From nobody Tue Oct 7 15:01:46 2025 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 9684D21766A; Wed, 9 Jul 2025 10:43:25 +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=1752057805; cv=none; b=A8DCSuvgfmFlcC7p6jaRqfbDDYyoOChUru5o2te1AYgs9p0qDTy3ZBf21e9/QxzKqiZprsSJrRm47OLSkBi0YjaFQ5/RlbhQKdX+9DftGiZmb9XrQMCjjob6wcQ5oQ1Dr7aDxAniT3k9UQO6aZ1vOXNYONACi1tIFJXJsRPqOBM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752057805; c=relaxed/simple; bh=w0ultm8tcpppshfn+Iwj+Nx3B7+l8kg1Bdk2vOBcOKw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=oSguC0OKGQ7sn6ctc3dREFQWKT4U+vVZ/JcffYtn60msNoowohTegRsv9ShENYDYPD4+l17Rugd+nhlcxk+oUxfo0N7DW4jFgxuPRAclXDCgufjbNfV6J5aBU/4/QYMokQ7t0TMF8cKQVA157bQNQf5muUlO3U96sPME2t72mGM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cAvzB56b; 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="cAvzB56b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF3ACC4CEEF; Wed, 9 Jul 2025 10:43:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752057805; bh=w0ultm8tcpppshfn+Iwj+Nx3B7+l8kg1Bdk2vOBcOKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cAvzB56ba9+mAjp2vx8tfBU4/7w2/W3pVGv/jVH83Bp3MJLWWueYmAj6ycmxiMjwR UY1Z2gp6qUVNXKumWI5kh4osXnqp5XM42VgGbkM+khl3xVlVc9nPOocScUruh4Qz3z 6j2u2BJvJdfw+Uz++2l8VnLG6NX0UGOOjpRg0vndkq8Fc0hBDIs8rdCeH0pDijwd0u TBN82VTQyGPGr15xrzIxFTZNYXbYs8WqcNlIMSpogrXMD0oToMjOw0RwQjjoRPG20Q lrqmWR1sH9FZbex3i9ydeRpKX0juQbRrwvxtDutrCur8t+wMU7JTZQROALOF1jH4yP 06gBS6J1XAhtw== From: neeraj.upadhyay@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, paulmck@kernel.org, joelagnelf@nvidia.com, frederic@kernel.org, boqun.feng@gmail.com, urezki@gmail.com, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang1211@gmail.com, neeraj.iitr10@gmail.com, neeraj.upadhyay@amd.com, "Neeraj Upadhyay (AMD)" Subject: [PATCH rcu 09/15] rcutorture: Print number of RCU up/down readers and migrations Date: Wed, 9 Jul 2025 16:12:09 +0530 Message-Id: <20250709104215.15562-10-neeraj.upadhyay@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20250709104215.15562-1-neeraj.upadhyay@kernel.org> References: <20250709104215.15562-1-neeraj.upadhyay@kernel.org> 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" From: "Paul E. McKenney" This commit prints the number of RCU up/down readers and the number of such readers that migrated from one CPU to another, along with the rest of the periodic rcu_torture_stats_print() output. These statistics are currently used only by srcu_down_read{,_fast}() and srcu_up_read(,_fast)(). Signed-off-by: Paul E. McKenney Signed-off-by: Neeraj Upadhyay (AMD) --- kernel/rcu/rcutorture.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 10f3cc4861ee..3f644b1f5823 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -2450,9 +2450,11 @@ struct rcu_torture_one_read_state_updown { struct hrtimer rtorsu_hrt; bool rtorsu_inuse; ktime_t rtorsu_kt; + int rtorsu_cpu; unsigned long rtorsu_j; unsigned long rtorsu_ndowns; unsigned long rtorsu_nups; + unsigned long rtorsu_nmigrates; struct torture_random_state rtorsu_trs; struct rcu_torture_one_read_state rtorsu_rtors; }; @@ -2463,12 +2465,15 @@ static int rcu_torture_updown(void *arg); =20 static enum hrtimer_restart rcu_torture_updown_hrt(struct hrtimer *hrtp) { + int cpu =3D raw_smp_processor_id(); struct rcu_torture_one_read_state_updown *rtorsup; =20 rtorsup =3D container_of(hrtp, struct rcu_torture_one_read_state_updown, = rtorsu_hrt); rcu_torture_one_read_end(&rtorsup->rtorsu_rtors, &rtorsup->rtorsu_trs, -1= ); WARN_ONCE(rtorsup->rtorsu_nups >=3D rtorsup->rtorsu_ndowns, "%s: Up witho= ut matching down #%zu.\n", __func__, rtorsup - updownreaders); - rtorsup->rtorsu_nups++; + WRITE_ONCE(rtorsup->rtorsu_nups, rtorsup->rtorsu_nups + 1); + WRITE_ONCE(rtorsup->rtorsu_nmigrates, + rtorsup->rtorsu_nmigrates + (cpu !=3D rtorsup->rtorsu_cpu)); smp_store_release(&rtorsup->rtorsu_inuse, false); return HRTIMER_NORESTART; } @@ -2516,7 +2521,7 @@ static void rcu_torture_updown_cleanup(void) if (hrtimer_cancel(&rtorsup->rtorsu_hrt) || WARN_ON_ONCE(rtorsup->rtorsu= _inuse)) { rcu_torture_one_read_end(&rtorsup->rtorsu_rtors, &rtorsup->rtorsu_trs, = -1); WARN_ONCE(rtorsup->rtorsu_nups >=3D rtorsup->rtorsu_ndowns, "%s: Up wit= hout matching down #%zu.\n", __func__, rtorsup - updownreaders); - rtorsup->rtorsu_nups++; + WRITE_ONCE(rtorsup->rtorsu_nups, rtorsup->rtorsu_nups + 1); smp_store_release(&rtorsup->rtorsu_inuse, false); } =20 @@ -2534,13 +2539,14 @@ static void rcu_torture_updown_one(struct rcu_tortu= re_one_read_state_updown *rto =20 init_rcu_torture_one_read_state(&rtorsup->rtorsu_rtors, &rtorsup->rtorsu_= trs); rawidx =3D cur_ops->down_read(); - rtorsup->rtorsu_ndowns++; + WRITE_ONCE(rtorsup->rtorsu_ndowns, rtorsup->rtorsu_ndowns + 1); idx =3D (rawidx << RCUTORTURE_RDR_SHIFT_1) & RCUTORTURE_RDR_MASK_1; rtorsup->rtorsu_rtors.readstate =3D idx | RCUTORTURE_RDR_UPDOWN; rtorsup->rtorsu_rtors.rtrsp++; + rtorsup->rtorsu_cpu =3D raw_smp_processor_id(); if (!rcu_torture_one_read_start(&rtorsup->rtorsu_rtors, &rtorsup->rtorsu_= trs, -1)) { WARN_ONCE(rtorsup->rtorsu_nups >=3D rtorsup->rtorsu_ndowns, "%s: Up with= out matching down #%zu.\n", __func__, rtorsup - updownreaders); - rtorsup->rtorsu_nups++; + WRITE_ONCE(rtorsup->rtorsu_nups, rtorsup->rtorsu_nups + 1); schedule_timeout_idle(HZ); return; } @@ -2649,6 +2655,10 @@ rcu_torture_stats_print(void) long pipesummary[RCU_TORTURE_PIPE_LEN + 1] =3D { 0 }; long batchsummary[RCU_TORTURE_PIPE_LEN + 1] =3D { 0 }; long n_gpwraps =3D 0; + unsigned long ndowns =3D 0; + unsigned long nunexpired =3D 0; + unsigned long nmigrates =3D 0; + unsigned long nups =3D 0; struct rcu_torture *rtcp; static unsigned long rtcv_snap =3D ULONG_MAX; static bool splatted; @@ -2662,10 +2672,18 @@ rcu_torture_stats_print(void) if (cur_ops->get_gpwrap_count) n_gpwraps +=3D cur_ops->get_gpwrap_count(cpu); } + if (updownreaders) { + for (i =3D 0; i < n_up_down; i++) { + ndowns +=3D READ_ONCE(updownreaders[i].rtorsu_ndowns); + nups +=3D READ_ONCE(updownreaders[i].rtorsu_nups); + nunexpired +=3D READ_ONCE(updownreaders[i].rtorsu_inuse); + nmigrates +=3D READ_ONCE(updownreaders[i].rtorsu_nmigrates); + } + } for (i =3D RCU_TORTURE_PIPE_LEN; i >=3D 0; i--) { if (pipesummary[i] !=3D 0) break; - } + } // The value of variable "i" is used later, so don't clobber it! =20 pr_alert("%s%s ", torture_type, TORTURE_FLAG); rtcp =3D rcu_access_pointer(rcu_torture_current); @@ -2686,6 +2704,8 @@ rcu_torture_stats_print(void) n_rcu_torture_boost_failure, n_rcu_torture_boosts, atomic_long_read(&n_rcu_torture_timers)); + if (updownreaders) + pr_cont("ndowns: %lu nups: %lu nhrt: %lu nmigrates: %lu ", ndowns, nups,= nunexpired, nmigrates); torture_onoff_stats(); pr_cont("barrier: %ld/%ld:%ld ", data_race(n_barrier_successes), --=20 2.40.1