From patchwork Tue Jul 20 14:18:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12388429 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 9876EC07E9B for ; Tue, 20 Jul 2021 14:26:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8531A610CC for ; Tue, 20 Jul 2021 14:26:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239710AbhGTNp7 (ORCPT ); Tue, 20 Jul 2021 09:45:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:57662 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231713AbhGTNjI (ORCPT ); Tue, 20 Jul 2021 09:39:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626790786; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=9rN1rhrGAmjoIQEBqysfuy+nlrq3d0bQU+TwRDEyQg8=; b=CT03EPUkcRdm2P927PpjLzAk0pDmDITlge8hqyqH1up9UT5cFxZrkizZa7iVutRjIUfNEc 2J7/9nix70TkdzZUZQ0YVpbLOhfoLyt5bXBF5wKiagx+rghS48W8Onq8ROKJoEX61IJFYf hiXYTEx6WLzWhH7jPiJFuFBfZBDIepw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-31-VPuCQdTBMcyJW2NPAdD-bA-1; Tue, 20 Jul 2021 10:19:43 -0400 X-MC-Unique: VPuCQdTBMcyJW2NPAdD-bA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 94E4480365C; Tue, 20 Jul 2021 14:19:40 +0000 (UTC) Received: from llong.com (ovpn-116-153.rdu2.redhat.com [10.10.116.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id C8C9269FAD; Tue, 20 Jul 2021 14:19:36 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long Subject: [PATCH v3 1/9] cgroup/cpuset: Miscellaneous code cleanup Date: Tue, 20 Jul 2021 10:18:26 -0400 Message-Id: <20210720141834.10624-2-longman@redhat.com> In-Reply-To: <20210720141834.10624-1-longman@redhat.com> References: <20210720141834.10624-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Use more descriptive variable names for update_prstate(), remove unnecessary code and fix some typos. There is no functional change. Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 40 +++++++++++++++++++--------------------- 1 file changed, 19 insertions(+), 21 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index adb5190c4429..f5fef5516d99 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1114,7 +1114,7 @@ enum subparts_cmd { * cpus_allowed can be granted or an error code will be returned. * * For partcmd_disable, the cpuset is being transofrmed from a partition - * root back to a non-partition root. any CPUs in cpus_allowed that are in + * root back to a non-partition root. Any CPUs in cpus_allowed that are in * parent's subparts_cpus will be taken away from that cpumask and put back * into parent's effective_cpus. 0 should always be returned. * @@ -1225,7 +1225,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, /* * partcmd_update w/o newmask: * - * addmask = cpus_allowed & parent->effectiveb_cpus + * addmask = cpus_allowed & parent->effective_cpus * * Note that parent's subparts_cpus may have been * pre-shrunk in case there is a change in the cpu list. @@ -1365,12 +1365,12 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) case PRS_DISABLED: /* * If parent is not a partition root or an - * invalid partition root, clear the state - * state and the CS_CPU_EXCLUSIVE flag. + * invalid partition root, clear its state + * and its CS_CPU_EXCLUSIVE flag. */ WARN_ON_ONCE(cp->partition_root_state != PRS_ERROR); - cp->partition_root_state = 0; + cp->partition_root_state = PRS_DISABLED; /* * clear_bit() is an atomic operation and @@ -1937,30 +1937,28 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, /* * update_prstate - update partititon_root_state - * cs: the cpuset to update - * val: 0 - disabled, 1 - enabled + * cs: the cpuset to update + * new_prs: new partition root state * * Call with cpuset_mutex held. */ -static int update_prstate(struct cpuset *cs, int val) +static int update_prstate(struct cpuset *cs, int new_prs) { int err; struct cpuset *parent = parent_cs(cs); - struct tmpmasks tmp; + struct tmpmasks tmpmask; - if ((val != 0) && (val != 1)) - return -EINVAL; - if (val == cs->partition_root_state) + if (new_prs == cs->partition_root_state) return 0; /* * Cannot force a partial or invalid partition root to a full * partition root. */ - if (val && cs->partition_root_state) + if (new_prs && (cs->partition_root_state < 0)) return -EINVAL; - if (alloc_cpumasks(NULL, &tmp)) + if (alloc_cpumasks(NULL, &tmpmask)) return -ENOMEM; err = -EINVAL; @@ -1978,7 +1976,7 @@ static int update_prstate(struct cpuset *cs, int val) goto out; err = update_parent_subparts_cpumask(cs, partcmd_enable, - NULL, &tmp); + NULL, &tmpmask); if (err) { update_flag(CS_CPU_EXCLUSIVE, cs, 0); goto out; @@ -1990,18 +1988,18 @@ static int update_prstate(struct cpuset *cs, int val) * CS_CPU_EXCLUSIVE bit. */ if (cs->partition_root_state == PRS_ERROR) { - cs->partition_root_state = 0; + cs->partition_root_state = PRS_DISABLED; update_flag(CS_CPU_EXCLUSIVE, cs, 0); err = 0; goto out; } err = update_parent_subparts_cpumask(cs, partcmd_disable, - NULL, &tmp); + NULL, &tmpmask); if (err) goto out; - cs->partition_root_state = 0; + cs->partition_root_state = PRS_DISABLED; /* Turning off CS_CPU_EXCLUSIVE will not return error */ update_flag(CS_CPU_EXCLUSIVE, cs, 0); @@ -2015,11 +2013,11 @@ static int update_prstate(struct cpuset *cs, int val) update_tasks_cpumask(parent); if (parent->child_ecpus_count) - update_sibling_cpumasks(parent, cs, &tmp); + update_sibling_cpumasks(parent, cs, &tmpmask); rebuild_sched_domains_locked(); out: - free_cpumasks(NULL, &tmp); + free_cpumasks(NULL, &tmpmask); return err; } @@ -3060,7 +3058,7 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) goto retry; } - parent = parent_cs(cs); + parent = parent_cs(cs); compute_effective_cpumask(&new_cpus, cs, parent); nodes_and(new_mems, cs->mems_allowed, parent->effective_mems); From patchwork Tue Jul 20 14:18:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12388431 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 ADD55C6377A for ; 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Tue, 20 Jul 2021 10:19:47 -0400 X-MC-Unique: WujaTHGHP0eImPyl6Z3_gQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CB651100C660; Tue, 20 Jul 2021 14:19:45 +0000 (UTC) Received: from llong.com (ovpn-116-153.rdu2.redhat.com [10.10.116.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id BAE5E369A; Tue, 20 Jul 2021 14:19:40 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long Subject: [PATCH v3 2/9] cgroup/cpuset: Fix a partition bug with hotplug Date: Tue, 20 Jul 2021 10:18:27 -0400 Message-Id: <20210720141834.10624-3-longman@redhat.com> In-Reply-To: <20210720141834.10624-1-longman@redhat.com> References: <20210720141834.10624-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org In cpuset_hotplug_workfn(), the detection of whether the cpu list has been changed is done by comparing the effective cpus of the top cpuset with the cpu_active_mask. However, in the rare case that just all the CPUs in the subparts_cpus are offlined, the detection fails and the partition states are not updated correctly. Fix it by forcing the cpus_updated flag to true in this particular case. Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index f5fef5516d99..b00982e6f6d8 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3166,6 +3166,13 @@ static void cpuset_hotplug_workfn(struct work_struct *work) cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus); mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems); + /* + * In the rare case that hotplug removes just all the cpus in + * subparts_cpus, we assumed that cpus are updated. + */ + if (!cpus_updated && top_cpuset.nr_subparts_cpus) + cpus_updated = true; + /* synchronize cpus_allowed to cpu_active_mask */ if (cpus_updated) { spin_lock_irq(&callback_lock); From patchwork Tue Jul 20 14:18:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12388433 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 426D3C07E95 for ; Tue, 20 Jul 2021 14:26:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 208666101E for ; Tue, 20 Jul 2021 14:26:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239786AbhGTNqG (ORCPT ); Tue, 20 Jul 2021 09:46:06 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:36463 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239844AbhGTNjR (ORCPT ); Tue, 20 Jul 2021 09:39:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626790794; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=kydm/WGOt7L+xqgLRjO/qrii4XIoUJyUJ2jQIcmKKhI=; b=JbWA3MWHm/4hFmqaFQ7K60N2PdZOEI0srDrSL7p3yVOK3BC3BMhjGjT75Pl6dnFqMGJwgo G/QK5l2nqa2AJRztR6opTqMkpAugQpOSgEFkrWhb65YLzefV9PWjgGaoRmt03c7KkmXZRO Gt+7mqglzk0+wRHf5HxTk+JWmyvyTC8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-321-ASqZChOtMaub8Yl4V92dKA-1; Tue, 20 Jul 2021 10:19:53 -0400 X-MC-Unique: ASqZChOtMaub8Yl4V92dKA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5894B100C662; Tue, 20 Jul 2021 14:19:51 +0000 (UTC) Received: from llong.com (ovpn-116-153.rdu2.redhat.com [10.10.116.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id F1369369A; Tue, 20 Jul 2021 14:19:45 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long Subject: [PATCH v3 3/9] cgroup/cpuset: Fix violation of cpuset locking rule Date: Tue, 20 Jul 2021 10:18:28 -0400 Message-Id: <20210720141834.10624-4-longman@redhat.com> In-Reply-To: <20210720141834.10624-1-longman@redhat.com> References: <20210720141834.10624-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org The cpuset fields that manage partition root state do not strictly follow the cpuset locking rule that update to cpuset has to be done with both the callback_lock and cpuset_mutex held. This is now fixed by making sure that the locking rule is upheld. Fixes: 3881b86128d0 ("cpuset: Add an error state to cpuset.sched.partition") Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition) Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 58 +++++++++++++++++++++++++----------------- 1 file changed, 35 insertions(+), 23 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index b00982e6f6d8..04a6951abe2a 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1148,6 +1148,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, struct cpuset *parent = parent_cs(cpuset); int adding; /* Moving cpus from effective_cpus to subparts_cpus */ int deleting; /* Moving cpus from subparts_cpus to effective_cpus */ + int new_prs; bool part_error = false; /* Partition error? */ percpu_rwsem_assert_held(&cpuset_rwsem); @@ -1183,6 +1184,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, * A cpumask update cannot make parent's effective_cpus become empty. */ adding = deleting = false; + new_prs = cpuset->partition_root_state; if (cmd == partcmd_enable) { cpumask_copy(tmp->addmask, cpuset->cpus_allowed); adding = true; @@ -1247,11 +1249,11 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, switch (cpuset->partition_root_state) { case PRS_ENABLED: if (part_error) - cpuset->partition_root_state = PRS_ERROR; + new_prs = PRS_ERROR; break; case PRS_ERROR: if (!part_error) - cpuset->partition_root_state = PRS_ENABLED; + new_prs = PRS_ENABLED; break; } /* @@ -1260,10 +1262,10 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, part_error = (prev_prs == PRS_ERROR); } - if (!part_error && (cpuset->partition_root_state == PRS_ERROR)) + if (!part_error && (new_prs == PRS_ERROR)) return 0; /* Nothing need to be done */ - if (cpuset->partition_root_state == PRS_ERROR) { + if (new_prs == PRS_ERROR) { /* * Remove all its cpus from parent's subparts_cpus. */ @@ -1272,7 +1274,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, parent->subparts_cpus); } - if (!adding && !deleting) + if (!adding && !deleting && (new_prs == cpuset->partition_root_state)) return 0; /* @@ -1299,6 +1301,9 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, } parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus); + + if (cpuset->partition_root_state != new_prs) + cpuset->partition_root_state = new_prs; spin_unlock_irq(&callback_lock); return cmd == partcmd_update; @@ -1321,6 +1326,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) struct cpuset *cp; struct cgroup_subsys_state *pos_css; bool need_rebuild_sched_domains = false; + int new_prs; rcu_read_lock(); cpuset_for_each_descendant_pre(cp, pos_css, cs) { @@ -1360,7 +1366,8 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) * update_tasks_cpumask() again for tasks in the parent * cpuset if the parent's subparts_cpus changes. */ - if ((cp != cs) && cp->partition_root_state) { + new_prs = cp->partition_root_state; + if ((cp != cs) && new_prs) { switch (parent->partition_root_state) { case PRS_DISABLED: /* @@ -1370,7 +1377,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) */ WARN_ON_ONCE(cp->partition_root_state != PRS_ERROR); - cp->partition_root_state = PRS_DISABLED; + new_prs = PRS_DISABLED; /* * clear_bit() is an atomic operation and @@ -1391,11 +1398,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) /* * When parent is invalid, it has to be too. */ - cp->partition_root_state = PRS_ERROR; - if (cp->nr_subparts_cpus) { - cp->nr_subparts_cpus = 0; - cpumask_clear(cp->subparts_cpus); - } + new_prs = PRS_ERROR; break; } } @@ -1407,8 +1410,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) spin_lock_irq(&callback_lock); cpumask_copy(cp->effective_cpus, tmp->new_cpus); - if (cp->nr_subparts_cpus && - (cp->partition_root_state != PRS_ENABLED)) { + if (cp->nr_subparts_cpus && (new_prs != PRS_ENABLED)) { cp->nr_subparts_cpus = 0; cpumask_clear(cp->subparts_cpus); } else if (cp->nr_subparts_cpus) { @@ -1435,6 +1437,10 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) = cpumask_weight(cp->subparts_cpus); } } + + if (new_prs != cp->partition_root_state) + cp->partition_root_state = new_prs; + spin_unlock_irq(&callback_lock); WARN_ON(!is_in_v2_mode() && @@ -1944,25 +1950,25 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, */ static int update_prstate(struct cpuset *cs, int new_prs) { - int err; + int err, old_prs = cs->partition_root_state; struct cpuset *parent = parent_cs(cs); struct tmpmasks tmpmask; - if (new_prs == cs->partition_root_state) + if (old_prs == new_prs) return 0; /* * Cannot force a partial or invalid partition root to a full * partition root. */ - if (new_prs && (cs->partition_root_state < 0)) + if (new_prs && (old_prs == PRS_ERROR)) return -EINVAL; if (alloc_cpumasks(NULL, &tmpmask)) return -ENOMEM; err = -EINVAL; - if (!cs->partition_root_state) { + if (!old_prs) { /* * Turning on partition root requires setting the * CS_CPU_EXCLUSIVE bit implicitly as well and cpus_allowed @@ -1981,14 +1987,12 @@ static int update_prstate(struct cpuset *cs, int new_prs) update_flag(CS_CPU_EXCLUSIVE, cs, 0); goto out; } - cs->partition_root_state = PRS_ENABLED; } else { /* * Turning off partition root will clear the * CS_CPU_EXCLUSIVE bit. */ - if (cs->partition_root_state == PRS_ERROR) { - cs->partition_root_state = PRS_DISABLED; + if (old_prs == PRS_ERROR) { update_flag(CS_CPU_EXCLUSIVE, cs, 0); err = 0; goto out; @@ -1999,8 +2003,6 @@ static int update_prstate(struct cpuset *cs, int new_prs) if (err) goto out; - cs->partition_root_state = PRS_DISABLED; - /* Turning off CS_CPU_EXCLUSIVE will not return error */ update_flag(CS_CPU_EXCLUSIVE, cs, 0); } @@ -2017,6 +2019,12 @@ static int update_prstate(struct cpuset *cs, int new_prs) rebuild_sched_domains_locked(); out: + if (!err) { + spin_lock_irq(&callback_lock); + cs->partition_root_state = new_prs; + spin_unlock_irq(&callback_lock); + } + free_cpumasks(NULL, &tmpmask); return err; } @@ -3080,8 +3088,10 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) if (is_partition_root(cs) && (cpumask_empty(&new_cpus) || (parent->partition_root_state == PRS_ERROR))) { if (cs->nr_subparts_cpus) { + spin_lock_irq(&callback_lock); cs->nr_subparts_cpus = 0; cpumask_clear(cs->subparts_cpus); + spin_unlock_irq(&callback_lock); compute_effective_cpumask(&new_cpus, cs, parent); } @@ -3095,7 +3105,9 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) cpumask_empty(&new_cpus)) { update_parent_subparts_cpumask(cs, partcmd_disable, NULL, tmp); + spin_lock_irq(&callback_lock); cs->partition_root_state = PRS_ERROR; + spin_unlock_irq(&callback_lock); } cpuset_force_rebuild(); } From patchwork Tue Jul 20 14:18:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12388439 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 64333C07E95 for ; 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Tue, 20 Jul 2021 10:19:59 -0400 X-MC-Unique: AsULK73wOU-E_MuqCx3YSg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D6BDA1005E6A; Tue, 20 Jul 2021 14:19:56 +0000 (UTC) Received: from llong.com (ovpn-116-153.rdu2.redhat.com [10.10.116.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7E44219C87; Tue, 20 Jul 2021 14:19:51 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long Subject: [PATCH v3 4/9] cgroup/cpuset: Enable event notification when partition become invalid Date: Tue, 20 Jul 2021 10:18:29 -0400 Message-Id: <20210720141834.10624-5-longman@redhat.com> In-Reply-To: <20210720141834.10624-1-longman@redhat.com> References: <20210720141834.10624-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org A valid cpuset partition can become invalid if all its CPUs are offlined or somehow removed. This can happen through external events without "cpuset.cpus.partition" being touched at all. Users that rely on the property of a partition being present do not currently have a simple way to get such an event notified other than constant periodic polling which is both inefficient and cumbersome. To make life easier for those users, event notification is now enabled for "cpuset.cpus.partition" when it goes into or out of an invalid partition state. Suggested-by: Tejun Heo Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 49 ++++++++++++++++++++++++++++++++---------- 1 file changed, 38 insertions(+), 11 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 04a6951abe2a..2e34fc5b76f0 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -160,6 +160,9 @@ struct cpuset { */ int use_parent_ecpus; int child_ecpus_count; + + /* Handle for cpuset.cpus.partition */ + struct cgroup_file partition_file; }; /* @@ -263,6 +266,19 @@ static inline int is_partition_root(const struct cpuset *cs) return cs->partition_root_state > 0; } +/* + * Send notification event of partition_root_state change when going into + * or out of PRS_ERROR which may be due to an external event like hotplug. + */ +static inline void notify_partition_change(struct cpuset *cs, + int old_prs, int new_prs) +{ + if ((old_prs == new_prs) || + ((old_prs != PRS_ERROR) && (new_prs != PRS_ERROR))) + return; + cgroup_file_notify(&cs->partition_file); +} + static struct cpuset top_cpuset = { .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)), @@ -1148,7 +1164,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, struct cpuset *parent = parent_cs(cpuset); int adding; /* Moving cpus from effective_cpus to subparts_cpus */ int deleting; /* Moving cpus from subparts_cpus to effective_cpus */ - int new_prs; + int old_prs, new_prs; bool part_error = false; /* Partition error? */ percpu_rwsem_assert_held(&cpuset_rwsem); @@ -1184,7 +1200,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, * A cpumask update cannot make parent's effective_cpus become empty. */ adding = deleting = false; - new_prs = cpuset->partition_root_state; + old_prs = new_prs = cpuset->partition_root_state; if (cmd == partcmd_enable) { cpumask_copy(tmp->addmask, cpuset->cpus_allowed); adding = true; @@ -1274,7 +1290,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, parent->subparts_cpus); } - if (!adding && !deleting && (new_prs == cpuset->partition_root_state)) + if (!adding && !deleting && (new_prs == old_prs)) return 0; /* @@ -1302,9 +1318,11 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus); - if (cpuset->partition_root_state != new_prs) + if (old_prs != new_prs) cpuset->partition_root_state = new_prs; + spin_unlock_irq(&callback_lock); + notify_partition_change(cpuset, old_prs, new_prs); return cmd == partcmd_update; } @@ -1326,7 +1344,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) struct cpuset *cp; struct cgroup_subsys_state *pos_css; bool need_rebuild_sched_domains = false; - int new_prs; + int old_prs, new_prs; rcu_read_lock(); cpuset_for_each_descendant_pre(cp, pos_css, cs) { @@ -1366,8 +1384,8 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) * update_tasks_cpumask() again for tasks in the parent * cpuset if the parent's subparts_cpus changes. */ - new_prs = cp->partition_root_state; - if ((cp != cs) && new_prs) { + old_prs = new_prs = cp->partition_root_state; + if ((cp != cs) && old_prs) { switch (parent->partition_root_state) { case PRS_DISABLED: /* @@ -1438,10 +1456,11 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) } } - if (new_prs != cp->partition_root_state) + if (new_prs != old_prs) cp->partition_root_state = new_prs; spin_unlock_irq(&callback_lock); + notify_partition_change(cp, old_prs, new_prs); WARN_ON(!is_in_v2_mode() && !cpumask_equal(cp->cpus_allowed, cp->effective_cpus)); @@ -2023,6 +2042,7 @@ static int update_prstate(struct cpuset *cs, int new_prs) spin_lock_irq(&callback_lock); cs->partition_root_state = new_prs; spin_unlock_irq(&callback_lock); + notify_partition_change(cs, old_prs, new_prs); } free_cpumasks(NULL, &tmpmask); @@ -2708,6 +2728,7 @@ static struct cftype dfl_files[] = { .write = sched_partition_write, .private = FILE_PARTITION_ROOT, .flags = CFTYPE_NOT_ON_ROOT, + .file_offset = offsetof(struct cpuset, partition_file), }, { @@ -3103,11 +3124,17 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) */ if ((parent->partition_root_state == PRS_ERROR) || cpumask_empty(&new_cpus)) { + int old_prs; + update_parent_subparts_cpumask(cs, partcmd_disable, NULL, tmp); - spin_lock_irq(&callback_lock); - cs->partition_root_state = PRS_ERROR; - spin_unlock_irq(&callback_lock); + old_prs = cs->partition_root_state; + if (old_prs != PRS_ERROR) { + spin_lock_irq(&callback_lock); + cs->partition_root_state = PRS_ERROR; + spin_unlock_irq(&callback_lock); + notify_partition_change(cs, old_prs, PRS_ERROR); + } } cpuset_force_rebuild(); } From patchwork Tue Jul 20 14:18:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12388435 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 7BEB0C636C8 for ; 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Tue, 20 Jul 2021 10:20:01 -0400 X-MC-Unique: ac5GV_PSOfCLmnCyQdtcsA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B7697800050; Tue, 20 Jul 2021 14:19:58 +0000 (UTC) Received: from llong.com (ovpn-116-153.rdu2.redhat.com [10.10.116.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id 080B560BD8; Tue, 20 Jul 2021 14:19:56 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long Subject: [PATCH v3 5/9] cgroup/cpuset: Clarify the use of invalid partition root Date: Tue, 20 Jul 2021 10:18:30 -0400 Message-Id: <20210720141834.10624-6-longman@redhat.com> In-Reply-To: <20210720141834.10624-1-longman@redhat.com> References: <20210720141834.10624-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org For cpuset partition, the special state of PRS_ERROR (invalid partition root) was originally designed to handle hotplug events. In this state, CPUs allocated to the partition root is released back to the parent but the cpuset exclusive flags remain unchanged. Since partition root sets the CPU_EXCLUSIVE flag, cpuset.cpus changes that break the cpu exclusivity rule will not be allowed. However, other changes to cpuset.cpus on a partition root may still cause it to become invalid. This is undesriable as we don't want accidental change to cpuset.cpus to invalidate a partition root. Additional checks are now added to make sure that regular cpuset control file manipulations are not allowed to make a partition root invalid. These additional checks are: 1) A partition root can't be changed to member if it has child partition roots. 2) Removing CPUs from cpuset.cpus that causes it to become invalid is not allowed. Comments are also added to clarify that a partition root becomes invalid only when an external event like hotplug that causes all the CPUs allocated to a partition root to become unavailable. Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 144 ++++++++++++++++++++++++----------------- 1 file changed, 86 insertions(+), 58 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 2e34fc5b76f0..c16060b703cc 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -177,7 +177,9 @@ struct cpuset { * subparts_cpus. In this case, the cpuset is not a real partition * root anymore. However, the CPU_EXCLUSIVE bit will still be set * and the cpuset can be restored back to a partition root if the - * parent cpuset can give more CPUs back to this child cpuset. + * parent cpuset can give more CPUs back to this child cpuset. A + * partition root becomes invalid when all its cpus become unavailable + * like being offlined. */ #define PRS_DISABLED 0 #define PRS_ENABLED 1 @@ -1211,6 +1213,15 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, /* * partcmd_update with newmask: * + * Return error if newmask isn't a subset of + * (cpus_allowed | parent->effective_cpus). + */ + cpumask_or(tmp->addmask, cpuset->cpus_allowed, + parent->effective_cpus); + if (!cpumask_subset(newmask, tmp->addmask)) + return -EINVAL; + + /* * delmask = cpus_allowed & ~newmask & parent->subparts_cpus * addmask = newmask & parent->effective_cpus * & ~parent->subparts_cpus @@ -1223,7 +1234,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, adding = cpumask_andnot(tmp->addmask, tmp->addmask, parent->subparts_cpus); /* - * Return error if the new effective_cpus could become empty. + * Return error if parent's effective_cpus could become empty. */ if (adding && cpumask_equal(parent->effective_cpus, tmp->addmask)) { @@ -1239,20 +1250,35 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, return -EINVAL; cpumask_copy(tmp->addmask, parent->effective_cpus); } + + /* + * Return error if effective_cpus becomes empty or any CPU + * distributed to child partitions is deleted. + */ + if (deleting && + (cpumask_intersects(tmp->delmask, cpuset->subparts_cpus) || + cpumask_equal(tmp->delmask, cpuset->effective_cpus))) + return -EBUSY; } else { /* * partcmd_update w/o newmask: * * addmask = cpus_allowed & parent->effective_cpus * + * This gets invoked either due to a hotplug event or + * from update_cpumasks_hier() where we can't return an + * error. This can cause a partition root to become invalid + * in the case of a hotplug. + * * Note that parent's subparts_cpus may have been * pre-shrunk in case there is a change in the cpu list. * So no deletion is needed. */ adding = cpumask_and(tmp->addmask, cpuset->cpus_allowed, parent->effective_cpus); - part_error = cpumask_equal(tmp->addmask, - parent->effective_cpus); + part_error = (is_partition_root(cpuset) && + !parent->nr_subparts_cpus) || + cpumask_equal(tmp->addmask, parent->effective_cpus); } if (cmd == partcmd_update) { @@ -1427,33 +1453,27 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) spin_lock_irq(&callback_lock); - cpumask_copy(cp->effective_cpus, tmp->new_cpus); if (cp->nr_subparts_cpus && (new_prs != PRS_ENABLED)) { + /* + * Put all active subparts_cpus back to effective_cpus. + */ + cpumask_or(tmp->new_cpus, tmp->new_cpus, + cp->subparts_cpus); + cpumask_and(tmp->new_cpus, tmp->new_cpus, + cpu_active_mask); cp->nr_subparts_cpus = 0; cpumask_clear(cp->subparts_cpus); - } else if (cp->nr_subparts_cpus) { + } + + cpumask_copy(cp->effective_cpus, tmp->new_cpus); + if (cp->nr_subparts_cpus) { /* * Make sure that effective_cpus & subparts_cpus - * are mutually exclusive. - * - * In the unlikely event that effective_cpus - * becomes empty. we clear cp->nr_subparts_cpus and - * let its child partition roots to compete for - * CPUs again. + * of a partition root are mutually exclusive. */ cpumask_andnot(cp->effective_cpus, cp->effective_cpus, cp->subparts_cpus); - if (cpumask_empty(cp->effective_cpus)) { - cpumask_copy(cp->effective_cpus, tmp->new_cpus); - cpumask_clear(cp->subparts_cpus); - cp->nr_subparts_cpus = 0; - } else if (!cpumask_subset(cp->subparts_cpus, - tmp->new_cpus)) { - cpumask_andnot(cp->subparts_cpus, - cp->subparts_cpus, tmp->new_cpus); - cp->nr_subparts_cpus - = cpumask_weight(cp->subparts_cpus); - } + WARN_ON_ONCE(cpumask_empty(cp->effective_cpus)); } if (new_prs != old_prs) @@ -1462,7 +1482,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) spin_unlock_irq(&callback_lock); notify_partition_change(cp, old_prs, new_prs); - WARN_ON(!is_in_v2_mode() && + WARN_ON_ONCE(!is_in_v2_mode() && !cpumask_equal(cp->cpus_allowed, cp->effective_cpus)); update_tasks_cpumask(cp); @@ -1585,8 +1605,8 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, * Make sure that subparts_cpus is a subset of cpus_allowed. */ if (cs->nr_subparts_cpus) { - cpumask_andnot(cs->subparts_cpus, cs->subparts_cpus, - cs->cpus_allowed); + cpumask_and(cs->subparts_cpus, cs->subparts_cpus, + cs->cpus_allowed); cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus); } spin_unlock_irq(&callback_lock); @@ -2008,20 +2028,26 @@ static int update_prstate(struct cpuset *cs, int new_prs) } } else { /* - * Turning off partition root will clear the - * CS_CPU_EXCLUSIVE bit. + * Switch back to member is always allowed if PRS_ERROR. */ if (old_prs == PRS_ERROR) { - update_flag(CS_CPU_EXCLUSIVE, cs, 0); err = 0; - goto out; + goto reset_flag; } + /* + * A partition root cannot be reverted to member if some + * CPUs have been distributed to child partition roots. + */ + if (!cpumask_empty(cs->subparts_cpus)) + return -EBUSY; + err = update_parent_subparts_cpumask(cs, partcmd_disable, NULL, &tmpmask); if (err) goto out; +reset_flag: /* Turning off CS_CPU_EXCLUSIVE will not return error */ update_flag(CS_CPU_EXCLUSIVE, cs, 0); } @@ -3103,11 +3129,28 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) /* * In the unlikely event that a partition root has empty - * effective_cpus or its parent becomes erroneous, we have to - * transition it to the erroneous state. + * effective_cpus, we will have to force any child partitions, + * if present, to become invalid by setting nr_subparts_cpus to 0 + * without causing itself to become invalid. + */ + if (is_partition_root(cs) && cs->nr_subparts_cpus && + cpumask_empty(&new_cpus)) { + cs->nr_subparts_cpus = 0; + cpumask_clear(cs->subparts_cpus); + compute_effective_cpumask(&new_cpus, cs, parent); + } + + /* + * If empty effective_cpus or zero nr_subparts_cpus or its parent + * becomes erroneous, we have to transition it to the erroneous state. */ if (is_partition_root(cs) && (cpumask_empty(&new_cpus) || - (parent->partition_root_state == PRS_ERROR))) { + (parent->partition_root_state == PRS_ERROR) || + !parent->nr_subparts_cpus)) { + int old_prs; + + update_parent_subparts_cpumask(cs, partcmd_disable, + NULL, tmp); if (cs->nr_subparts_cpus) { spin_lock_irq(&callback_lock); cs->nr_subparts_cpus = 0; @@ -3116,38 +3159,23 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) compute_effective_cpumask(&new_cpus, cs, parent); } - /* - * If the effective_cpus is empty because the child - * partitions take away all the CPUs, we can keep - * the current partition and let the child partitions - * fight for available CPUs. - */ - if ((parent->partition_root_state == PRS_ERROR) || - cpumask_empty(&new_cpus)) { - int old_prs; - - update_parent_subparts_cpumask(cs, partcmd_disable, - NULL, tmp); - old_prs = cs->partition_root_state; - if (old_prs != PRS_ERROR) { - spin_lock_irq(&callback_lock); - cs->partition_root_state = PRS_ERROR; - spin_unlock_irq(&callback_lock); - notify_partition_change(cs, old_prs, PRS_ERROR); - } + old_prs = cs->partition_root_state; + if (old_prs != PRS_ERROR) { + spin_lock_irq(&callback_lock); + cs->partition_root_state = PRS_ERROR; + spin_unlock_irq(&callback_lock); + notify_partition_change(cs, old_prs, PRS_ERROR); } cpuset_force_rebuild(); } /* * On the other hand, an erroneous partition root may be transitioned - * back to a regular one or a partition root with no CPU allocated - * from the parent may change to erroneous. + * back to a regular one. */ - if (is_partition_root(parent) && - ((cs->partition_root_state == PRS_ERROR) || - !cpumask_intersects(&new_cpus, parent->subparts_cpus)) && - update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp)) + else if (is_partition_root(parent) && + (cs->partition_root_state == PRS_ERROR) && + update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp)) cpuset_force_rebuild(); update_tasks: From patchwork Tue Jul 20 14:18:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12388437 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 A402EC636C8 for ; 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Tue, 20 Jul 2021 10:20:07 -0400 X-MC-Unique: QcJfI7_0PIqLhHorFFw-mg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 47A3A107B031; Tue, 20 Jul 2021 14:20:04 +0000 (UTC) Received: from llong.com (ovpn-116-153.rdu2.redhat.com [10.10.116.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id E03C069CB4; Tue, 20 Jul 2021 14:19:58 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long Subject: [PATCH v3 6/9] cgroup/cpuset: Add a new isolated cpus.partition type Date: Tue, 20 Jul 2021 10:18:31 -0400 Message-Id: <20210720141834.10624-7-longman@redhat.com> In-Reply-To: <20210720141834.10624-1-longman@redhat.com> References: <20210720141834.10624-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=TBD commit 994fb794cb252edd124a46ca0994e37a4726a100 Author: Waiman Long Date: Sat, 19 Jun 2021 13:28:19 -0400 cgroup/cpuset: Add a new isolated cpus.partition type Cpuset v1 uses the sched_load_balance control file to determine if load balancing should be enabled. Cpuset v2 gets rid of sched_load_balance as its use may require disabling load balancing at cgroup root. For workloads that require very low latency like DPDK, the latency jitters caused by periodic load balancing may exceed the desired latency limit. When cpuset v2 is in use, the only way to avoid this latency cost is to use the "isolcpus=" kernel boot option to isolate a set of CPUs. After the kernel boot, however, there is no way to add or remove CPUs from this isolated set. For workloads that are more dynamic in nature, that means users have to provision enough CPUs for the worst case situation resulting in excess idle CPUs. To address this issue for cpuset v2, a new cpuset.cpus.partition type "isolated" is added which allows the creation of a cpuset partition without load balancing. This will allow system administrators to dynamically adjust the size of isolated partition to the current need of the workload without rebooting the system. Signed-off-by: Waiman Long Signed-off-by: Waiman Long Reviewed-by: Michal Koutný --- kernel/cgroup/cpuset.c | 48 +++++++++++++++++++++++++++++++++++++----- 1 file changed, 43 insertions(+), 5 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index c16060b703cc..60562346ecc1 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -172,6 +172,8 @@ struct cpuset { * * 1 - partition root * + * 2 - partition root without load balancing (isolated) + * * -1 - invalid partition root * None of the cpus in cpus_allowed can be put into the parent's * subparts_cpus. In this case, the cpuset is not a real partition @@ -183,6 +185,7 @@ struct cpuset { */ #define PRS_DISABLED 0 #define PRS_ENABLED 1 +#define PRS_ISOLATED 2 #define PRS_ERROR -1 /* @@ -1285,17 +1288,22 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, int prev_prs = cpuset->partition_root_state; /* - * Check for possible transition between PRS_ENABLED - * and PRS_ERROR. + * Check for possible transition between PRS_ERROR and + * PRS_ENABLED/PRS_ISOLATED. */ switch (cpuset->partition_root_state) { case PRS_ENABLED: + case PRS_ISOLATED: if (part_error) new_prs = PRS_ERROR; break; case PRS_ERROR: - if (!part_error) + if (part_error) + break; + if (is_sched_load_balance(cpuset)) new_prs = PRS_ENABLED; + else + new_prs = PRS_ISOLATED; break; } /* @@ -1434,6 +1442,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) break; case PRS_ENABLED: + case PRS_ISOLATED: if (update_parent_subparts_cpumask(cp, partcmd_update, NULL, tmp)) update_tasks_cpumask(parent); break; @@ -1453,7 +1462,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) spin_lock_irq(&callback_lock); - if (cp->nr_subparts_cpus && (new_prs != PRS_ENABLED)) { + if (cp->nr_subparts_cpus && (new_prs <= 0)) { /* * Put all active subparts_cpus back to effective_cpus. */ @@ -1992,6 +2001,7 @@ static int update_prstate(struct cpuset *cs, int new_prs) int err, old_prs = cs->partition_root_state; struct cpuset *parent = parent_cs(cs); struct tmpmasks tmpmask; + bool sched_domain_rebuilt = false; if (old_prs == new_prs) return 0; @@ -2026,6 +2036,22 @@ static int update_prstate(struct cpuset *cs, int new_prs) update_flag(CS_CPU_EXCLUSIVE, cs, 0); goto out; } + + if (new_prs == PRS_ISOLATED) { + /* + * Disable the load balance flag should not return an + * error unless the system is running out of memory. + */ + update_flag(CS_SCHED_LOAD_BALANCE, cs, 0); + sched_domain_rebuilt = true; + } + } else if (old_prs && new_prs) { + /* + * A change in load balance state only, no change in cpumasks. + */ + update_flag(CS_SCHED_LOAD_BALANCE, cs, (new_prs != PRS_ISOLATED)); + err = 0; + goto out; /* Sched domain is rebuilt in update_flag() */ } else { /* * Switch back to member is always allowed if PRS_ERROR. @@ -2050,6 +2076,12 @@ static int update_prstate(struct cpuset *cs, int new_prs) reset_flag: /* Turning off CS_CPU_EXCLUSIVE will not return error */ update_flag(CS_CPU_EXCLUSIVE, cs, 0); + + if (!is_sched_load_balance(cs)) { + /* Make sure load balance is on */ + update_flag(CS_SCHED_LOAD_BALANCE, cs, 1); + sched_domain_rebuilt = true; + } } /* @@ -2062,7 +2094,8 @@ static int update_prstate(struct cpuset *cs, int new_prs) if (parent->child_ecpus_count) update_sibling_cpumasks(parent, cs, &tmpmask); - rebuild_sched_domains_locked(); + if (!sched_domain_rebuilt) + rebuild_sched_domains_locked(); out: if (!err) { spin_lock_irq(&callback_lock); @@ -2564,6 +2597,9 @@ static int sched_partition_show(struct seq_file *seq, void *v) case PRS_ENABLED: seq_puts(seq, "root\n"); break; + case PRS_ISOLATED: + seq_puts(seq, "isolated\n"); + break; case PRS_DISABLED: seq_puts(seq, "member\n"); break; @@ -2590,6 +2626,8 @@ static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf, val = PRS_ENABLED; else if (!strcmp(buf, "member")) val = PRS_DISABLED; + else if (!strcmp(buf, "isolated")) + val = PRS_ISOLATED; else return -EINVAL; From patchwork Tue Jul 20 14:18:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12388441 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 694A3C07E9B for ; Tue, 20 Jul 2021 14:27:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54282611CE for ; 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Tue, 20 Jul 2021 10:20:21 -0400 X-MC-Unique: aWvaNLbPNRCwTtiixgJHuw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 31E1291275; Tue, 20 Jul 2021 14:20:19 +0000 (UTC) Received: from llong.com (ovpn-116-153.rdu2.redhat.com [10.10.116.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6CAB7369A; Tue, 20 Jul 2021 14:20:04 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long Subject: [PATCH v3 7/9] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs Date: Tue, 20 Jul 2021 10:18:32 -0400 Message-Id: <20210720141834.10624-8-longman@redhat.com> In-Reply-To: <20210720141834.10624-1-longman@redhat.com> References: <20210720141834.10624-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Currently, a parent partition root cannot distribute all its CPUs to child partition roots with no CPUs left. However in some use cases, a management application may want to create a parent partition root as a management unit with no task associated with it and has all its CPUs distributed to various child partition roots dynamically according to their needs. Leaving a cpu in the parent partition root in such a case is now a waste. To accommodate such use cases, a parent partition root can now have all its CPUs distributed to its child partition roots as long as: 1) it is not the top cpuset; and 2) there is no task directly associated with the parent. Once an empty parent partition root is formed, no new task can be moved into it. Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 90 +++++++++++++++++++++++++++++------------- 1 file changed, 63 insertions(+), 27 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 60562346ecc1..d4d0c091a0d3 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -284,6 +284,11 @@ static inline void notify_partition_change(struct cpuset *cs, cgroup_file_notify(&cs->partition_file); } +static inline int cpuset_has_tasks(const struct cpuset *cs) +{ + return cs->css.cgroup->nr_populated_csets; +} + static struct cpuset top_cpuset = { .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)), @@ -1191,22 +1196,32 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, if ((cmd != partcmd_update) && css_has_online_children(&cpuset->css)) return -EBUSY; - /* - * Enabling partition root is not allowed if not all the CPUs - * can be granted from parent's effective_cpus or at least one - * CPU will be left after that. - */ - if ((cmd == partcmd_enable) && - (!cpumask_subset(cpuset->cpus_allowed, parent->effective_cpus) || - cpumask_equal(cpuset->cpus_allowed, parent->effective_cpus))) - return -EINVAL; - /* * A cpumask update cannot make parent's effective_cpus become empty. */ adding = deleting = false; old_prs = new_prs = cpuset->partition_root_state; if (cmd == partcmd_enable) { + bool parent_is_top_cpuset = !parent_cs(parent); + bool no_cpu_in_parent = cpumask_equal(cpuset->cpus_allowed, + parent->effective_cpus); + /* + * Enabling partition root is not allowed if not all the CPUs + * can be granted from parent's effective_cpus. If the parent + * is the top cpuset, at least one CPU must be left after that. + */ + if (!cpumask_subset(cpuset->cpus_allowed, parent->effective_cpus) || + (parent_is_top_cpuset && no_cpu_in_parent)) + return -EINVAL; + + /* + * A non-top parent can be left with no CPU as long as there + * is no task directly associated with the parent. For such + * a parent, no new task can be moved into it. + */ + if (no_cpu_in_parent && cpuset_has_tasks(parent)) + return -EINVAL; + cpumask_copy(tmp->addmask, cpuset->cpus_allowed); adding = true; } else if (cmd == partcmd_disable) { @@ -1237,9 +1252,10 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, adding = cpumask_andnot(tmp->addmask, tmp->addmask, parent->subparts_cpus); /* - * Return error if parent's effective_cpus could become empty. + * Return error if parent's effective_cpus could become empty + * and there are tasks in the parent. */ - if (adding && + if (adding && cpuset_has_tasks(parent) && cpumask_equal(parent->effective_cpus, tmp->addmask)) { if (!deleting) return -EINVAL; @@ -1255,12 +1271,13 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, } /* - * Return error if effective_cpus becomes empty or any CPU - * distributed to child partitions is deleted. + * Return error if effective_cpus becomes empty with tasks + * or any CPU distributed to child partitions is deleted. */ if (deleting && (cpumask_intersects(tmp->delmask, cpuset->subparts_cpus) || - cpumask_equal(tmp->delmask, cpuset->effective_cpus))) + (cpumask_equal(tmp->delmask, cpuset->effective_cpus) && + cpuset_has_tasks(cpuset)))) return -EBUSY; } else { /* @@ -1281,7 +1298,8 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, parent->effective_cpus); part_error = (is_partition_root(cpuset) && !parent->nr_subparts_cpus) || - cpumask_equal(tmp->addmask, parent->effective_cpus); + (cpumask_equal(tmp->addmask, parent->effective_cpus) && + cpuset_has_tasks(parent)); } if (cmd == partcmd_update) { @@ -1388,9 +1406,15 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) /* * If it becomes empty, inherit the effective mask of the - * parent, which is guaranteed to have some CPUs. + * parent, which is guaranteed to have some CPUs unless + * it is a partition root that has explicitly distributed + * out all its CPUs. */ if (is_in_v2_mode() && cpumask_empty(tmp->new_cpus)) { + if (is_partition_root(cp) && + cpumask_equal(cp->cpus_allowed, cp->subparts_cpus)) + goto update_parent_subparts; + cpumask_copy(tmp->new_cpus, parent->effective_cpus); if (!cp->use_parent_ecpus) { cp->use_parent_ecpus = true; @@ -1412,6 +1436,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) continue; } +update_parent_subparts: /* * update_parent_subparts_cpumask() should have been called * for cs already in update_cpumask(). We should also call @@ -1482,7 +1507,8 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) */ cpumask_andnot(cp->effective_cpus, cp->effective_cpus, cp->subparts_cpus); - WARN_ON_ONCE(cpumask_empty(cp->effective_cpus)); + WARN_ON_ONCE(cpumask_empty(cp->effective_cpus) && + cpuset_has_tasks(cp)); } if (new_prs != old_prs) @@ -1816,7 +1842,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems) cp->effective_mems = *new_mems; spin_unlock_irq(&callback_lock); - WARN_ON(!is_in_v2_mode() && + WARN_ON_ONCE(!is_in_v2_mode() && !nodes_equal(cp->mems_allowed, cp->effective_mems)); update_tasks_nodemask(cp); @@ -2231,6 +2257,13 @@ static int cpuset_can_attach(struct cgroup_taskset *tset) (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))) goto out_unlock; + /* + * On default hierarchy, task cannot be moved to a cpuset with empty + * effective cpus. + */ + if (is_in_v2_mode() && cpumask_empty(cs->effective_cpus)) + goto out_unlock; + cgroup_taskset_for_each(task, css, tset) { ret = task_can_attach(task, cs->cpus_allowed); if (ret) @@ -3098,7 +3131,8 @@ hotplug_update_tasks(struct cpuset *cs, struct cpumask *new_cpus, nodemask_t *new_mems, bool cpus_updated, bool mems_updated) { - if (cpumask_empty(new_cpus)) + /* A partition root is allowed to have empty effective cpus */ + if (cpumask_empty(new_cpus) && !is_partition_root(cs)) cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus); if (nodes_empty(*new_mems)) *new_mems = parent_cs(cs)->effective_mems; @@ -3167,22 +3201,24 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) /* * In the unlikely event that a partition root has empty - * effective_cpus, we will have to force any child partitions, - * if present, to become invalid by setting nr_subparts_cpus to 0 - * without causing itself to become invalid. + * effective_cpus with tasks, we will have to force any child + * partitions, if present, to become invalid by setting + * nr_subparts_cpus to 0 without causing itself to become invalid. */ if (is_partition_root(cs) && cs->nr_subparts_cpus && - cpumask_empty(&new_cpus)) { + cpumask_empty(&new_cpus) && cpuset_has_tasks(cs)) { cs->nr_subparts_cpus = 0; cpumask_clear(cs->subparts_cpus); compute_effective_cpumask(&new_cpus, cs, parent); } /* - * If empty effective_cpus or zero nr_subparts_cpus or its parent - * becomes erroneous, we have to transition it to the erroneous state. + * If empty effective_cpus with tasks or zero nr_subparts_cpus or + * its parent becomes erroneous, we have to transition it to the + * erroneous state. */ - if (is_partition_root(cs) && (cpumask_empty(&new_cpus) || + if (is_partition_root(cs) && + ((cpumask_empty(&new_cpus) && cpuset_has_tasks(cs)) || (parent->partition_root_state == PRS_ERROR) || !parent->nr_subparts_cpus)) { int old_prs; From patchwork Tue Jul 20 14:18:33 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12388443 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 ADD9DC07E9B for ; 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Tue, 20 Jul 2021 10:20:23 -0400 X-MC-Unique: 0sglr9-zOWS3UqbaUwzhmg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1BFEB1084F4C; Tue, 20 Jul 2021 14:20:21 +0000 (UTC) Received: from llong.com (ovpn-116-153.rdu2.redhat.com [10.10.116.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id 586A8369A; Tue, 20 Jul 2021 14:20:19 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long Subject: [PATCH v3 8/9] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Date: Tue, 20 Jul 2021 10:18:33 -0400 Message-Id: <20210720141834.10624-9-longman@redhat.com> In-Reply-To: <20210720141834.10624-1-longman@redhat.com> References: <20210720141834.10624-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Update Documentation/admin-guide/cgroup-v2.rst on the newly introduced "isolated" cpuset partition type as well as the ability to create non-top cpuset partition with no cpu allocated to it. Signed-off-by: Waiman Long --- Documentation/admin-guide/cgroup-v2.rst | 94 +++++++++++++++---------- 1 file changed, 58 insertions(+), 36 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 5c7377b5bd3e..2e101a353ab1 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -2080,8 +2080,9 @@ Cpuset Interface Files It accepts only the following input values when written to. ======== ================================ - "root" a partition root - "member" a non-root member of a partition + "member" Non-root member of a partition + "root" Partition root + "isolated" Partition root without load balancing ======== ================================ When set to be a partition root, the current cgroup is the @@ -2090,9 +2091,14 @@ Cpuset Interface Files partition roots themselves and their descendants. The root cgroup is always a partition root. - There are constraints on where a partition root can be set. - It can only be set in a cgroup if all the following conditions - are true. + When set to "isolated", the CPUs in that partition root will + be in an isolated state without any load balancing from the + scheduler. Tasks in such a partition must be explicitly bound + to each individual CPU. + + There are constraints on where a partition root can be set + ("root" or "isolated"). It can only be set in a cgroup if all + the following conditions are true. 1) The "cpuset.cpus" is not empty and the list of CPUs are exclusive, i.e. they are not shared by any of its siblings. @@ -2103,51 +2109,67 @@ Cpuset Interface Files eliminating corner cases that have to be handled if such a condition is allowed. - Setting it to partition root will take the CPUs away from the - effective CPUs of the parent cgroup. Once it is set, this + Setting it to a partition root will take the CPUs away from + the effective CPUs of the parent cgroup. Once it is set, this file cannot be reverted back to "member" if there are any child cgroups with cpuset enabled. - A parent partition cannot distribute all its CPUs to its - child partitions. There must be at least one cpu left in the - parent partition. + A parent partition may distribute all its CPUs to its child + partitions as long as it is not the root cgroup and there is no + task directly associated with that parent partition. Otherwise, + there must be at least one cpu left in the parent partition. + A new task cannot be moved to a partition root with no effective + cpu. + + Once becoming a partition root, changes to "cpuset.cpus" + is generally allowed as long as the first condition above + (cpu exclusivity rule) is true. Other constraints for this + operation are as follows. - Once becoming a partition root, changes to "cpuset.cpus" is - generally allowed as long as the first condition above is true, - the change will not take away all the CPUs from the parent - partition and the new "cpuset.cpus" value is a superset of its - children's "cpuset.cpus" values. + 1) Any newly added CPUs must be a subset of the parent's + "cpuset.cpus.effective". + 2) Taking away all the CPUs from the parent's "cpuset.cpus.effective" + is only allowed if there is no task associated with the + parent partition. + 3) Deletion of CPUs that have been distributed to child partition + roots are not allowed. Sometimes, external factors like changes to ancestors' "cpuset.cpus" or cpu hotplug can cause the state of the partition - root to change. On read, the "cpuset.sched.partition" file - can show the following values. + root to change. On read, the "cpuset.cpus.partition" file can + show the following values. ============== ============================== "member" Non-root member of a partition "root" Partition root + "isolated" Partition root without load balancing "root invalid" Invalid partition root ============== ============================== - It is a partition root if the first 2 partition root conditions - above are true and at least one CPU from "cpuset.cpus" is - granted by the parent cgroup. - - A partition root can become invalid if none of CPUs requested - in "cpuset.cpus" can be granted by the parent cgroup or the - parent cgroup is no longer a partition root itself. In this - case, it is not a real partition even though the restriction - of the first partition root condition above will still apply. - The cpu affinity of all the tasks in the cgroup will then be - associated with CPUs in the nearest ancestor partition. - - An invalid partition root can be transitioned back to a - real partition root if at least one of the requested CPUs - can now be granted by its parent. In this case, the cpu - affinity of all the tasks in the formerly invalid partition - will be associated to the CPUs of the newly formed partition. - Changing the partition state of an invalid partition root to - "member" is always allowed even if child cpusets are present. + A partition root becomes invalid if all the CPUs requested in + "cpuset.cpus" become unavailable. This can happen if all the + CPUs have been offlined, or the state of an ancestor partition + root become invalid. In this case, it is not a real partition + even though the restriction of the cpu exclusivity rule will + still apply. The cpu affinity of all the tasks in the cgroup + will then be associated with CPUs in the nearest ancestor + partition. + + In the special case of a parent partition competing with a child + partition for the only CPU left, the parent partition wins and + the child partition becomes invalid. + + An invalid partition root can be transitioned back to a real + partition root if at least one of the requested CPUs become + available again. In this case, the cpu affinity of all the tasks + in the formerly invalid partition will be associated to the CPUs + of the newly formed partition. Changing the partition state of + an invalid partition root to "member" is always allowed even if + child cpusets are present. However changing a partition root back + to member will not be allowed if child partitions are present. + + Poll and inotify events are triggered when transition to or + from invalid partition root happens. Device controller From patchwork Tue Jul 20 14:18:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12388445 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=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 57BB8C07E95 for ; Tue, 20 Jul 2021 14:27:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3DEB66101E for ; Tue, 20 Jul 2021 14:27:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239902AbhGTNqT (ORCPT ); Tue, 20 Jul 2021 09:46:19 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:58981 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240068AbhGTNjt (ORCPT ); Tue, 20 Jul 2021 09:39:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626790826; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=OZuObOR2cYOQ/uwIG7h7BaaIBTH4eDm4/meYdxIUli8=; b=ICg+ZGer4yTuJgCidQC0dghADpqSCWxTy759mSYUmgetFkjJmrOV4T06bxjb2BXfJ2yXh+ zLj8D4s/cp5X9RpIlc4zZ99Q45HDJWA+DXY6lJxXkyFgj9cwY+Qen89VFHq7z9KomKLGoc c2ne9nNiX890XJgsX1+eA++iPPjhFfg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-288-nHdVozpMO1eX5hcoietVVg-1; Tue, 20 Jul 2021 10:20:24 -0400 X-MC-Unique: nHdVozpMO1eX5hcoietVVg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1B5B291274; Tue, 20 Jul 2021 14:20:23 +0000 (UTC) Received: from llong.com (ovpn-116-153.rdu2.redhat.com [10.10.116.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4470019CBA; Tue, 20 Jul 2021 14:20:21 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long Subject: [PATCH v3 9/9] kselftest/cgroup: Add cpuset v2 partition root state test Date: Tue, 20 Jul 2021 10:18:34 -0400 Message-Id: <20210720141834.10624-10-longman@redhat.com> In-Reply-To: <20210720141834.10624-1-longman@redhat.com> References: <20210720141834.10624-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Add a test script test_cpuset_prs.sh with a helper program wait_inotify for exercising the cpuset v2 partition root state code. Signed-off-by: Waiman Long --- tools/testing/selftests/cgroup/Makefile | 5 +- .../selftests/cgroup/test_cpuset_prs.sh | 626 ++++++++++++++++++ tools/testing/selftests/cgroup/wait_inotify.c | 67 ++ 3 files changed, 696 insertions(+), 2 deletions(-) create mode 100755 tools/testing/selftests/cgroup/test_cpuset_prs.sh create mode 100644 tools/testing/selftests/cgroup/wait_inotify.c diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile index 59e222460581..3f1fd3f93f41 100644 --- a/tools/testing/selftests/cgroup/Makefile +++ b/tools/testing/selftests/cgroup/Makefile @@ -1,10 +1,11 @@ # SPDX-License-Identifier: GPL-2.0 CFLAGS += -Wall -pthread -all: +all: ${HELPER_PROGS} TEST_FILES := with_stress.sh -TEST_PROGS := test_stress.sh +TEST_PROGS := test_stress.sh test_cpuset_prs.sh +TEST_GEN_FILES := wait_inotify TEST_GEN_PROGS = test_memcontrol TEST_GEN_PROGS += test_kmem TEST_GEN_PROGS += test_core diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh new file mode 100755 index 000000000000..5a99f7048910 --- /dev/null +++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh @@ -0,0 +1,626 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Test for cpuset v2 partition root state (PRS) +# +# The sched verbose flag is set, if available, so that the console log +# can be examined for the correct setting of scheduling domain. +# + +skip_test() { + echo "$1" + echo "Test SKIPPED" + exit 0 +} + +[[ $(id -u) -eq 0 ]] || skip_test "Test must be run as root!" + +# Set sched verbose flag, if available +[[ -d /sys/kernel/debug/sched ]] && echo Y > /sys/kernel/debug/sched/verbose + +# Get wait_inotify location +WAIT_INOTIFY=$(cd $(dirname $0); pwd)/wait_inotify + +# Find cgroup v2 mount point +CGROUP2=$(mount -t cgroup2 | head -1 | awk -e '{print $3}') +[[ -n "$CGROUP2" ]] || skip_test "Cgroup v2 mount point not found!" + +CPUS=$(lscpu | grep "^CPU(s)" | sed -e "s/.*:[[:space:]]*//") +[[ $CPUS -lt 8 ]] && skip_test "Test needs at least 8 cpus available!" + +# Set verbose flag +VERBOSE= +[[ "$1" = -v ]] && VERBOSE=1 + +cd $CGROUP2 +echo +cpuset > cgroup.subtree_control +[[ -d test ]] || mkdir test +cd test + +console_msg() +{ + MSG=$1 + echo "$MSG" + echo "" > /dev/console + echo "$MSG" > /dev/console + sleep 0.01 +} + +test_partition() +{ + EXPECTED_VAL=$1 + echo $EXPECTED_VAL > cpuset.cpus.partition + [[ $? -eq 0 ]] || exit 1 + ACTUAL_VAL=$(cat cpuset.cpus.partition) + [[ $ACTUAL_VAL != $EXPECTED_VAL ]] && { + echo "cpuset.cpus.partition: expect $EXPECTED_VAL, found $EXPECTED_VAL" + echo "Test FAILED" + exit 1 + } +} + +test_effective_cpus() +{ + EXPECTED_VAL=$1 + ACTUAL_VAL=$(cat cpuset.cpus.effective) + [[ "$ACTUAL_VAL" != "$EXPECTED_VAL" ]] && { + echo "cpuset.cpus.effective: expect '$EXPECTED_VAL', found '$EXPECTED_VAL'" + echo "Test FAILED" + exit 1 + } +} + +# Adding current process to cgroup.procs as a test +test_add_proc() +{ + OUTSTR="$1" + ERRMSG=$((echo $$ > cgroup.procs) |& cat) + echo $ERRMSG | grep -q "$OUTSTR" + [[ $? -ne 0 ]] && { + echo "cgroup.procs: expect '$OUTSTR', got '$ERRMSG'" + echo "Test FAILED" + exit 1 + } + echo $$ > $CGROUP2/cgroup.procs # Move out the task +} + +# +# Testing the new "isolated" partition root type +# +test_isolated() +{ + echo 2-3 > cpuset.cpus + TYPE=$(cat cpuset.cpus.partition) + [[ $TYPE = member ]] || echo member > cpuset.cpus.partition + + console_msg "Change from member to root" + test_partition root + + console_msg "Change from root to isolated" + test_partition isolated + + console_msg "Change from isolated to member" + test_partition member + + console_msg "Change from member to isolated" + test_partition isolated + + console_msg "Change from isolated to root" + test_partition root + + console_msg "Change from root to member" + test_partition member + + # + # Testing partition root with no cpu + # + console_msg "Distribute all cpus to child partition" + echo +cpuset > cgroup.subtree_control + test_partition root + + mkdir A1 + cd A1 + echo 2-3 > cpuset.cpus + test_partition root + test_effective_cpus 2-3 + cd .. + test_effective_cpus "" + + console_msg "Moving task to partition test" + test_add_proc "No space left" + cd A1 + test_add_proc "" + cd .. + + console_msg "Shrink and expand child partition" + cd A1 + echo 2 > cpuset.cpus + cd .. + test_effective_cpus 3 + cd A1 + echo 2-3 > cpuset.cpus + cd .. + test_effective_cpus "" + + # Cleaning up + console_msg "Cleaning up" + echo $$ > $CGROUP2/cgroup.procs + [[ -d A1 ]] && rmdir A1 +} + +# +# Cpuset controller state transition test matrix. +# +# Cgroup test hierarchy +# +# test -- A1 -- A2 -- A3 +# \- B1 +# +# P = set cpus.partition (0:member, 1:root, 2:isolated, -1:root invalid) +# C = add cpu-list +# S

= use prefix in subtree_control +# T = put a task into cgroup +# O- = Write to CPU online file of +# +SETUP_A123_PARTITIONS="C1-3:P1:S+ C2-3:P1:S+ C3:P1" +TEST_MATRIX=( + # test old-A1 old-A2 old-A3 old-B1 new-A1 new-A2 new-A3 new-B1 fail ECPUs Pstate + # ---- ------ ------ ------ ------ ------ ------ ------ ------ ---- ----- ------ + " S+ C0-1 . . C2-3 S+ C4-5 . . 0 A2:0-1" + " S+ C0-1 . . C2-3 P1 . . . 0 " + " S+ C0-1 . . C2-3 P1:S+ C0-1:P1 . . 0 " + " S+ C0-1 . . C2-3 P1:S+ C1:P1 . . 0 " + " S+ C0-1:S+ . . C2-3 . . . P1 0 " + " S+ C0-1:P1 . . C2-3 S+ C1 . . 0 " + " S+ C0-1:P1 . . C2-3 S+ C1:P1 . . 0 " + " S+ C0-1:P1 . . C2-3 S+ C1:P1 . P1 0 " + " S+ C0-1:P1 . . C2-3 C4-5 . . . 0 A1:4-5" + " S+ C0-1:P1 . . C2-3 S+:C4-5 . . . 0 A1:4-5" + " S+ C0-1 . . C2-3:P1 . . . C2 0 " + " S+ C0-1 . . C2-3:P1 . . . C4-5 0 B1:4-5" + " S+ C0-3:P1:S+ C2-3:P1 . . . . . . 0 A1:0-1,A2:2-3" + " S+ C0-3:P1:S+ C2-3:P1 . . C1-3 . . . 0 A1:1,A2:2-3" + " S+ C2-3:P1:S+ C3:P1 . . C3 . . . 0 A1:,A2:3 A1:P1,A2:P1" + " S+ C2-3:P1:S+ C3:P1 . . C3 P0 . . 0 A1:3,A2:3 A1:P1,A2:P0" + " S+ C2-3:P1:S+ C2:P1 . . C2-4 . . . 0 A1:3-4,A2:2" + " S+ C2-3:P1:S+ C3:P1 . . C3 . . C0-2 0 A1:,B1:0-2 A1:P1,A2:P1" + " S+ $SETUP_A123_PARTITIONS . C2-3 . . . 0 A1:,A2:2,A3:3 A1:P1,A2:P1,A3:P1" + + # CPU offlining cases: + " S+ C0-1 . . C2-3 S+ C4-5 . O2-0 0 A1:0-1,B1:3" + " S+ C0-3:P1:S+ C2-3:P1 . . O2-0 . . . 0 A1:0-1,A2:3" + " S+ C0-3:P1:S+ C2-3:P1 . . O2-0 O2-1 . . 0 A1:0-1,A2:2-3" + " S+ C0-3:P1:S+ C2-3:P1 . . O1-0 . . . 0 A1:0,A2:2-3" + " S+ C0-3:P1:S+ C2-3:P1 . . O1-0 O1-1 . . 0 A1:0-1,A2:2-3" + " S+ C2-3:P1:S+ C3:P1 . . O3-0 O3-1 . . 0 A1:2,A2:3 A1:P1,A2:P1" + " S+ C2-3:P1:S+ C3:P2 . . O3-0 O3-1 . . 0 A1:2,A2:3 A1:P1,A2:P2" + " S+ C2-3:P1:S+ C3:P1 . . O2-0 O2-1 . . 0 A1:2,A2:3 A1:P1,A2:P1" + " S+ C2-3:P1:S+ C3:P2 . . O2-0 O2-1 . . 0 A1:2,A2:3 A1:P1,A2:P2" + " S+ C2-3:P1:S+ C3:P1 . . O2-0 . . . 0 A1:,A2:3 A1:P1,A2:P1" + " S+ C2-3:P1:S+ C3:P1 . . O3-0 . . . 0 A1:2,A2: A1:P1,A2:P1" + " S+ C2-3:P1:S+ C3:P1 . . T:O2-0 . . . 0 A1:3,A2:3 A1:P1,A2:P-1" + " S+ $SETUP_A123_PARTITIONS . O1-0 . . . 0 A1:,A2:2,A3:3 A1:P1,A2:P1,A3:P1" + " S+ $SETUP_A123_PARTITIONS . O2-0 . . . 0 A1:1,A2:,A3:3 A1:P1,A2:P1,A3:P1" + " S+ $SETUP_A123_PARTITIONS . O3-0 . . . 0 A1:1,A2:2,A3: A1:P1,A2:P1,A3:P1" + " S+ $SETUP_A123_PARTITIONS . T:O1-0 . . . 0 A1:2-3,A2:2-3,A3:3 A1:P1,A2:P-1,A3:P-1" + " S+ $SETUP_A123_PARTITIONS . . T:O2-0 . . 0 A1:1,A2:3,A3:3 A1:P1,A2:P1,A3:P-1" + " S+ $SETUP_A123_PARTITIONS . . . T:O3-0 . 0 A1:1,A2:2,A3:2 A1:P1,A2:P1,A3:P-1" + " S+ $SETUP_A123_PARTITIONS . T:O1-0 O1-1 . . 0 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1" + " S+ $SETUP_A123_PARTITIONS . . T:O2-0 O2-1 . 0 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1" + " S+ $SETUP_A123_PARTITIONS . . . T:O3-0 O3-1 0 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1" + " S+ $SETUP_A123_PARTITIONS . T:O1-0 O2-0 O1-1 . 0 A1:1,A2:,A3:3 A1:P1,A2:P1,A3:P1" + " S+ $SETUP_A123_PARTITIONS . T:O1-0 O2-0 O2-1 . 0 A1:2-3,A2:2-3,A3:3 A1:P1,A2:P-1,A3:P-1" + + # test old-A1 old-A2 old-A3 old-B1 new-A1 new-A2 new-A3 new-B1 fail ECPUs Pstate + # ---- ------ ------ ------ ------ ------ ------ ------ ------ ---- ----- ------ + # Failure cases: + + # To become a partition root, cpuset.cpus must be a subset of + # parent's cpuset.cpus.effective. + " S+ C0-1 . . C2-3 S+ C4-5:P1 . . 1 " + + # A cpuset cannot become a partition root if it has child cpusets + # with non-empty cpuset.cpus. + " S+ C0-1:S+ C1 . C2-3 P1 . . . 1 " + + # Any change to cpuset.cpus of a partition root must be exclusive. + " S+ C0-1:P1 . . C2-3 C0-2 . . . 1 " + " S+ C0-1 . . C2-3:P1 . . . C1 1 " + " S+ C2-3:P1:S+ C2:P1 . C1 C1-3 . . . 1 " + + # Deletion of CPUs distributed to child partition root is not allowed. + " S+ C0-1:P1:S+ C1 . C2-3 C4-5 . . . 1 " + " S+ C0-3:P1:S+ C2-3:P1 . . C0-2 . . . 1 " + + # Adding CPUs to partition root that are not in parent's + # cpuset.cpus.effective is not allowed. + " S+ C2-3:P1:S+ C3:P1 . . . C2-4 . . 1 " + + # Taking away all CPUs from parent or itself is not allowed if there are tasks. + " S+ C2-3:P1:S+ C3:P1 . . T C2-3 . . 1 A1:2,A2:3" + " S+ C1-3:P1:S+ C2-3:P1:S+ + C3:P1 . T:C2-3 . . . 1 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1" + + # A partition root cannot change to member if it has child partition. + " S+ C2-3:P1:S+ C3:P1 . . P0 . . . 1 " + " S+ $SETUP_A123_PARTITIONS . C2-3 P0 . . 1 A1:,A2:2,A3:3 A1:P1,A2:P1,A3:P1" + + # A task cannot be added to a partition with no cpu + " S+ C2-3:P1:S+ C3:P1 . . O2-0:T . . . 1 A1:,A2:3 A1:P1,A2:P1" + " S+ C2-3:P1:S+ C3:P1 . . O3-0 T . . 1 A1:2,A2: A1:P1,A2:P1" +) + +# +# Write to the cpu online file +# $1 - - where = cpu number, value to be written +# +write_cpu_online() +{ + CPU=${1%-*} + VAL=${1#*-} + CPUFILE=//sys/devices/system/cpu/cpu${CPU}/online + if [[ $VAL -eq 0 ]] + then + OFFLINE_CPUS="$OFFLINE_CPUS $CPU" + else + [[ -n "$OFFLINE_CPUS" ]] && { + OFFLINE_CPUS=$(echo $CPU $CPU $OFFLINE_CPUS | fmt -1 |\ + sort | uniq -u) + } + fi + echo $VAL > $CPUFILE + sleep 0.01 +} + +# +# Set controller state +# $1 - cgroup directory +# $2 - state +# $3 - showerr +# +# The presence of ":" in state means transition from one to the next. +# +set_ctrl_state() +{ + TMPMSG=/tmp/.msg_$$ + CGRP=$1 + STATE=$2 + SHOWERR=${3}${VERBOSE} + CTRL=${CTRL:=$CONTROLLER} + HASERR=0 + REDIRECT="2> $TMPMSG" + [[ -z "$STATE" || "$STATE" = '.' ]] && return 0 + + rm -f $TMPMSG + for CMD in $(echo $STATE | sed -e "s/:/ /g") + do + TFILE=$CGRP/cgroup.procs + SFILE=$CGRP/cgroup.subtree_control + PFILE=$CGRP/cpuset.cpus.partition + CFILE=$CGRP/cpuset.cpus + S=$(expr substr $CMD 1 1) + if [[ $S = S ]] + then + PREFIX=${CMD#?} + COMM="echo ${PREFIX}${CTRL} > $SFILE" + eval $COMM $REDIRECT + elif [[ $S = C ]] + then + CPUS=${CMD#?} + COMM="echo $CPUS > $CFILE" + eval $COMM $REDIRECT + elif [[ $S = P ]] + then + VAL=${CMD#?} + case $VAL in + 0) VAL=member + ;; + 1) VAL=root + ;; + 2) VAL=isolated + ;; + *) + echo "Invalid partiton state - $VAL" + exit 1 + ;; + esac + COMM="echo $VAL > $PFILE" + eval $COMM $REDIRECT + elif [[ $S = O ]] + then + VAL=${CMD#?} + write_cpu_online $VAL + elif [[ $S = T ]] + then + COMM="echo 0 > $TFILE" + eval $COMM $REDIRECT + fi + RET=$? + [[ $RET -ne 0 ]] && { + [[ -n "$SHOWERR" ]] && { + echo "$COMM" + cat $TMPMSG + } + HASERR=1 + } + sleep 0.01 + rm -f $TMPMSG + done + return $HASERR +} + +set_ctrl_state_noerr() +{ + CGRP=$1 + STATE=$2 + [[ -d $CGRP ]] || mkdir $CGRP + set_ctrl_state $CGRP $STATE 1 + [[ $? -ne 0 ]] && { + echo "ERROR: Failed to set $2 to cgroup $1!" + exit 1 + } +} + +online_cpus() +{ + [[ -n "OFFLINE_CPUS" ]] && { + for C in $OFFLINE_CPUS + do + write_cpu_online ${C}-1 + done + } +} + +# +# Return 1 if the list of effective cpus isn't the same as the initial list. +# +reset_cgroup_states() +{ + echo 0 > $CGROUP2/cgroup.procs + online_cpus + rmdir A1/A2/A3 A1/A2 A1 B1 > /dev/null 2>&1 + set_ctrl_state . S- + sleep 0.005 # 5ms artificial delay to complete the deletion +} + +dump_states() +{ + for DIR in A1 A1/A2 A1/A2/A3 B1 + do + ECPUS=$DIR/cpuset.cpus.effective + PRS=$DIR/cpuset.cpus.partition + [[ -e $ECPUS ]] && echo "$ECPUS: $(cat $ECPUS)" + [[ -e $PRS ]] && echo "$PRS: $(cat $PRS)" + done +} + +# +# Check effective cpus +# $1 - check string, format: :[,:]* +# +check_effective_cpus() +{ + CHK_STR=$1 + for CHK in $(echo $CHK_STR | sed -e "s/,/ /g") + do + set -- $(echo $CHK | sed -e "s/:/ /g") + CGRP=$1 + CPUS=$2 + [[ $CGRP = A2 ]] && CGRP=A1/A2 + [[ $CGRP = A3 ]] && CGRP=A1/A2/A3 + FILE=$CGRP/cpuset.cpus.effective + [[ -e $FILE ]] || return 1 + [[ $CPUS = $(cat $FILE) ]] || return 1 + done +} + +# +# Check cgroup states +# $1 - check string, format: :[,:]* +# +check_cgroup_states() +{ + CHK_STR=$1 + for CHK in $(echo $CHK_STR | sed -e "s/,/ /g") + do + set -- $(echo $CHK | sed -e "s/:/ /g") + CGRP=$1 + STATE=$2 + FILE= + EVAL=$(expr substr $STATE 2 2) + [[ $CGRP = A2 ]] && CGRP=A1/A2 + [[ $CGRP = A3 ]] && CGRP=A1/A2/A3 + + case $STATE in + P*) FILE=$CGRP/cpuset.cpus.partition + ;; + *) echo "Unknown state: $STATE!" + exit 1 + ;; + esac + VAL=$(cat $FILE) + + case "$VAL" in + member) VAL=0 + ;; + root) VAL=1 + ;; + isolated) + VAL=2 + ;; + "root invalid") + VAL=-1 + ;; + esac + [[ $EVAL != $VAL ]] && return 1 + done + return 0 +} + +# +# Run cpuset state transition test +# $1 - test matrix name +# +# This test is somewhat fragile as delays (sleep x) are added in various +# places to make sure state changes are fully propagated before the next +# action. These delays may need to be adjusted if running in a slower machine. +# +run_state_test() +{ + TEST=$1 + CONTROLLER=cpuset + I=0 + CPULIST=0-6 + eval CNT="\${#$TEST[@]}" + + reset_cgroup_states + echo $CPULIST > cpuset.cpus + echo root > cpuset.cpus.partition + console_msg "Running state transition test ..." + + while [[ $I -lt $CNT ]] + do + echo "Running test $I ..." > /dev/console + eval set -- "\${$TEST[$I]}" + ROOT=$1 + OLD_A1=$2 + OLD_A2=$3 + OLD_A3=$4 + OLD_B1=$5 + NEW_A1=$6 + NEW_A2=$7 + NEW_A3=$8 + NEW_B1=$9 + RESULT=${10} + ECPUS=${11} + STATES=${12} + + set_ctrl_state_noerr . $ROOT + set_ctrl_state_noerr A1 $OLD_A1 + set_ctrl_state_noerr A1/A2 $OLD_A2 + set_ctrl_state_noerr A1/A2/A3 $OLD_A3 + set_ctrl_state_noerr B1 $OLD_B1 + RETVAL=0 + set_ctrl_state A1 $NEW_A1; ((RETVAL += $?)) + set_ctrl_state A1/A2 $NEW_A2; ((RETVAL += $?)) + set_ctrl_state A1/A2/A3 $NEW_A3; ((RETVAL += $?)) + set_ctrl_state B1 $NEW_B1; ((RETVAL += $?)) + + [[ $RETVAL -ne $RESULT ]] && { + echo "Test $TEST[$I] failed result check!" + eval echo \"\${$TEST[$I]}\" + online_cpus + exit 1 + } + + [[ -n "$ECPUS" && "$ECPUS" != . ]] && { + check_effective_cpus $ECPUS + [[ $? -ne 0 ]] && { + echo "Test $TEST[$I] failed effective CPU check!" + eval echo \"\${$TEST[$I]}\" + echo + dump_states + online_cpus + exit 1 + } + } + + [[ -n "$STATES" ]] && { + check_cgroup_states $STATES + [[ $? -ne 0 ]] && { + echo "FAILED: Test $TEST[$I] failed states check!" + eval echo \"\${$TEST[$I]}\" + echo + dump_states + online_cpus + exit 1 + } + } + + reset_cgroup_states + [[ -n "$VERBOSE" ]] && echo "Test $I done." + ((I++)) + done + echo "All $I tests of $TEST PASSED." + + # + # Check to see if the effective cpu list changes + # + sleep 0.05 + NEWLIST=$(cat cpuset.cpus.effective) + [[ $NEWLIST != $CPULIST ]] && { + echo "Effective cpus changed to $NEWLIST!" + } + echo member > cpuset.cpus.partition +} + +# +# Wait for inotify event for the given file and read it +# $1: cgroup file to wait for +# $2: file to store the read result +# +wait_inotify() +{ + CGROUP_FILE=$1 + OUTPUT_FILE=$2 + + $WAIT_INOTIFY $CGROUP_FILE + cat $CGROUP_FILE > $OUTPUT_FILE +} + +# +# Test if inotify events are properly generated when going into and out of +# invalid partition state. +# +test_inotify() +{ + ERR=0 + PRS=/tmp/.prs_$$ + [[ -f $WAIT_INOTIFY ]] || { + echo "wait_inotify not found, inotify test SKIPPED." + return + } + + sleep 0.01 + echo 1 > cpuset.cpus + echo 0 > cgroup.procs + echo root > cpuset.cpus.partition + sleep 0.01 + rm -f $PRS + wait_inotify $PWD/cpuset.cpus.partition $PRS & + sleep 0.01 + set_ctrl_state . "O1-0" + sleep 0.01 + check_cgroup_states ".:P-1" + if [[ $? -ne 0 ]] + then + echo "FAILED: Inotify test - partition not invalid" + ERR=1 + elif [[ ! -f $PRS ]] + then + echo "FAILED: Inotify test - event not generated" + ERR=1 + kill %1 + elif [[ $(cat $PRS) != "root invalid" ]] + then + echo "FAILED: Inotify test - incorrect state" + cat $PRS + ERR=1 + fi + online_cpus + echo member > cpuset.cpus.partition + echo 0 > ../cgroup.procs + if [[ $ERR -ne 0 ]] + then + exit 1 + else + echo "Inotify test PASSED" + fi +} + +run_state_test TEST_MATRIX +test_isolated +test_inotify +echo "All tests PASSED." +cd .. +rmdir test diff --git a/tools/testing/selftests/cgroup/wait_inotify.c b/tools/testing/selftests/cgroup/wait_inotify.c new file mode 100644 index 000000000000..a6f80d008b4b --- /dev/null +++ b/tools/testing/selftests/cgroup/wait_inotify.c @@ -0,0 +1,67 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Wait until an inotify event on the given cgroup file. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +const char usage[] = "Usage: %s \n"; +static char *file; + +static inline void fail_message(char *msg) +{ + fprintf(stderr, msg, file); + exit(1); +} + +int main(int argc, char *argv[]) +{ + char *cmd = argv[0]; + int fd; + struct pollfd fds = { .events = POLLIN, }; + + if (argc != 2) { + fprintf(stderr, usage, cmd); + return -1; + } + file = argv[1]; + fd = open(file, O_RDONLY); + if (fd < 0) + fail_message("Cgroup file %s not found!\n"); + close(fd); + + fd = inotify_init(); + if (fd < 0) + fail_message("inotify_init() fails on %s!\n"); + if (inotify_add_watch(fd, file, IN_MODIFY) < 0) + fail_message("inotify_init() fails on %s!\n"); + fds.fd = fd; + + /* + * poll waiting loop + */ + for (;;) { + int ret = poll(&fds, 1, 10000); + if (ret < 0) { + if (errno == EINTR) + continue; + perror("poll"); + exit(1); + } + if ((ret > 0) && (fds.revents & POLLIN)) + break; + } + close(fd); + return 0; +}