From nobody Sat Apr 11 17:23:19 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B31C9C678D5 for ; Wed, 8 Mar 2023 13:19:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230110AbjCHNTD (ORCPT ); Wed, 8 Mar 2023 08:19:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43414 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231435AbjCHNS2 (ORCPT ); Wed, 8 Mar 2023 08:18:28 -0500 Received: from mail-wm1-x34a.google.com (mail-wm1-x34a.google.com [IPv6:2a00:1450:4864:20::34a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9558160A81 for ; Wed, 8 Mar 2023 05:15:07 -0800 (PST) Received: by mail-wm1-x34a.google.com with SMTP id m31-20020a05600c3b1f00b003e9de8c95easo5861816wms.2 for ; Wed, 08 Mar 2023 05:15:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1678281305; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=geKZ0b9prEjt0Vyx6WHp2kYThqOYNTypo8c4MCHr/Ug=; b=htYNEPtk6BdX8z3OZd8E1kcZH+GqH/PCqaiMJMhmag7qj17psAkY2Q4aOOaLwjtnKA ICKCRsPwtxEk2RNuOTIBzhMA1Mt+gL91pBWSMnnb/hZhK5eR+5irRQ394J1SuHaRRivX 2RniGgFV5szp0oEbB1EmyNEweQaK2vHlHyMQi6pVlQP0lBxP53m0WvQheg9e6AIIyv7g 9ZrVgv/xplCIwomQ2sIwvZW3P6V8VMF0JxHIMBX4cJjdMi4mtmY+z3fdEn1+9Oyn1kcz X4HAN3S6l/Y85mtD4ZMZic7/xgPPDaIN58ioUIRx5QMh3VK14D+BufUr1a0h5R2Otf/2 31sg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678281305; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=geKZ0b9prEjt0Vyx6WHp2kYThqOYNTypo8c4MCHr/Ug=; b=38X34LkOqMktEvrzfnicyJ0vwLaqDgO4CGb3/QhzWOZmlOqB8lAksx687/w/XEtUTy yvTTksGWcA+LVJuXTNpLCmKLQuqxOl6BqajatfTs7TM9j5Tu6+CaX3Sjbacv6vW9dL2Y RXUqOh3JGwf3PXdPjfr5UAr++dUKOVMpxwMhgFL14cieBTGYgqvGytdn4yr9PmfTgGiL /oPEZ2HiDih8gcV6wasscqB/SX5AXse4kQYYNizNRf/FczDH1HHAqKgFLM4Kz7vArKb/ n+fWgvPB9xOm+FGGrhRenrxLqsAoJQnSb8Nw1y5LvyMBhEt9rPsaBUk1Y6J20jtwEr5u X1zQ== X-Gm-Message-State: AO0yUKWzyzyoJfZVQMVQZOJJg8LRkjTgc5u2h69D7dT2SVkxExLWseyW QaFLJUKHtrGSWZb71mJ998Ms9d7YYtGB6F0JfQ== X-Google-Smtp-Source: AK7set/d3HjzTgsMqD9lr8qdZINBXsOe+YOvLtFpbnHdwJj+9iGVz8gC4oUpjeqi7T8S/Lx4gTwbMfv8Y/THdYqPZw== X-Received: from peternewman-vh.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:30cc]) (user=peternewman job=sendgmr) by 2002:a5d:608a:0:b0:2c8:2cbc:7a2e with SMTP id w10-20020a5d608a000000b002c82cbc7a2emr3545133wrt.4.1678281305672; Wed, 08 Mar 2023 05:15:05 -0800 (PST) Date: Wed, 8 Mar 2023 14:14:50 +0100 In-Reply-To: <20230308131452.383914-1-peternewman@google.com> Mime-Version: 1.0 References: <20230308131452.383914-1-peternewman@google.com> X-Mailer: git-send-email 2.40.0.rc0.216.gc4246ad0f0-goog Message-ID: <20230308131452.383914-2-peternewman@google.com> Subject: [PATCH v4 1/3] x86/resctrl: Factor rdtgroup lock for multi-file ops From: Peter Newman To: reinette.chatre@intel.com, fenghua.yu@intel.com Cc: Babu.Moger@amd.com, bp@alien8.de, dave.hansen@linux.intel.com, eranian@google.com, gupasani@google.com, hpa@zytor.com, james.morse@arm.com, linux-kernel@vger.kernel.org, mingo@redhat.com, skodak@google.com, tglx@linutronix.de, tony.luck@intel.com, x86@kernel.org, Peter Newman Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" rdtgroup_kn_lock_live() can only release a kernfs reference for a single file before waiting on the rdtgroup_mutex, limiting its usefulness for operations on multiple files, such as rename. Factor the work needed to respectively break and unbreak active protection on an individual file into rdtgroup_kn_{get,put}(). No functional change. Signed-off-by: Peter Newman Reviewed-by: Reinette Chatre --- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 35 ++++++++++++++++---------- 1 file changed, 22 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/r= esctrl/rdtgroup.c index 5993da21d822..c3fb525d52e9 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -2028,6 +2028,26 @@ static struct rdtgroup *kernfs_to_rdtgroup(struct ke= rnfs_node *kn) } } =20 +static void rdtgroup_kn_get(struct rdtgroup *rdtgrp, struct kernfs_node *k= n) +{ + atomic_inc(&rdtgrp->waitcount); + kernfs_break_active_protection(kn); +} + +static void rdtgroup_kn_put(struct rdtgroup *rdtgrp, struct kernfs_node *k= n) +{ + if (atomic_dec_and_test(&rdtgrp->waitcount) && + (rdtgrp->flags & RDT_DELETED)) { + if (rdtgrp->mode =3D=3D RDT_MODE_PSEUDO_LOCKSETUP || + rdtgrp->mode =3D=3D RDT_MODE_PSEUDO_LOCKED) + rdtgroup_pseudo_lock_remove(rdtgrp); + kernfs_unbreak_active_protection(kn); + rdtgroup_remove(rdtgrp); + } else { + kernfs_unbreak_active_protection(kn); + } +} + struct rdtgroup *rdtgroup_kn_lock_live(struct kernfs_node *kn) { struct rdtgroup *rdtgrp =3D kernfs_to_rdtgroup(kn); @@ -2035,8 +2055,7 @@ struct rdtgroup *rdtgroup_kn_lock_live(struct kernfs_= node *kn) if (!rdtgrp) return NULL; =20 - atomic_inc(&rdtgrp->waitcount); - kernfs_break_active_protection(kn); + rdtgroup_kn_get(rdtgrp, kn); =20 mutex_lock(&rdtgroup_mutex); =20 @@ -2055,17 +2074,7 @@ void rdtgroup_kn_unlock(struct kernfs_node *kn) return; =20 mutex_unlock(&rdtgroup_mutex); - - if (atomic_dec_and_test(&rdtgrp->waitcount) && - (rdtgrp->flags & RDT_DELETED)) { - if (rdtgrp->mode =3D=3D RDT_MODE_PSEUDO_LOCKSETUP || - rdtgrp->mode =3D=3D RDT_MODE_PSEUDO_LOCKED) - rdtgroup_pseudo_lock_remove(rdtgrp); - kernfs_unbreak_active_protection(kn); - rdtgroup_remove(rdtgrp); - } else { - kernfs_unbreak_active_protection(kn); - } + rdtgroup_kn_put(rdtgrp, kn); } =20 static int mkdir_mondata_all(struct kernfs_node *parent_kn, --=20 2.40.0.rc0.216.gc4246ad0f0-goog From nobody Sat Apr 11 17:23:19 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 770EEC678D5 for ; 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Wed, 08 Mar 2023 05:15:08 -0800 (PST) Date: Wed, 8 Mar 2023 14:14:51 +0100 In-Reply-To: <20230308131452.383914-1-peternewman@google.com> Mime-Version: 1.0 References: <20230308131452.383914-1-peternewman@google.com> X-Mailer: git-send-email 2.40.0.rc0.216.gc4246ad0f0-goog Message-ID: <20230308131452.383914-3-peternewman@google.com> Subject: [PATCH v4 2/3] x86/resctrl: Parameterize rdt_move_group_tasks() task matching From: Peter Newman To: reinette.chatre@intel.com, fenghua.yu@intel.com Cc: Babu.Moger@amd.com, bp@alien8.de, dave.hansen@linux.intel.com, eranian@google.com, gupasani@google.com, hpa@zytor.com, james.morse@arm.com, linux-kernel@vger.kernel.org, mingo@redhat.com, skodak@google.com, tglx@linutronix.de, tony.luck@intel.com, x86@kernel.org, Peter Newman Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Allow rdt_move_group_tasks() to be used for new group-scope operations. This function is currently only used to implement rmdir on a group or unmounting resctrlfs. Callers now provide a filtering function to indicate which tasks should be moved. No functional change. Signed-off-by: Peter Newman --- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 34 +++++++++++++++++++------- 1 file changed, 25 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/r= esctrl/rdtgroup.c index c3fb525d52e9..84af23a29612 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -2393,22 +2393,29 @@ static int reset_all_ctrls(struct rdt_resource *r) } =20 /* - * Move tasks from one to the other group. If @from is NULL, then all tasks - * in the systems are moved unconditionally (used for teardown). + * Move tasks from one to the other group. + * + * @from: passed unmodified to task_match_fn() for each task + * @to: group providing new config values for matching tasks + * @task_match_fn: callback returning true when a task requires update + * @mask: output-parameter indicating set of CPUs impacted by this + * operation * * If @mask is not NULL the cpus on which moved tasks are running are set * in that mask so the update smp function call is restricted to affected * cpus. */ -static void rdt_move_group_tasks(struct rdtgroup *from, struct rdtgroup *t= o, - struct cpumask *mask) +static void rdt_move_group_tasks(struct rdtgroup *from, + struct rdtgroup *to, + struct cpumask *mask, + bool task_match_fn(struct task_struct *, + struct rdtgroup *)) { struct task_struct *p, *t; =20 read_lock(&tasklist_lock); for_each_process_thread(p, t) { - if (!from || is_closid_match(t, from) || - is_rmid_match(t, from)) { + if (task_match_fn(t, from)) { WRITE_ONCE(t->closid, to->closid); WRITE_ONCE(t->rmid, to->mon.rmid); =20 @@ -2451,6 +2458,15 @@ static void free_all_child_rdtgrp(struct rdtgroup *r= dtgrp) } } =20 +/* + * If @from is NULL, then all tasks in the systems are moved unconditional= ly + * (used for teardown). + */ +static bool rmdir_match(struct task_struct *t, struct rdtgroup *from) +{ + return !from || is_closid_match(t, from) || is_rmid_match(t, from); +} + /* * Forcibly remove all of subdirectories under root. */ @@ -2459,7 +2475,7 @@ static void rmdir_all_sub(void) struct rdtgroup *rdtgrp, *tmp; =20 /* Move all tasks to the default resource group */ - rdt_move_group_tasks(NULL, &rdtgroup_default, NULL); + rdt_move_group_tasks(NULL, &rdtgroup_default, NULL, rmdir_match); =20 list_for_each_entry_safe(rdtgrp, tmp, &rdt_all_groups, rdtgroup_list) { /* Free any child rmids */ @@ -3124,7 +3140,7 @@ static int rdtgroup_rmdir_mon(struct rdtgroup *rdtgrp= , cpumask_var_t tmpmask) int cpu; =20 /* Give any tasks back to the parent group */ - rdt_move_group_tasks(rdtgrp, prdtgrp, tmpmask); + rdt_move_group_tasks(rdtgrp, prdtgrp, tmpmask, rmdir_match); =20 /* Update per cpu rmid of the moved CPUs first */ for_each_cpu(cpu, &rdtgrp->cpu_mask) @@ -3164,7 +3180,7 @@ static int rdtgroup_rmdir_ctrl(struct rdtgroup *rdtgr= p, cpumask_var_t tmpmask) int cpu; =20 /* Give any tasks back to the default group */ - rdt_move_group_tasks(rdtgrp, &rdtgroup_default, tmpmask); + rdt_move_group_tasks(rdtgrp, &rdtgroup_default, tmpmask, rmdir_match); =20 /* Give any CPUs back to the default group */ cpumask_or(&rdtgroup_default.cpu_mask, --=20 2.40.0.rc0.216.gc4246ad0f0-goog From nobody Sat Apr 11 17:23:19 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54966C678D5 for ; Wed, 8 Mar 2023 13:19:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231348AbjCHNTM (ORCPT ); Wed, 8 Mar 2023 08:19:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231521AbjCHNSc (ORCPT ); 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Wed, 08 Mar 2023 05:15:10 -0800 (PST) Date: Wed, 8 Mar 2023 14:14:52 +0100 In-Reply-To: <20230308131452.383914-1-peternewman@google.com> Mime-Version: 1.0 References: <20230308131452.383914-1-peternewman@google.com> X-Mailer: git-send-email 2.40.0.rc0.216.gc4246ad0f0-goog Message-ID: <20230308131452.383914-4-peternewman@google.com> Subject: [PATCH v4 3/3] x86/resctrl: Implement rename op for mon groups From: Peter Newman To: reinette.chatre@intel.com, fenghua.yu@intel.com Cc: Babu.Moger@amd.com, bp@alien8.de, dave.hansen@linux.intel.com, eranian@google.com, gupasani@google.com, hpa@zytor.com, james.morse@arm.com, linux-kernel@vger.kernel.org, mingo@redhat.com, skodak@google.com, tglx@linutronix.de, tony.luck@intel.com, x86@kernel.org, Peter Newman Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" To change the class of service for a large group of tasks, such as an application container, a container manager must write all of the tasks' IDs into the tasks file interface of the new control group. If a container manager is tracking containers' bandwidth usage by placing tasks from each into their own monitoring group, it must first move the tasks to the default monitoring group of the new control group before it can move the tasks into their new monitoring groups. This is undesirable because it makes bandwidth usage during the move unattributable to the correct tasks and resets monitoring event counters and cache usage information for the group. To address this, implement the rename operation for resctrlfs mon groups to effect a change in CLOSID for a MON group while otherwise leaving the monitoring group intact. Signed-off-by: Peter Newman --- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 127 +++++++++++++++++++++++++ 1 file changed, 127 insertions(+) diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/r= esctrl/rdtgroup.c index 84af23a29612..6d576013fc16 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -3256,6 +3256,132 @@ static int rdtgroup_rmdir(struct kernfs_node *kn) return ret; } =20 +static bool mongrp_reparent_match(struct task_struct *t, struct rdtgroup *= from) +{ + WARN_ON(from->type !=3D RDTMON_GROUP); + + /* RMID match implies CLOSID match. */ + return is_rmid_match(t, from); +} + +/** + * mongrp_reparent() - replace parent CTRL_MON group of a MON group + * @rdtgrp: the MON group whose parent should be replaced + * @new_prdtgrp: replacement parent CTRL_MON group for @rdtgrp + * @cpus: cpumask provided by the caller for use during this call + * + * Replaces the parent CTRL_MON group for a MON group, resulting in all me= mber + * tasks' CLOSID immediately changing to that of the new parent group. + * Monitoring data for the group is unaffected by this operation. + */ +static void mongrp_reparent(struct rdtgroup *rdtgrp, + struct rdtgroup *new_prdtgrp, + cpumask_var_t cpus) +{ + struct rdtgroup *prdtgrp =3D rdtgrp->mon.parent; + + WARN_ON(rdtgrp->type !=3D RDTMON_GROUP); + WARN_ON(new_prdtgrp->type !=3D RDTCTRL_GROUP); + + /* Nothing to do when simply renaming a MON group. */ + if (prdtgrp =3D=3D new_prdtgrp) + return; + + WARN_ON(list_empty(&prdtgrp->mon.crdtgrp_list)); + list_del(&rdtgrp->mon.crdtgrp_list); + + list_add_tail(&rdtgrp->mon.crdtgrp_list, + &new_prdtgrp->mon.crdtgrp_list); + rdtgrp->mon.parent =3D new_prdtgrp; + rdtgrp->closid =3D new_prdtgrp->closid; + + /* Propagate updated closid to all tasks in this group. */ + rdt_move_group_tasks(rdtgrp, rdtgrp, cpus, mongrp_reparent_match); + + update_closid_rmid(cpus, NULL); +} + +static int rdtgroup_rename(struct kernfs_node *kn, + struct kernfs_node *new_parent, const char *new_name) +{ + struct rdtgroup *new_prdtgrp; + struct rdtgroup *rdtgrp; + cpumask_var_t tmpmask; + int ret; + + /* + * Don't allow kernfs_to_rdtgroup() to return a parent rdtgroup if + * either kernfs_node is a file. + */ + if (kernfs_type(kn) !=3D KERNFS_DIR || + kernfs_type(new_parent) !=3D KERNFS_DIR) + return -EPERM; + + rdtgrp =3D kernfs_to_rdtgroup(kn); + new_prdtgrp =3D kernfs_to_rdtgroup(new_parent); + if (!rdtgrp || !new_prdtgrp) + return -EPERM; + + if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL)) + return -ENOMEM; + + /* Release both kernfs active_refs before obtaining rdtgroup mutex. */ + rdtgroup_kn_get(rdtgrp, kn); + rdtgroup_kn_get(new_prdtgrp, new_parent); + + mutex_lock(&rdtgroup_mutex); + + rdt_last_cmd_clear(); + + if ((rdtgrp->flags & RDT_DELETED) || (new_prdtgrp->flags & RDT_DELETED)) { + ret =3D -ESRCH; + goto out; + } + + if (rdtgrp->type !=3D RDTMON_GROUP || !kn->parent || + !is_mon_groups(kn->parent, kn->name)) { + rdt_last_cmd_puts("source must be a MON group\n"); + ret =3D -EPERM; + goto out; + } + + if (!is_mon_groups(new_parent, new_name)) { + rdt_last_cmd_puts("destination must be a mon_groups subdirectory\n"); + ret =3D -EPERM; + goto out; + } + + /* + * If the MON group is monitoring CPUs, they must be assigned to the + * current parent CTRL_MON group and therefore cannot be assigned to + * the new parent, making the move illegal. + */ + if (!cpumask_empty(&rdtgrp->cpu_mask) && + (rdtgrp->mon.parent !=3D new_prdtgrp)) { + rdt_last_cmd_puts("cannot move a MON group that monitors CPUs\n"); + ret =3D -EPERM; + goto out; + } + + /* + * Perform all input validation needed to ensure mongrp_reparent() will + * succeed before calling kernfs_rename(), otherwise it would be + * necessary to revert this call if mongrp_reparent() failed. + */ + ret =3D kernfs_rename(kn, new_parent, new_name); + if (ret) + goto out; + + mongrp_reparent(rdtgrp, new_prdtgrp, tmpmask); + +out: + mutex_unlock(&rdtgroup_mutex); + rdtgroup_kn_put(rdtgrp, kn); + rdtgroup_kn_put(new_prdtgrp, new_parent); + free_cpumask_var(tmpmask); + return ret; +} + static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root = *kf) { if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3)) @@ -3273,6 +3399,7 @@ static int rdtgroup_show_options(struct seq_file *seq= , struct kernfs_root *kf) static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops =3D { .mkdir =3D rdtgroup_mkdir, .rmdir =3D rdtgroup_rmdir, + .rename =3D rdtgroup_rename, .show_options =3D rdtgroup_show_options, }; =20 --=20 2.40.0.rc0.216.gc4246ad0f0-goog