From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 577A9C433E9 for ; Wed, 6 Jan 2021 16:57:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C02523135 for ; Wed, 6 Jan 2021 16:57:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727855AbhAFQ4z (ORCPT ); Wed, 6 Jan 2021 11:56:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:56748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727347AbhAFQ4y (ORCPT ); Wed, 6 Jan 2021 11:56:54 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0316D23332; Wed, 6 Jan 2021 16:55:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1609952134; bh=4LG+A5nBqGrNwzad8okpBkoWV5G6uEL0A1Ds8zP3RBA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LXZ+CzMmed6fnWp09Rz3aoDV+dUpaRsnFn3vApW3Pxb3AeCeXVXHXR4H9mubuJ0l5 obc3ydVOCboEFFwhFliEX2+pHk2fu5zYt2z6tWPsVKOKMsGiDqsGCsfFemRucFWzSm XhE/Kie6sosMjEWxyDB4JkpgpzSUV+iBzmIjcx3OOQtt5Ug3wIqhxnogjngQ3Pybab vZhKI5BO/H92NEZ/C3Jx8a2HQjtjSgKz2J/XkY6I2UCbtIbRmd8w+WX5036IOduP0g crpfYAFBn5HatlnCMSGhyhZC03Ey9JRS+mkd4HdJqW5Pa8f7FCKb66lVL2n3uf+wnZ qS2722eZSV5MQ== From: paulmck@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 09/10] rcutorture: Add writer-side tests of polling grace-period API Date: Wed, 6 Jan 2021 08:55:30 -0800 Message-Id: <20210106165531.20697-9-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20210106165511.GA20555@paulmck-ThinkPad-P72> References: <20210106165511.GA20555@paulmck-ThinkPad-P72> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" This commit adds writer-side testing of the polling grace-period API. One test verifies that the polling API sees a grace period caused by some other mechanism. Another test verifies that using the polling API to wait for a grace period does not result in too-short grace periods. A third test verifies that the polling API does not report completion within a read-side critical section. A fourth and final test verifies that the polling API does report completion given an intervening grace period. Link: https://lore.kernel.org/rcu/20201112201547.GF3365678@moria.home.lan/ Reported-by: Kent Overstreet Signed-off-by: Paul E. McKenney --- kernel/rcu/rcutorture.c | 79 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 72 insertions(+), 7 deletions(-) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index bcea23c..78ba95d 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -85,6 +85,7 @@ torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives"); torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives"); +torture_param(bool, gp_poll, false, "Use polling GP wait primitives"); torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers"); @@ -183,9 +184,11 @@ static int rcu_torture_writer_state; #define RTWS_EXP_SYNC 4 #define RTWS_COND_GET 5 #define RTWS_COND_SYNC 6 -#define RTWS_SYNC 7 -#define RTWS_STUTTER 8 -#define RTWS_STOPPING 9 +#define RTWS_POLL_GET 7 +#define RTWS_POLL_WAIT 8 +#define RTWS_SYNC 9 +#define RTWS_STUTTER 10 +#define RTWS_STOPPING 11 static const char * const rcu_torture_writer_state_names[] = { "RTWS_FIXED_DELAY", "RTWS_DELAY", @@ -194,6 +197,8 @@ static const char * const rcu_torture_writer_state_names[] = { "RTWS_EXP_SYNC", "RTWS_COND_GET", "RTWS_COND_SYNC", + "RTWS_POLL_GET", + "RTWS_POLL_WAIT", "RTWS_SYNC", "RTWS_STUTTER", "RTWS_STOPPING", @@ -312,6 +317,8 @@ struct rcu_torture_ops { void (*sync)(void); void (*exp_sync)(void); unsigned long (*get_gp_state)(void); + unsigned long (*start_gp_poll)(void); + bool (*poll_gp_state)(unsigned long oldstate); void (*cond_sync)(unsigned long oldstate); call_rcu_func_t call; void (*cb_barrier)(void); @@ -570,6 +577,21 @@ static void srcu_torture_synchronize(void) synchronize_srcu(srcu_ctlp); } +static unsigned long srcu_torture_get_gp_state(void) +{ + return get_state_synchronize_srcu(srcu_ctlp); +} + +static unsigned long srcu_torture_start_gp_poll(void) +{ + return start_poll_synchronize_srcu(srcu_ctlp); +} + +static bool srcu_torture_poll_gp_state(unsigned long oldstate) +{ + return poll_state_synchronize_srcu(srcu_ctlp, oldstate); +} + static void srcu_torture_call(struct rcu_head *head, rcu_callback_t func) { @@ -601,6 +623,9 @@ static struct rcu_torture_ops srcu_ops = { .deferred_free = srcu_torture_deferred_free, .sync = srcu_torture_synchronize, .exp_sync = srcu_torture_synchronize_expedited, + .get_gp_state = srcu_torture_get_gp_state, + .start_gp_poll = srcu_torture_start_gp_poll, + .poll_gp_state = srcu_torture_poll_gp_state, .call = srcu_torture_call, .cb_barrier = srcu_torture_barrier, .stats = srcu_torture_stats, @@ -1027,18 +1052,20 @@ static int rcu_torture_writer(void *arg) { bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); + unsigned long cookie; int expediting = 0; unsigned long gp_snap; bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal; - bool gp_sync1 = gp_sync; + bool gp_poll1 = gp_poll, gp_sync1 = gp_sync; int i; + int idx; int oldnice = task_nice(current); struct rcu_torture *rp; struct rcu_torture *old_rp; static DEFINE_TORTURE_RANDOM(rand); bool stutter_waited; int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, - RTWS_COND_GET, RTWS_SYNC }; + RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC }; int nsynctypes = 0; VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); @@ -1048,8 +1075,8 @@ rcu_torture_writer(void *arg) torture_type, cur_ops->name); /* Initialize synctype[] array. If none set, take default. */ - if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1) - gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true; + if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_poll1 && !gp_sync1) + gp_cond1 = gp_exp1 = gp_normal1 = gp_poll1 = gp_sync1 = true; if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) { synctype[nsynctypes++] = RTWS_COND_GET; pr_info("%s: Testing conditional GPs.\n", __func__); @@ -1068,6 +1095,12 @@ rcu_torture_writer(void *arg) } else if (gp_normal && !cur_ops->deferred_free) { pr_alert("%s: gp_normal without primitives.\n", __func__); } + if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) { + synctype[nsynctypes++] = RTWS_POLL_GET; + pr_info("%s: Testing polling GPs.\n", __func__); + } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) { + pr_alert("%s: gp_poll without primitives.\n", __func__); + } if (gp_sync1 && cur_ops->sync) { synctype[nsynctypes++] = RTWS_SYNC; pr_info("%s: Testing normal GPs.\n", __func__); @@ -1107,6 +1140,18 @@ rcu_torture_writer(void *arg) atomic_inc(&rcu_torture_wcount[i]); WRITE_ONCE(old_rp->rtort_pipe_count, old_rp->rtort_pipe_count + 1); + if (cur_ops->get_gp_state && cur_ops->poll_gp_state) { + idx = cur_ops->readlock(); + cookie = cur_ops->get_gp_state(); + WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE && + cur_ops->poll_gp_state(cookie), + "%s: Cookie check 1 failed %s(%d) %lu->%lu\n", + __func__, + rcu_torture_writer_state_getname(), + rcu_torture_writer_state, + cookie, cur_ops->get_gp_state()); + cur_ops->readunlock(idx); + } switch (synctype[torture_random(&rand) % nsynctypes]) { case RTWS_DEF_FREE: rcu_torture_writer_state = RTWS_DEF_FREE; @@ -1128,6 +1173,18 @@ rcu_torture_writer(void *arg) cur_ops->cond_sync(gp_snap); rcu_torture_pipe_update(old_rp); break; + case RTWS_POLL_GET: + rcu_torture_writer_state = RTWS_POLL_GET; + gp_snap = cur_ops->start_gp_poll(); + rcu_torture_writer_state = RTWS_POLL_WAIT; + while (!cur_ops->poll_gp_state(gp_snap)) { + i = torture_random(&rand) % 16; + if (i != 0) + schedule_timeout_interruptible(i); + udelay(torture_random(&rand) % 1000); + } + rcu_torture_pipe_update(old_rp); + break; case RTWS_SYNC: rcu_torture_writer_state = RTWS_SYNC; cur_ops->sync(); @@ -1137,6 +1194,14 @@ rcu_torture_writer(void *arg) WARN_ON_ONCE(1); break; } + if (cur_ops->get_gp_state && cur_ops->poll_gp_state) + WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE && + !cur_ops->poll_gp_state(cookie), + "%s: Cookie check 2 failed %s(%d) %lu->%lu\n", + __func__, + rcu_torture_writer_state_getname(), + rcu_torture_writer_state, + cookie, cur_ops->get_gp_state()); } WRITE_ONCE(rcu_torture_current_version, rcu_torture_current_version + 1); -- 2.9.5