From patchwork Fri Apr 24 13:56:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Valentin Schneider X-Patchwork-Id: 11507935 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 47CF892A for ; Fri, 24 Apr 2020 13:58:34 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2144D20776 for ; Fri, 24 Apr 2020 13:58:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="kVU7nLse" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2144D20776 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=YbMpwTUQGHWDEJa4Sp2NKTUPlwcPAiQ8NqfkXe29S8Q=; b=kVU7nLseAAjbu8 Q92vAB0f/UNUJ9uxm4f7tkvMSg6sfGjSJBG8u+0s2q9p+lFmbCLalZ1/+vHzZxR6oyk/t12Fowssf BaRBFtxH/etS53uOkJvwkiA0pku0sjCIrUKTUs1eaAdZocpLIcl10oP3idbA5bWyai0rBKqj7u1Nb //tNk/SUrqwiRYJWa5mx42ZOMvNkZoXhlIojaG8dKM60i92ifXDQ4wEBznYsmXDPDf/D/NgDRBmwb uexs11RpEOt3Ec2HjqoZHXTWuy9+gYVvA5DxYJHNfaugLa39mbsaj4YvlUZIuoqWSCf9qDlqIfsVR 7HCiOyV4tNG1c2BuE53Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRyqd-00070X-HG; Fri, 24 Apr 2020 13:58:31 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRyqO-0006mb-Kw for linux-arm-kernel@lists.infradead.org; Fri, 24 Apr 2020 13:58:19 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 63408C14; Fri, 24 Apr 2020 06:58:14 -0700 (PDT) Received: from e113632-lin.cambridge.arm.com (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6389A3F68F; Fri, 24 Apr 2020 06:58:13 -0700 (PDT) From: Valentin Schneider To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/2] firmware/psci: Make PSCI checker not bother with parking Date: Fri, 24 Apr 2020 14:56:56 +0100 Message-Id: <20200424135657.32519-2-valentin.schneider@arm.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20200424135657.32519-1-valentin.schneider@arm.com> References: <20200424135657.32519-1-valentin.schneider@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200424_065816_772693_E943E33D X-CRM114-Status: GOOD ( 12.71 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Zijlstra , Lorenzo Pieralisi , Sudeep Holla Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org kthread_stop() unconditionally calls kthread_unpark(). For kthreads with KTHREAD_IS_PER_CPU, this leads to waiting for wait_task_inactive(TASK_PARKED) before re-binding them. This is required mainly for smpboot threads, as they are parked before their respective CPU comes online which causes their affinity mask to be reset. For users of kthread_create_on_cpu(), this means they must park their threads before stopping them, which is a bit silly. While we could change kthread_unpark() to only do the rebind if it is required, using kthread_create_on_cpu() for anything else than smpboot threads is risky: they won't get parked/unparked during a hotplug cycle, so their affinity will just be reset as soon as their respective CPU goes out. The PSCI checker only lives during initcalls and explicitly points out that it cannot exist concurrently with hotplug operations, so let's just make it use kthread_create_on_node() + kthread_bind() (similar to what e.g. RCU torture does). Signed-off-by: Valentin Schneider --- drivers/firmware/psci/psci_checker.c | 32 +++++++++++----------------- 1 file changed, 12 insertions(+), 20 deletions(-) diff --git a/drivers/firmware/psci/psci_checker.c b/drivers/firmware/psci/psci_checker.c index a5279a430274..fa7bb1e8a461 100644 --- a/drivers/firmware/psci/psci_checker.c +++ b/drivers/firmware/psci/psci_checker.c @@ -347,19 +347,12 @@ static int suspend_test_thread(void *arg) if (atomic_dec_return_relaxed(&nb_active_threads) == 0) complete(&suspend_threads_done); - for (;;) { - /* Needs to be set first to avoid missing a wakeup. */ - set_current_state(TASK_INTERRUPTIBLE); - if (kthread_should_park()) - break; - schedule(); - } + while (!kthread_should_stop()) + schedule_timeout_interruptible(MAX_SCHEDULE_TIMEOUT); pr_info("CPU %d suspend test results: success %d, shallow states %d, errors %d\n", cpu, nb_suspend, nb_shallow_sleep, nb_err); - kthread_parkme(); - return nb_err; } @@ -395,13 +388,15 @@ static int suspend_tests(void) continue; } - thread = kthread_create_on_cpu(suspend_test_thread, - (void *)(long)cpu, cpu, - "psci_suspend_test"); - if (IS_ERR(thread)) + thread = kthread_create_on_node(suspend_test_thread, + (void *)(long)cpu, cpu_to_node(cpu), + "psci_suspend_test/%d", cpu); + if (IS_ERR(thread)) { pr_err("Failed to create kthread on CPU %d\n", cpu); - else + } else { threads[nb_threads++] = thread; + kthread_bind(thread, cpu); + } } if (nb_threads < 1) { @@ -418,17 +413,14 @@ static int suspend_tests(void) */ for (i = 0; i < nb_threads; ++i) wake_up_process(threads[i]); - complete_all(&suspend_threads_started); + complete_all(&suspend_threads_started); wait_for_completion(&suspend_threads_done); - /* Stop and destroy all threads, get return status. */ - for (i = 0; i < nb_threads; ++i) { - err += kthread_park(threads[i]); + for (i = 0; i < nb_threads; ++i) err += kthread_stop(threads[i]); - } - out: +out: cpuidle_resume_and_unlock(); kfree(threads); return err; From patchwork Fri Apr 24 13:56:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Valentin Schneider X-Patchwork-Id: 11507937 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 07FEC1575 for ; Fri, 24 Apr 2020 13:58:54 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DA9F72084D for ; Fri, 24 Apr 2020 13:58:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="JMa0Z9/X" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DA9F72084D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=SFgXi/dClnfKXj6Rch/e2ZYJmIWEh0N8gukc7tavoTA=; b=JMa0Z9/XKp/ajd 5polpPGZA2ddMgrNFy5kH7uPBIyJwPS0I328wERPzTxMN+Iiay226km1MNoKvDrUlXIi2i9hKERCv xa0ve2256DY3hQkFpNRUb07hfleKDyodFb3aAYChhdqm+m7VIUCNOTIXkrAc4w7YAA7SQkktv32xg THH1K1J7IV1tedxO32505D/CS25hy1H/AUoWk+AOl0HKB8LsI/lDbFEGBpfEBM7Yjjl0lale1/3Nb +SfJXHk4HZ3WfdeVF7AMs+b0wasVzlmAQQOZdiAIHnt3qfNClDykQBW0M8OX+/DAymEhdiIU/fOvZ +rcLmPpFciZmm0m9SYPg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRyqu-0007GO-6Z; Fri, 24 Apr 2020 13:58:48 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRyqO-0006mz-FY for linux-arm-kernel@lists.infradead.org; Fri, 24 Apr 2020 13:58:19 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9607D1063; Fri, 24 Apr 2020 06:58:15 -0700 (PDT) Received: from e113632-lin.cambridge.arm.com (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 978053F68F; Fri, 24 Apr 2020 06:58:14 -0700 (PDT) From: Valentin Schneider To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/2] firmware/psci: Make PSCI checker use play_idle() Date: Fri, 24 Apr 2020 14:56:57 +0100 Message-Id: <20200424135657.32519-3-valentin.schneider@arm.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20200424135657.32519-1-valentin.schneider@arm.com> References: <20200424135657.32519-1-valentin.schneider@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200424_065816_604402_32535ACE X-CRM114-Status: GOOD ( 24.35 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Zijlstra , Lorenzo Pieralisi , Sudeep Holla Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org To test if we can reach all idle states, the checker implements a minimalist open-coded version of do_idle(). While it gets the job done, it's not the nicest way to go about it. What we can do instead is to nudge cpuidle to go for the idle state we want with cpuidle_use_deepest_state(), go idle via play_idle(), and check the cpuidle usage stats to see which idle state we entered. We don't directly get the state.enter() return value anymore, but if we never enter a given idle state throughout the entire test, then that should be a good indicator that something is off. Suggested-by: Peter Zijlstra Signed-off-by: Valentin Schneider --- drivers/firmware/psci/psci_checker.c | 131 +++++++-------------------- 1 file changed, 32 insertions(+), 99 deletions(-) diff --git a/drivers/firmware/psci/psci_checker.c b/drivers/firmware/psci/psci_checker.c index fa7bb1e8a461..722df252af28 100644 --- a/drivers/firmware/psci/psci_checker.c +++ b/drivers/firmware/psci/psci_checker.c @@ -226,56 +226,15 @@ static int hotplug_tests(void) return err; } -static void dummy_callback(struct timer_list *unused) {} - -static int suspend_cpu(struct cpuidle_device *dev, - struct cpuidle_driver *drv, int index) -{ - struct cpuidle_state *state = &drv->states[index]; - bool broadcast = state->flags & CPUIDLE_FLAG_TIMER_STOP; - int ret; - - arch_cpu_idle_enter(); - - if (broadcast) { - /* - * The local timer will be shut down, we need to enter tick - * broadcast. - */ - ret = tick_broadcast_enter(); - if (ret) { - /* - * In the absence of hardware broadcast mechanism, - * this CPU might be used to broadcast wakeups, which - * may be why entering tick broadcast has failed. - * There is little the kernel can do to work around - * that, so enter WFI instead (idle state 0). - */ - cpu_do_idle(); - ret = 0; - goto out_arch_exit; - } - } - - ret = state->enter(dev, drv, index); - - if (broadcast) - tick_broadcast_exit(); - -out_arch_exit: - arch_cpu_idle_exit(); - - return ret; -} - -static int suspend_test_thread(void *arg) +static int suspend_test_thread(void *__unused) { - int cpu = (long)arg; - int i, nb_suspend = 0, nb_shallow_sleep = 0, nb_err = 0; + DECLARE_BITMAP(states_reached, CPUIDLE_STATE_MAX); struct cpuidle_device *dev; struct cpuidle_driver *drv; - /* No need for an actual callback, we just want to wake up the CPU. */ - struct timer_list wakeup_timer; + int cpu = smp_processor_id(); + int i, nr_states; + int nr_shallows = 0; + bool pass; /* Wait for the main thread to give the start signal. */ wait_for_completion(&suspend_threads_started); @@ -286,11 +245,12 @@ static int suspend_test_thread(void *arg) dev = this_cpu_read(cpuidle_devices); drv = cpuidle_get_cpu_driver(dev); + nr_states = drv->state_count; + bitmap_zero(states_reached, CPUIDLE_STATE_MAX); pr_info("CPU %d entering suspend cycles, states 1 through %d\n", cpu, drv->state_count - 1); - timer_setup_on_stack(&wakeup_timer, dummy_callback, 0); for (i = 0; i < NUM_SUSPEND_CYCLE; ++i) { int index; /* @@ -298,62 +258,45 @@ static int suspend_test_thread(void *arg) * doesn't use PSCI). */ for (index = 1; index < drv->state_count; ++index) { - int ret; struct cpuidle_state *state = &drv->states[index]; + unsigned long long prev, next; + prev = READ_ONCE(dev->states_usage[index].usage); /* - * Set the timer to wake this CPU up in some time (which - * should be largely sufficient for entering suspend). - * If the local tick is disabled when entering suspend, - * suspend_cpu() takes care of switching to a broadcast - * tick, so the timer will still wake us up. + * This will attempt to go into the deepest idle state + * possible. By specifying the exit latency, we prevent + * higher idle states from being picked, so we should + * end up in the one idle state we want. This may cause + * issues if there are several idle states with + * identical exit latency, but who does that? */ - mod_timer(&wakeup_timer, jiffies + - usecs_to_jiffies(state->target_residency)); - - /* IRQs must be disabled during suspend operations. */ - local_irq_disable(); + play_idle_precise(state->target_residency_ns, + state->exit_latency_ns); - ret = suspend_cpu(dev, drv, index); + next = READ_ONCE(dev->states_usage[index].usage); - /* - * We have woken up. Re-enable IRQs to handle any - * pending interrupt, do not wait until the end of the - * loop. - */ - local_irq_enable(); - - if (ret == index) { - ++nb_suspend; - } else if (ret >= 0) { - /* We did not enter the expected state. */ - ++nb_shallow_sleep; - } else { - pr_err("Failed to suspend CPU %d: error %d " - "(requested state %d, cycle %d)\n", - cpu, ret, index, i); - ++nb_err; - } + if (prev != next) + bitmap_set(states_reached, index, 1); + else + nr_shallows++; } } - /* - * Disable the timer to make sure that the timer will not trigger - * later. - */ - del_timer(&wakeup_timer); - destroy_timer_on_stack(&wakeup_timer); + /* Assert we reached each state at least once */ + pass = bitmap_weight(states_reached, CPUIDLE_STATE_MAX) == nr_states - 1; if (atomic_dec_return_relaxed(&nb_active_threads) == 0) complete(&suspend_threads_done); + pr_info("CPU %d suspend results: reached %d states out of %d (%d/%d misses)\n", + cpu, bitmap_weight(states_reached, CPUIDLE_STATE_MAX), + nr_states - 1, nr_shallows, + (nr_states - 1) * NUM_SUSPEND_CYCLE); + while (!kthread_should_stop()) schedule_timeout_interruptible(MAX_SCHEDULE_TIMEOUT); - pr_info("CPU %d suspend test results: success %d, shallow states %d, errors %d\n", - cpu, nb_suspend, nb_shallow_sleep, nb_err); - - return nb_err; + return !pass; } static int suspend_tests(void) @@ -367,15 +310,6 @@ static int suspend_tests(void) if (!threads) return -ENOMEM; - /* - * Stop cpuidle to prevent the idle tasks from entering a deep sleep - * mode, as it might interfere with the suspend threads on other CPUs. - * This does not prevent the suspend threads from using cpuidle (only - * the idle tasks check this status). Take the idle lock so that - * the cpuidle driver and device look-up can be carried out safely. - */ - cpuidle_pause_and_lock(); - for_each_online_cpu(cpu) { struct task_struct *thread; /* Check that cpuidle is available on that CPU. */ @@ -389,7 +323,7 @@ static int suspend_tests(void) } thread = kthread_create_on_node(suspend_test_thread, - (void *)(long)cpu, cpu_to_node(cpu), + NULL, cpu_to_node(cpu), "psci_suspend_test/%d", cpu); if (IS_ERR(thread)) { pr_err("Failed to create kthread on CPU %d\n", cpu); @@ -421,7 +355,6 @@ static int suspend_tests(void) for (i = 0; i < nb_threads; ++i) err += kthread_stop(threads[i]); out: - cpuidle_resume_and_unlock(); kfree(threads); return err; }