From patchwork Fri Oct 11 17:39:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 13832870 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B6CC31C9B97; Fri, 11 Oct 2024 17:39:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728668373; cv=none; b=uguEun9STXNTjAQhmkXPao6ZLWBy3OuqC4AmHGQoUT/l7ORyr17sEACR4hpzHqVlMIOiPV53Tj93s3L6Pwy5xVFkaWBnD43jmGjMDeek9T/+kFAua2EqBpczlJNLAXs58B31q8iC+QYSfbtvqGQ6jwpCA02l0tRGVyj3qqstcts= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728668373; c=relaxed/simple; bh=ShAY23PXWJnTwN9m3aELbGSryO452AQIXFVffiHUjJ8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=qJz9TsROkCFsVzCyPLFJ9Ctc0knsHok5Iyx+5fVAv1AJ2QTMlMTRVWfv8rOH9j9O8JQqAfmqSgl+V/ghrc0npzDtCYyvTrhy+Xhx8lt27V0A2rNUwWFQU/vLiTQy1KATml8eA7UnTgEX06Sfkc6zBVd4+E47D/WJvlQEwKotGRk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qZ2hdvVT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qZ2hdvVT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E0D5C4CEDF; Fri, 11 Oct 2024 17:39:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728668373; bh=ShAY23PXWJnTwN9m3aELbGSryO452AQIXFVffiHUjJ8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qZ2hdvVT0seSG7P9xAp+Nfp1Cy6Rc+ziKChMFejj4pIc0mrXe0g5jULUHzjt7mlPP rRQu1Ze3UPmPQ+Se3f27pjFL99b7v0K/yD63UbKadhzN0/BNM6buzq5kUXqEg/TJPw rdxgnSSTZYn11tlHhsYaQY7+D9wWKOs9NpCuMIzro+u6RWslj7KMZIgfzLgLmHm+i0 bhBfQiBc6Bn0iFHApB8WK3DfmTJWyPvQQBGIpXeXa3Pp1CtYpAlnJzljPvuPiu1+ff 4fz3hbFScFXgVVBfHdqH927XZnTNjX10qfVbbmVjV/1PKCpXiUUC15IBh26eyC09/e 5oTCbLg0JfanA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id B8907CE0FA0; Fri, 11 Oct 2024 10:39:32 -0700 (PDT) From: "Paul E. McKenney" To: frederic@kernel.org, rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, "Paul E. McKenney" , Alexei Starovoitov , Andrii Nakryiko , Peter Zijlstra , Kent Overstreet , bpf@vger.kernel.org Subject: [PATCH v2 rcu 12/13] refscale: Add srcu_read_lock_lite() support using "srcu-lite" Date: Fri, 11 Oct 2024 10:39:30 -0700 Message-Id: <20241011173931.2050422-12-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <3b82ac1a-8786-4a27-8eff-ecc67b50dfb6@paulmck-laptop> References: <3b82ac1a-8786-4a27-8eff-ecc67b50dfb6@paulmck-laptop> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This commit creates a new srcu-lite option for the refscale.scale_type module parameter that selects srcu_read_lock_lite() and srcu_read_unlock_lite(). Signed-off-by: Paul E. McKenney Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Kent Overstreet Cc: --- kernel/rcu/refscale.c | 51 +++++++++++++++++++++++++++++++++---------- 1 file changed, 40 insertions(+), 11 deletions(-) diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c index 0db9db73f57f2..09ee27ced2a78 100644 --- a/kernel/rcu/refscale.c +++ b/kernel/rcu/refscale.c @@ -212,6 +212,36 @@ static const struct ref_scale_ops srcu_ops = { .name = "srcu" }; +static void srcu_lite_ref_scale_read_section(const int nloops) +{ + int i; + int idx; + + for (i = nloops; i >= 0; i--) { + idx = srcu_read_lock_lite(srcu_ctlp); + srcu_read_unlock_lite(srcu_ctlp, idx); + } +} + +static void srcu_lite_ref_scale_delay_section(const int nloops, const int udl, const int ndl) +{ + int i; + int idx; + + for (i = nloops; i >= 0; i--) { + idx = srcu_read_lock_lite(srcu_ctlp); + un_delay(udl, ndl); + srcu_read_unlock_lite(srcu_ctlp, idx); + } +} + +static const struct ref_scale_ops srcu_lite_ops = { + .init = rcu_sync_scale_init, + .readsection = srcu_lite_ref_scale_read_section, + .delaysection = srcu_lite_ref_scale_delay_section, + .name = "srcu-lite" +}; + #ifdef CONFIG_TASKS_RCU // Definitions for RCU Tasks ref scale testing: Empty read markers. @@ -1082,27 +1112,26 @@ ref_scale_init(void) long i; int firsterr = 0; static const struct ref_scale_ops *scale_ops[] = { - &rcu_ops, &srcu_ops, RCU_TRACE_OPS RCU_TASKS_OPS &refcnt_ops, &rwlock_ops, - &rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, &clock_ops, &jiffies_ops, - &typesafe_ref_ops, &typesafe_lock_ops, &typesafe_seqlock_ops, + &rcu_ops, &srcu_ops, &srcu_lite_ops, RCU_TRACE_OPS RCU_TASKS_OPS + &refcnt_ops, &rwlock_ops, &rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, + &clock_ops, &jiffies_ops, &typesafe_ref_ops, &typesafe_lock_ops, + &typesafe_seqlock_ops, }; if (!torture_init_begin(scale_type, verbose)) return -EBUSY; for (i = 0; i < ARRAY_SIZE(scale_ops); i++) { - cur_ops = scale_ops[i]; - if (strcmp(scale_type, cur_ops->name) == 0) + cur_ops = scale_ops[i]; if (strcmp(scale_type, + cur_ops->name) == 0) break; } if (i == ARRAY_SIZE(scale_ops)) { - pr_alert("rcu-scale: invalid scale type: \"%s\"\n", scale_type); - pr_alert("rcu-scale types:"); - for (i = 0; i < ARRAY_SIZE(scale_ops); i++) + pr_alert("rcu-scale: invalid scale type: \"%s\"\n", + scale_type); pr_alert("rcu-scale types:"); for (i = 0; + i < ARRAY_SIZE(scale_ops); i++) pr_cont(" %s", scale_ops[i]->name); - pr_cont("\n"); - firsterr = -EINVAL; - cur_ops = NULL; + pr_cont("\n"); firsterr = -EINVAL; cur_ops = NULL; goto unwind; } if (cur_ops->init)