From patchwork Wed Nov 6 16:02:21 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frederic Weisbecker X-Patchwork-Id: 13865139 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 7F7022064F5; Wed, 6 Nov 2024 16:02:41 +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=1730908961; cv=none; b=K1YEphkw6kf7qycwP3bB1lFwHjQVSiSoeqx/vtNFOOFroC+rhIY7if4LoL1xlh5O6pJVvHYwyjuvK1MpJRGCkYYi1zNFQ59SB9oKeO2W+qxYLNOZt3zO1//BiYuOjqPMSlVxE45taSLF9lnockNqtPO2PpaawIh/m+0OV1U8DG8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730908961; c=relaxed/simple; bh=4glDQSNUoXiax4XF8AjgBBQOPX1MeTdEr5B6E0keNH8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JFFBiggH5dLSCE+8x/FeQ9UfT6N43PkrF4L0PtQHsX3wEm4Z4GUQp0RrtO90S33qXO4lgiexp99YfySgyDKOolpyWLNGRF/T1u0gJzRbB2jjBwXFfEdYX78MLMJI7vF5y779/f+RirIyb3WUsTmY7I2nUwk7aObowfzo+dYbe+U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FXLpXb1J; 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="FXLpXb1J" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE061C4CED4; Wed, 6 Nov 2024 16:02:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730908961; bh=4glDQSNUoXiax4XF8AjgBBQOPX1MeTdEr5B6E0keNH8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FXLpXb1J6rVW/SuU/Gqadi2jhe22nOaPSsoC+PTIlHtR5nBDiY0G5GOYyPWta6RXo S7cEWf89VH/aDQzPKRzjywAUo+YZ1l2nJOu5qhu52HYB3FN/nHcSmnZUrwYh9nx6ZN obqGLnYSCsaiKRZV9PxwXneMgPMv/KsSJKGAC+RSSjdenkSCOoqzLz1bteX4vnQN3I cGfiHRKwaYqd4DqTV1y5AJH2RxZoXLl/U1Kcghz46wyt0iCw9PlqSH1Z+QAZQLXgLM +rL231KJC5usVG9EwX+P/RWI6b8Uu44gUMCOPUPUOrmnO2E1KZ00WNEzCrswJVlvak YqRbLkx8NNIzA== From: Frederic Weisbecker To: LKML Cc: "Paul E. McKenney" , Boqun Feng , Joel Fernandes , Josh Triplett , Lai Jiangshan , Mathieu Desnoyers , Neeraj Upadhyay , Steven Rostedt , Uladzislau Rezki , Zqiang , rcu , Frederic Weisbecker Subject: [PATCH 4/6] rcutorture: Avoid printing cpu=-1 for no-fault RCU boost failure Date: Wed, 6 Nov 2024 17:02:21 +0100 Message-ID: <20241106160223.42119-5-frederic@kernel.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20241106160223.42119-1-frederic@kernel.org> References: <20241106160223.42119-1-frederic@kernel.org> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: "Paul E. McKenney" If a CPU runs throughout the stalled grace period without passing through a quiescent state, RCU priority boosting cannot help. The rcu_torture_boost_failed() function therefore prints a message flagging the first such CPU. However, if the stall was instead due to (for example) RCU's grace-period kthread being starved of CPU, there will be no such CPU, causing rcu_check_boost_fail() to instead pass back -1 through its cpup CPU-pointer parameter. Therefore, the current message complains about a mythical CPU -1. This commit therefore checks for this situation, and notes that all CPUs have passed through a quiescent state. Signed-off-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker --- kernel/rcu/rcutorture.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index bb75dbf5c800..e92fa97fc76f 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1059,8 +1059,13 @@ static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *star // At most one persisted message per boost test. j = jiffies; lp = READ_ONCE(last_persist); - if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp) - pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); + if (time_after(j, lp + mininterval) && + cmpxchg(&last_persist, lp, j) == lp) { + if (cpu < 0) + pr_info("Boost inversion persisted: QS from all CPUs\n"); + else + pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); + } return false; // passed on a technicality } VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");