From patchwork Wed Aug 25 21:37:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12458565 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=-16.5 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=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4DD49C4320E for ; Wed, 25 Aug 2021 21:40:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 357DB61101 for ; Wed, 25 Aug 2021 21:40:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229599AbhHYVk6 (ORCPT ); Wed, 25 Aug 2021 17:40:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:39691 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232844AbhHYVk5 (ORCPT ); Wed, 25 Aug 2021 17:40:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1629927611; 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=OGHOa0kZMjqxkrpym13f6OXtfzhe5zs6nSz2VwJyipQ=; b=TgnwFBJ0OEr3QxC65c8H6ESlKqPxzFZFbPWEF/Q618r+OgHYe6mN3pj6nHzjLecs7BFKZL gWVm28Iwn6g/nWdJOCeVlgWg8RDdQjLwLf8QCWnWMyn34WFSP2M7qCrgXEZcAOti3am8ch 5aNSVAQvQ5UmUtuRjEGtAmrXG4Ij3Mk= 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-143-xcZ0XEbGOAuE5FeOikx-Lw-1; Wed, 25 Aug 2021 17:40:09 -0400 X-MC-Unique: xcZ0XEbGOAuE5FeOikx-Lw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 90DEC8015C7; Wed, 25 Aug 2021 21:40:07 +0000 (UTC) Received: from llong.com (unknown [10.22.18.37]) by smtp.corp.redhat.com (Postfix) with ESMTP id 412DB6A056; Wed, 25 Aug 2021 21:40:03 +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 v7 1/6] cgroup/cpuset: Properly transition to invalid partition Date: Wed, 25 Aug 2021 17:37:45 -0400 Message-Id: <20210825213750.6933-2-longman@redhat.com> In-Reply-To: <20210825213750.6933-1-longman@redhat.com> References: <20210825213750.6933-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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. Changing a cpuset into a partition root is strictly controlled. The following constraints must be satisfied in order to make the transition possible: - The "cpuset.cpus" is not empty and the list of CPUs are exclusive, i.e. they are not shared by any of its siblings. - The parent cgroup is a partition root. - The "cpuset.cpus" is a subset of the parent's "cpuset.cpus.effective". - There is no child cgroups with cpuset enabled. Changing a partition root back to a member is always allowed, though care must be taken to make sure that this change won't break child cpusets, if present. 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. So users must always check the partition root state of "cpuset.cpus.partition" after making changes to cpuset.cpus to make sure that the partition root is still valid. For a partition root tree with parent and child partition roots, there are two cases where the child partitions can become invalid. Firstly, changing partition state to "member" will force the child partitions to become invalid. Secondly, if some cpus are taken away from the parent partition root so that its cpuset.cpus.effective becomes empty, it will try to pull cpus away from the child partitions and force them to become invalid which may allow the parent partition to remain valid. This patch makes sure that partitions are properly changed to invalid when some of the valid partition constraints are violated. Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 167 ++++++++++++++++++++++------------------- 1 file changed, 90 insertions(+), 77 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index d497a65c4f04..ddea05e4d1f0 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1177,10 +1177,9 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, return -EINVAL; /* - * Enabling/disabling partition root is not allowed if there are - * online children. + * Enabling partition root is not allowed if there are online children. */ - if ((cmd != partcmd_update) && css_has_online_children(&cpuset->css)) + if ((cmd == partcmd_enable) && css_has_online_children(&cpuset->css)) return -EBUSY; /* @@ -1208,6 +1207,14 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, /* * partcmd_update with newmask: * + * Make partition invalid if newmask isn't a subset of + * (cpus_allowed | parent->effective_cpus). + */ + cpumask_or(tmp->addmask, cpuset->cpus_allowed, + parent->effective_cpus); + part_error = !cpumask_subset(newmask, tmp->addmask); + + /* * delmask = cpus_allowed & ~newmask & parent->subparts_cpus * addmask = newmask & parent->effective_cpus * & ~parent->subparts_cpus @@ -1220,20 +1227,21 @@ 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. + * Make partition invalid if parent's effective_cpus could + * become empty. */ if (adding && cpumask_equal(parent->effective_cpus, tmp->addmask)) { if (!deleting) - return -EINVAL; + part_error = true; /* * As some of the CPUs in subparts_cpus might have * been offlined, we need to compute the real delmask * to confirm that. */ - if (!cpumask_and(tmp->addmask, tmp->delmask, - cpu_active_mask)) - return -EINVAL; + else if (!cpumask_and(tmp->addmask, tmp->delmask, + cpu_active_mask)) + part_error = true; cpumask_copy(tmp->addmask, parent->effective_cpus); } } else { @@ -1242,19 +1250,23 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, * * 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) { - int prev_prs = cpuset->partition_root_state; - /* * Check for possible transition between PRS_ENABLED * and PRS_ERROR. @@ -1269,13 +1281,9 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, new_prs = PRS_ENABLED; break; } - /* - * Set part_error if previously in invalid state. - */ - part_error = (prev_prs == PRS_ERROR); } - if (!part_error && (new_prs == PRS_ERROR)) + if ((old_prs == PRS_ERROR) && (new_prs == PRS_ERROR)) return 0; /* Nothing need to be done */ if (new_prs == PRS_ERROR) { @@ -1407,6 +1415,11 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) case PRS_ENABLED: if (update_parent_subparts_cpumask(cp, partcmd_update, NULL, tmp)) update_tasks_cpumask(parent); + /* + * The cpuset partition_root_state may be + * changed to PRS_ERROR. Capture it. + */ + new_prs = cp->partition_root_state; break; case PRS_ERROR: @@ -1424,33 +1437,27 @@ 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) @@ -1582,8 +1589,8 @@ 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); @@ -2010,20 +2017,24 @@ 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 even if it + * causes child partitions to become invalid. */ - if (old_prs == PRS_ERROR) { - update_flag(CS_CPU_EXCLUSIVE, cs, 0); - err = 0; - goto out; + err = 0; + update_parent_subparts_cpumask(cs, partcmd_disable, NULL, + &tmpmask); + /* + * If there are child partitions, we have to make them invalid. + */ + if (unlikely(cs->nr_subparts_cpus)) { + spin_lock_irq(&callback_lock); + cs->nr_subparts_cpus = 0; + cpumask_clear(cs->subparts_cpus); + compute_effective_cpumask(cs->effective_cpus, cs, parent); + spin_unlock_irq(&callback_lock); + update_cpumasks_hier(cs, &tmpmask); } - err = update_parent_subparts_cpumask(cs, partcmd_disable, - NULL, &tmpmask); - if (err) - goto out; - /* Turning off CS_CPU_EXCLUSIVE will not return error */ update_flag(CS_CPU_EXCLUSIVE, cs, 0); } @@ -3109,11 +3120,28 @@ 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; @@ -3122,38 +3150,23 @@ 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 Wed Aug 25 21:37:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12458567 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=-16.5 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=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 818F4C432BE for ; Wed, 25 Aug 2021 21:40:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AD476112D for ; Wed, 25 Aug 2021 21:40:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233612AbhHYVlF (ORCPT ); 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Wed, 25 Aug 2021 21:40:14 +0000 (UTC) Received: from llong.com (unknown [10.22.18.37]) by smtp.corp.redhat.com (Postfix) with ESMTP id B78EA1B472; Wed, 25 Aug 2021 21:40:07 +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 v7 2/6] cgroup/cpuset: Show invalid partition reason string Date: Wed, 25 Aug 2021 17:37:46 -0400 Message-Id: <20210825213750.6933-3-longman@redhat.com> In-Reply-To: <20210825213750.6933-1-longman@redhat.com> References: <20210825213750.6933-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org There are a number of different reasons which can cause a partition to become invalid. A user seeing an invalid partition may not know exactly why. To help user to get a better understanding of the underlying reason, The cpuset.cpus.partition control file, when read, will now report the reason why a partition become invalid. When a partition does become invalid, reading the control file will show "root invalid ()" where is a string that describes why the partition is invalid. Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 46 +++++++++++++++++++++++++++++++++++++++--- 1 file changed, 43 insertions(+), 3 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index ddea05e4d1f0..eb2e81f9326b 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -78,6 +78,24 @@ struct fmeter { spinlock_t lock; /* guards read or write of above */ }; +/* + * Invalid partition error code + */ +enum prs_errcode { + PERR_NONE = 0, + PERR_INVCPUS, + PERR_NOCPUS, + PERR_PARENT, + PERR_HOTPLUG, +}; + +static const char * const perr_strings[] = { + [PERR_INVCPUS] = "Invalid change to cpuset.cpus", + [PERR_PARENT] = "Parent is no longer a partition root", + [PERR_NOCPUS] = "Parent unable to distribute cpu downstream", + [PERR_HOTPLUG] = "No cpu available due to hotplug", +}; + struct cpuset { struct cgroup_subsys_state css; @@ -163,6 +181,9 @@ struct cpuset { /* Handle for cpuset.cpus.partition */ struct cgroup_file partition_file; + + /* Invalid partition error code, not lock protected */ + enum prs_errcode prs_err; }; /* @@ -272,8 +293,13 @@ static inline int is_partition_root(const struct cpuset *cs) static inline void notify_partition_change(struct cpuset *cs, int old_prs, int new_prs) { - if (old_prs != new_prs) - cgroup_file_notify(&cs->partition_file); + if (old_prs == new_prs) + return; + cgroup_file_notify(&cs->partition_file); + + /* Reset prs_err if not invalid */ + if (new_prs != PRS_ERROR) + WRITE_ONCE(cs->prs_err, PERR_NONE); } static struct cpuset top_cpuset = { @@ -1243,6 +1269,8 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, cpu_active_mask)) part_error = true; cpumask_copy(tmp->addmask, parent->effective_cpus); + if ((READ_ONCE(cpuset->prs_err) == PERR_NONE) && part_error) + WRITE_ONCE(cpuset->prs_err, PERR_INVCPUS); } } else { /* @@ -1264,6 +1292,8 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, part_error = (is_partition_root(cpuset) && !parent->nr_subparts_cpus) || cpumask_equal(tmp->addmask, parent->effective_cpus); + if (is_partition_root(cpuset) && part_error) + WRITE_ONCE(cpuset->prs_err, PERR_NOCPUS); } if (cmd == partcmd_update) { @@ -1427,6 +1457,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) * When parent is invalid, it has to be too. */ new_prs = PRS_ERROR; + WRITE_ONCE(cp->prs_err, PERR_PARENT); break; } } @@ -2546,6 +2577,7 @@ static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) static int sched_partition_show(struct seq_file *seq, void *v) { struct cpuset *cs = css_cs(seq_css(seq)); + const char *err; switch (cs->partition_root_state) { case PRS_ENABLED: @@ -2555,7 +2587,11 @@ static int sched_partition_show(struct seq_file *seq, void *v) seq_puts(seq, "member\n"); break; case PRS_ERROR: - seq_puts(seq, "root invalid\n"); + err = perr_strings[READ_ONCE(cs->prs_err)]; + if (err) + seq_printf(seq, "root invalid (%s)\n", err); + else + seq_puts(seq, "root invalid\n"); break; } return 0; @@ -3155,6 +3191,10 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) spin_lock_irq(&callback_lock); cs->partition_root_state = PRS_ERROR; spin_unlock_irq(&callback_lock); + if (parent->partition_root_state == PRS_ERROR) + WRITE_ONCE(cs->prs_err, PERR_PARENT); + else + WRITE_ONCE(cs->prs_err, PERR_HOTPLUG); notify_partition_change(cs, old_prs, PRS_ERROR); } cpuset_force_rebuild(); From patchwork Wed Aug 25 21:37:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12458569 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=-16.5 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 A5F83C432BE for ; Wed, 25 Aug 2021 21:40:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8BB57610FC for ; 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Wed, 25 Aug 2021 17:40:32 -0400 X-MC-Unique: ZmDp-QaXM_Op1_21tBY3Rg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4D8651026201; Wed, 25 Aug 2021 21:40:30 +0000 (UTC) Received: from llong.com (unknown [10.22.18.37]) by smtp.corp.redhat.com (Postfix) with ESMTP id B83B01B472; Wed, 25 Aug 2021 21:40:14 +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 v7 3/6] cgroup/cpuset: Add a new isolated cpus.partition type Date: Wed, 25 Aug 2021 17:37:47 -0400 Message-Id: <20210825213750.6933-4-longman@redhat.com> In-Reply-To: <20210825213750.6933-1-longman@redhat.com> References: <20210825213750.6933-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org 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 --- 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 eb2e81f9326b..de770a3781c2 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -193,6 +193,8 @@ 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 @@ -202,6 +204,7 @@ struct cpuset { */ #define PRS_DISABLED 0 #define PRS_ENABLED 1 +#define PRS_ISOLATED 2 #define PRS_ERROR -1 /* @@ -1298,17 +1301,22 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, if (cmd == partcmd_update) { /* - * 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; } } @@ -1443,6 +1451,7 @@ 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); /* @@ -1468,7 +1477,7 @@ 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. */ @@ -2012,6 +2021,7 @@ 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; @@ -2046,6 +2056,22 @@ 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 even if it @@ -2068,6 +2094,12 @@ static int update_prstate(struct cpuset *cs, int new_prs) /* 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; + } } /* @@ -2080,7 +2112,8 @@ 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); @@ -2583,6 +2616,9 @@ 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; @@ -2613,6 +2649,8 @@ 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 Wed Aug 25 21:37:48 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12458571 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=-16.5 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 5A0EEC4320E for ; Wed, 25 Aug 2021 21:40:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44FB361152 for ; 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Wed, 25 Aug 2021 17:40:34 -0400 X-MC-Unique: SSMgYd8qPamWat4W-XV_lg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E8613801A92; Wed, 25 Aug 2021 21:40:32 +0000 (UTC) Received: from llong.com (unknown [10.22.18.37]) by smtp.corp.redhat.com (Postfix) with ESMTP id 756051B472; Wed, 25 Aug 2021 21:40:30 +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 v7 4/6] cgroup/cpuset: Allow non-top parent partition to distribute out all CPUs Date: Wed, 25 Aug 2021 17:37:48 -0400 Message-Id: <20210825213750.6933-5-longman@redhat.com> In-Reply-To: <20210825213750.6933-1-longman@redhat.com> References: <20210825213750.6933-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Currently, a parent partition cannot distribute all its CPUs to child partitions with no CPUs left. However in some use cases, a management application may want to create a parent partition as a management unit with no task associated with it and has all its CPUs distributed to various child partitions dynamically according to their needs. Leaving a cpu in the parent partition in such a case is now a waste. To accommodate such use cases, a parent partition can now have all its CPUs distributed to its child partitions with 0 effective cpu left as long as it is not the top cpuset and it has no task at the time the child partition is being created. A terminal partition with no child partition underlying it, however, cannot have 0 effective cpu which will make the partition invalid. Once an empty parent partition is formed, no new task can be moved into it. Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 96 ++++++++++++++++++++++++++++++------------ 1 file changed, 69 insertions(+), 27 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index de770a3781c2..3658270d694c 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -305,6 +305,21 @@ static inline void notify_partition_change(struct cpuset *cs, WRITE_ONCE(cs->prs_err, PERR_NONE); } +static inline int cpuset_has_tasks(const struct cpuset *cs) +{ + return cs->css.cgroup->nr_populated_csets; +} + +/* + * A empty partition (one with no effective cpu) is valid if it has no + * associated task and all its cpus have been distributed out to child + * partitions. + */ +static inline bool valid_empty_partition(const struct cpuset *cs) +{ + return !cpuset_has_tasks(cs) && cs->nr_subparts_cpus; +} + static struct cpuset top_cpuset = { .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)), @@ -1211,22 +1226,32 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, if ((cmd == partcmd_enable) && 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) { @@ -1257,9 +1282,9 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, parent->subparts_cpus); /* * Make partition invalid if parent's effective_cpus could - * become empty. + * 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) part_error = true; @@ -1294,7 +1319,9 @@ 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 (is_partition_root(cpuset) && part_error) WRITE_ONCE(cpuset->prs_err, PERR_NOCPUS); } @@ -1397,9 +1424,15 @@ 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; @@ -1421,6 +1454,7 @@ 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 @@ -1497,12 +1531,9 @@ 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)); } - if (new_prs != old_prs) - cp->partition_root_state = new_prs; - + cp->partition_root_state = new_prs; spin_unlock_irq(&callback_lock); notify_partition_change(cp, old_prs, new_prs); @@ -2249,6 +2280,13 @@ 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) @@ -3125,7 +3163,8 @@ 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; @@ -3194,22 +3233,25 @@ 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)) { + if (is_partition_root(cs) && cpumask_empty(&new_cpus) && + !valid_empty_partition(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. + * Force the partition to become invalid if either one of + * the following conditions hold: + * 1) empty effective cpus but not valid empty partition. + * 2) parent is invalid or doesn't grant any cpus to child partitions. */ - if (is_partition_root(cs) && (cpumask_empty(&new_cpus) || + if (is_partition_root(cs) && + ((cpumask_empty(&new_cpus) && !valid_empty_partition(cs)) || (parent->partition_root_state == PRS_ERROR) || !parent->nr_subparts_cpus)) { int old_prs; From patchwork Wed Aug 25 21:37:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12458573 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=-16.5 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 389CAC43214 for ; Wed, 25 Aug 2021 21:40:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2354961101 for ; Wed, 25 Aug 2021 21:40:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234816AbhHYVl0 (ORCPT ); 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Wed, 25 Aug 2021 21:40:34 +0000 (UTC) Received: from llong.com (unknown [10.22.18.37]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1A19B6A056; Wed, 25 Aug 2021 21:40:33 +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 v7 5/6] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Date: Wed, 25 Aug 2021 17:37:49 -0400 Message-Id: <20210825213750.6933-6-longman@redhat.com> In-Reply-To: <20210825213750.6933-1-longman@redhat.com> References: <20210825213750.6933-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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 | 112 +++++++++++++----------- 1 file changed, 63 insertions(+), 49 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index babbe04c8d37..e759b0898bce 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -2091,8 +2091,9 @@ 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 @@ -2101,64 +2102,77 @@ 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. 2) The parent cgroup is a partition root. - 3) The "cpuset.cpus" is also a proper subset of the parent's + 3) The "cpuset.cpus" is a subset of the parent's "cpuset.cpus.effective". 4) There is no child cgroups with cpuset enabled. This is for 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 - file cannot be reverted back to "member" if there are any child + 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 + should not 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. - - 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. - - 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. - - ============== ============================== - "member" Non-root member of a partition - "root" Partition root - "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 parent partition may distribute all its CPUs to its child + partitions as long as it is not the root cgroup. + + Once becoming a partition root, changes to "cpuset.cpus" + is generally allowed as long as the first condition above + (cpu exclusivity rule) is true. + + Sometimes, changes to "cpuset.cpus" or cpu hotplug may cause + the state of the partition root to become invalid when the + other constraints of partition root are violated. Therefore, + user space agents that manage partition roots should avoid + unnecessary changes to "cpuset.cpus" and monitor the state of + "cpuset.cpus.partition" to make sure that the partitions are + functioning as expected. + + 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 + ====================== ============================== + + 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. "" is a string that describes why + the partition becomes invalid. + + An invalid partition is not a real partition even though some + internal states may still be kept. 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 reverted 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. + + Poll and inotify events are triggered whenever the state of + "cpuset.cpus.partition" changes. That includes changes caused by + write to "cpuset.cpus.partition", cpu hotplug and other changes + that make the partition invalid. This will allow user space + agents to monitor unexpected changes to "cpuset.cpus.partition" + without the need to do continuous polling. Device controller From patchwork Wed Aug 25 21:37:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12458575 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=-16.5 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=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ABD91C4320E for ; Wed, 25 Aug 2021 21:40:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9387361214 for ; Wed, 25 Aug 2021 21:40:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234655AbhHYVlc (ORCPT ); Wed, 25 Aug 2021 17:41:32 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:24457 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234874AbhHYVl2 (ORCPT ); Wed, 25 Aug 2021 17:41:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1629927642; 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=JxwYefpVY+75mDp7prbLnHNzE/MBqiMwp+7CZDNLyDM=; b=OMA+lC67bhZwktvUXrJa49UNg30bmdWYrUXnDWuWHx7+I/U1s3axI2FglsIh5NTjL3ChBP DlMEr11Gcat1bO1QrMN63eXh+cmKFWsHGJ8OrJ0qwG60zr2+APX7b4ORCeFNxJlQNJVfWZ bkvMxOtqZ1DWvvubbXmkf7jIw4Jw34s= 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-460-6xZW9Cb6MlS0B9qnKYceAg-1; Wed, 25 Aug 2021 17:40:38 -0400 X-MC-Unique: 6xZW9Cb6MlS0B9qnKYceAg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D6096100E421; Wed, 25 Aug 2021 21:40:36 +0000 (UTC) Received: from llong.com (unknown [10.22.18.37]) by smtp.corp.redhat.com (Postfix) with ESMTP id 148456A056; Wed, 25 Aug 2021 21:40:34 +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 v7 6/6] kselftest/cgroup: Add cpuset v2 partition root state test Date: Wed, 25 Aug 2021 17:37:50 -0400 Message-Id: <20210825213750.6933-7-longman@redhat.com> In-Reply-To: <20210825213750.6933-1-longman@redhat.com> References: <20210825213750.6933-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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 | 663 ++++++++++++++++++ tools/testing/selftests/cgroup/wait_inotify.c | 87 +++ 3 files changed, 753 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..07c4a6ef3700 --- /dev/null +++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh @@ -0,0 +1,663 @@ +#!/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 and delay factor +PROG=$1 +VERBOSE= +DELAY_FACTOR=1 +while [[ "$1" = -* ]] +do + case "$1" in + -v) VERBOSE=1 + break + ;; + -d) DELAY_FACTOR=$2 + shift + break + ;; + *) echo "Usage: $PROG [-v] [-d " + exit + ;; + esac + shift +done + +cd $CGROUP2 +echo +cpuset > cgroup.subtree_control +[[ -d test ]] || mkdir test +cd test + +# Pause in ms +pause() +{ + DELAY=$1 + LOOP=0 + while [[ $LOOP -lt $DELAY_FACTOR ]] + do + sleep $DELAY + ((LOOP++)) + done + return 0 +} + +console_msg() +{ + MSG=$1 + echo "$MSG" + echo "" > /dev/console + echo "$MSG" > /dev/console + pause 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,A2:2 A1:P1,A2:P-1" + " 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,A3:2 A1:P1,A2:P1,A3:P-1" + " 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 + # ---- ------ ------ ------ ------ ------ ------ ------ ------ ---- ----- ------ + # + # Incorrect change to cpuset.cpus invalidates partition root + # + # Adding CPUs to partition root that are not in parent's + # cpuset.cpus.effective makes it invalid. + " S+ C2-3:P1:S+ C3:P1 . . . C2-4 . . 0 A1:2-3,A2:2-3 A1:P1,A2:P-1" + + # Taking away all CPUs from parent or itself if there are tasks + # will make the partition invalid. + " S+ C2-3:P1:S+ C3:P1 . . T C2-3 . . 0 A1:2-3,A2:2-3 A1:P1,A2:P-1" + " S+ $SETUP_A123_PARTITIONS . T:C2-3 . . . 0 A1:2-3,A2:2-3,A3:3 A1:P1,A2:P-1,A3:P-1" + " S+ $SETUP_A123_PARTITIONS . T:C2-3:C1-3 . . . 0 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1" + + # Changing a partition root member invalidates child partitions + " S+ C2-3:P1:S+ C3:P1 . . P0 . . . 0 A1:2-3,A2:3 A1:P0,A2:P-1" + " S+ $SETUP_A123_PARTITIONS . C2-3 P0 . . 0 A1:2-3,A2:2-3,A3:3 A1:P1,A2:P0,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 " + + # A task cannot be added to a non-terminal partition with no cpu + " S+ C2-3:P1:S+ C3:P1 . . O2-0:T . . . 1 A1:,A2:3 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 + pause 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 partition 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 + } + pause 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- + pause 0.01 +} + +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 + CPULIST=0-6 + I=0 + 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]}\" + dump_states + 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 + # + # Check to see if effective cpu list changes + # + pause 0.05 + NEWLIST=$(cat cpuset.cpus.effective) + [[ $NEWLIST != $CPULIST ]] && { + echo "Effective cpus changed to $NEWLIST after test $I!" + exit 1 + } + [[ -n "$VERBOSE" ]] && echo "Test $I done." + ((I++)) + done + echo "All $I tests of $TEST PASSED." + + 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 + } + + pause 0.01 + echo 1 > cpuset.cpus + echo 0 > cgroup.procs + echo root > cpuset.cpus.partition + pause 0.01 + rm -f $PRS + wait_inotify $PWD/cpuset.cpus.partition $PRS & + pause 0.01 + set_ctrl_state . "O1-0" + pause 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..e11b431e1b62 --- /dev/null +++ b/tools/testing/selftests/cgroup/wait_inotify.c @@ -0,0 +1,87 @@ +// 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 + +static const char usage[] = "Usage: %s [-v] \n"; +static char *file; +static int verbose; + +static inline void fail_message(char *msg) +{ + fprintf(stderr, msg, file); + exit(1); +} + +int main(int argc, char *argv[]) +{ + char *cmd = argv[0]; + int c, fd; + struct pollfd fds = { .events = POLLIN, }; + + while ((c = getopt(argc, argv, "v")) != -1) { + switch (c) { + case 'v': + verbose++; + break; + } + argv++, argc--; + } + + 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_add_watch() 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; + } + if (verbose) { + struct inotify_event events[10]; + long len; + + usleep(1000); + len = read(fd, events, sizeof(events)); + printf("Number of events read = %ld\n", + len/sizeof(struct inotify_event)); + } + close(fd); + return 0; +}