From mboxrd@z Thu Jan 1 00:00:00 1970 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 D81FA2236F0; Mon, 29 Dec 2025 19:10:56 +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=1767035456; cv=none; b=JHrY0DjcxjonXd3FDeE4CZF74+YsS+d3Dpp9nGIodiVWsvQofPuHMe+QcOmgoE9vQaYFZTHW0av2xVO9gYPJD2f0RXUl4fHPujuNJFFUK3DRcaFu1H8JSxN7EQz5D6ck0hcHlNhEeHXUsG+Jmew3qw9Kmmd3I4RPCcMmJbJ/B5I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767035456; c=relaxed/simple; bh=rgGdwE17c3qQE80WxxtNFlMUUyaNRfH3KQGS/shxEnQ=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=PbInUO8GV2FoKN5jo5W7htOyKwfUh34FUiFMi81lLgdSh3tFt3sv+Pu4P5htPnPvAoHO8FEVCenLeynPBkfmAsPUL2tjqs2poAsNnvEwmItKwvqSZNp93ZE4V7jrGK3JT8d4gKlijavgNU1OUO95RPupKn573pwLXil2L3OhWvg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uaNk8zEx; 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="uaNk8zEx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68CABC4CEF7; Mon, 29 Dec 2025 19:10:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767035456; bh=rgGdwE17c3qQE80WxxtNFlMUUyaNRfH3KQGS/shxEnQ=; h=Date:From:To:Cc:Subject:Reply-To:From; b=uaNk8zExCDSq0idpbqtia7W83w5q8USC1GKNzLvmeEZsB53BcW/fn7CaXc4xUc7Ml n6aI8T0UsYJgGMv4fc0cpCEy0b11L9djWeMd+BQ0kd2b0p3C0WBNh+uBi453rphiIO 82Yzt49tzE6m+9ept8H15mmBVbXcp75mqD2sdiEPCmlakIoxt2nIqzNv2my3WWXSoI R9wtxfY9hXPi+D1eA/VnBBrpDYh+k1psiz60iAirWTCj4VpNSlNBO+AWpLjCWsMNW+ EFUmI7L8A42Fw9uslHpTLiK/PmK4zeVuvNpyp6OSEpJoCACM36oxXjANd+bJWlx3Jx uF3rh8JsXfGzg== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id F35C9CE0C97; Mon, 29 Dec 2025 11:10:55 -0800 (PST) Date: Mon, 29 Dec 2025 11:10:55 -0800 From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org Subject: [PATCH v4 0/9] Implement RCU Tasks Trace in terms of SRCU for post-v4.19 Message-ID: Reply-To: paulmck@kernel.org Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hello! This v4 patch series re-implements RCU Tasks Trace in terms of SRCU-fast, reducing the size of the Linux-kernel RCU implementation by several hundred lines of code. The patches are as follows: 1. Re-implement RCU Tasks Trace in terms of SRCU-fast. 2. context_tracking: Remove rcu_task_trace_heavyweight_{enter,exit}(). 3. Clean up after the SRCU-fastification of RCU Tasks Trace. 4. Move rcu_tasks_trace_srcu_struct out of #ifdef CONFIG_TASKS_RCU_GENERIC. 5. Add noinstr-fast rcu_read_{,un}lock_tasks_trace() APIs. 6. Update Requirements.rst for RCU Tasks Trace. 7. Deprecate rcu_read_{,un}lock_trace(). 8. Create an rcu_tasks_trace_expedite_current() function. 9. Test rcu_tasks_trace_expedite_current(). Changes since v3: o Rebase onto v6.19-rc1. o Wait for arm64 per-CPU variable speedups to reach mainline. https://lore.kernel.org/all/a1e505e4-931b-45cf-8ca7-337442aa598e@paulmck-laptop/#r Changes since v2: o SRCU improvments not strictly related to RCU tasks trace have been moved out to a separate series. o Use the new DEFINE_SRCU_FAST(). https://lore.kernel.org/all/7fa58961-2dce-4e08-8174-1d1cc592210f@paulmck-laptop/ Changes since v1: o Consolidate RCU Tasks Trace cleanup patches per Alexei Starovoitov feedback. This explains the decrease from 34 patches in v1 to only 21 in this v2 series. o While consolidating, consolidate the noinstr-fast patches and the DEFINE_SRCU_FAST()/init_srcu_struct_fast() patches. o Upgrade comments per Peter Zijlstra feedback. o Extract Tiny SRCU bug fix into its own commit per Andrii Nakryiko feedback. o Switch srcu_expedite_current() from preempt_disable() to migrate_disable() for PREEMPT_RT kernels per Zqiang feedback. o Apply tags. https://lore.kernel.org/all/580ea2de-799a-4ddc-bde9-c16f3fb1e6e7@paulmck-laptop/ Thanx, Paul ------------------------------------------------------------------------ b/Documentation/RCU/Design/Requirements/Requirements.rst | 12 b/Documentation/admin-guide/kernel-parameters.txt | 15 b/include/linux/rcupdate.h | 31 b/include/linux/rcupdate_trace.h | 107 +- b/include/linux/sched.h | 1 b/init/init_task.c | 3 b/kernel/context_tracking.c | 20 b/kernel/fork.c | 3 b/kernel/rcu/Kconfig | 18 b/kernel/rcu/rcu.h | 9 b/kernel/rcu/rcuscale.c | 7 b/kernel/rcu/rcutorture.c | 2 b/kernel/rcu/tasks.h | 621 --------------- b/scripts/checkpatch.pl | 4 b/tools/testing/selftests/rcutorture/configs/rcu/TRACE01 | 1 b/tools/testing/selftests/rcutorture/configs/rcu/TRACE02 | 1 include/linux/rcupdate_trace.h | 81 + include/linux/sched.h | 5 kernel/rcu/Kconfig | 25 kernel/rcu/rcutorture.c | 1 kernel/rcu/tasks.h | 121 -- 21 files changed, 219 insertions(+), 869 deletions(-)