhgggfestdekredtredt tdenucfhrhhomhepuehoqhhunhcuhfgvnhhguceosghoqhhunhdrfhgvnhhgsehgmhgrih hlrdgtohhmqeenucggtffrrghtthgvrhhnpeegleejiedthedvheeggfejveefjeejkefg veffieeujefhueeigfegueehgeeggfenucevlhhushhtvghrufhiiigvpedtnecurfgrrh grmhepmhgrihhlfhhrohhmpegsohhquhhnodhmvghsmhhtphgruhhthhhpvghrshhonhgr lhhithihqdeiledvgeehtdeigedqudejjeekheehhedvqdgsohhquhhnrdhfvghngheppe hgmhgrihhlrdgtohhmsehfihigmhgvrdhnrghmvgdpnhgspghrtghpthhtohepudelpdhm ohguvgepshhmthhpohhuthdprhgtphhtthhopehlvghithgrohesuggvsghirghnrdhorh hgpdhrtghpthhtohepphgvthgvrhiisehinhhfrhgruggvrggurdhorhhgpdhrtghpthht ohepmhhinhhgohesrhgvughhrghtrdgtohhmpdhrtghpthhtohepfihilhhlsehkvghrnh gvlhdrohhrghdprhgtphhtthhopehlohhnghhmrghnsehrvgguhhgrthdrtghomhdprhgt phhtthhopegrvghhsehmvghtrgdrtghomhdprhgtphhtthhopehlihhnuhigqdhkvghrnh gvlhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehnvghtuggvvhesvhhg vghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopegvughumhgriigvthesghhoohhglh gvrdgtohhm X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Mon, 14 Apr 2025 02:01:26 -0400 (EDT) From: Boqun Feng To: Breno Leitao , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long Cc: aeh@meta.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, edumazet@google.com, jhs@mojatatu.com, kernel-team@meta.com, Erik Lundgren , "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Uladzislau Rezki , rcu@vger.kernel.org, Boqun Feng Subject: [RFC PATCH 6/8] rcuscale: Allow rcu_scale_ops::get_gp_seq to be NULL Date: Sun, 13 Apr 2025 23:00:53 -0700 Message-ID: <20250414060055.341516-7-boqun.feng@gmail.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250414060055.341516-1-boqun.feng@gmail.com> References: <20250414060055.341516-1-boqun.feng@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Paul E. McKenney --- 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 0f3059b1b80d..d9bff4b1928b 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 =3D cur_ops->exp_completed() / 2; - } else { + } else if (cur_ops->get_gp_seq) { b_rcu_gp_test_started =3D cur_ops->get_gp_seq(); + } else { + b_rcu_gp_test_started =3D 0; } } =20 @@ -625,9 +627,11 @@ rcu_scale_writer(void *arg) if (gp_exp) { b_rcu_gp_test_finished =3D cur_ops->exp_completed() / 2; - } else { + } else if (cur_ops->get_gp_seq) { b_rcu_gp_test_finished =3D cur_ops->get_gp_seq(); + } else { + b_rcu_gp_test_finished =3D 0; } if (shutdown) { smp_mb(); /* Assign before wake. */ --=20 2.47.1