From nobody Mon Apr 13 17:09:04 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 E440FC433FE for ; Tue, 15 Nov 2022 15:45:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238284AbiKOPpy (ORCPT ); Tue, 15 Nov 2022 10:45:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231347AbiKOPps (ORCPT ); Tue, 15 Nov 2022 10:45:48 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 779FF10565 for ; Tue, 15 Nov 2022 07:45:47 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-370624ca2e8so138944817b3.16 for ; Tue, 15 Nov 2022 07:45:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=cUFeRtZYB7UeTgxIn2ZhYMocLTGExrmRKO4xcP78LzE=; b=Si5zz34w8W5OUKEmuwma1mET23o1UNMM0e+o9fGg5w5QBLXN0EQOINeapJXw0xkhN5 jIBGAQpEgsaEeu2F7RJfTUTekBnD5xmh7oO3DT9e/g5GH9xCDINR/nnIH1JQBtjCA8Ky cGd2mkkePepc9zsCKoQBhNWoANyqmXIHeOPNSUqILXJ+JDo0m+Fg58+w9dEi+qyzv9PK mkkEjCyPJL2UD0KfMddbIdEX6IIwT+BCGM1qp7vQZJ89JXMBRgZua0U4jSF0TfY/8A3L P5OCi+bq6OzDA/4TybR/avT7cMQ6ZUIN1MQpCKdkmJhl6PAQflUILq9El2VnyO7VmIPI Ckig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=cUFeRtZYB7UeTgxIn2ZhYMocLTGExrmRKO4xcP78LzE=; b=UAoHqmIwUjv6pmHoHfLUzdnwzEEavYeH5PIg7sBNDDyfPF/szhhHAxawbSnelet5v9 z0C+rTMXMmMjyT+TW96ti0hrcMVK7WPJFJGkZqJWXx9oenxvbYNyHvw2uuDnntNLVeJr r4hN+leZO8qlwdt0o+9sr6ouXLGjrUhTAC6umz2gpNxv1hIXIdYj/G6wvKdNUvvbUKHK 7sBOQuExuKbLpKo7OAjBcxD910I9MbGVJ7oTkOoQfTHCzbevutu17iH+xWVSAiWUDy3C VafdGZfURm6GY7nByFRNSSM9fgGzQqgnsukO1BlRo8HPwk7WzopofWAry5rP+/Dam4+q 37FA== X-Gm-Message-State: ANoB5pmqsQSnvWCN+RWeDRP6OajdBGKggHz8xkbxLT2QpE5PV+NWQmG5 qP4LYytun7sphLNWJfh6IIc18IJgS/0egFZvPg== X-Google-Smtp-Source: AA0mqf69A0hZw4IJg/9Hpym+IBCNApy2UjMUCdqSJlD8FX/eyVqv53ZuVqcM51FoPNf2fzyMh+wKHprvlaeRH4bg9Q== X-Received: from peternewman10.zrh.corp.google.com ([2a00:79e0:9d:6:fe62:9ede:ae13:6fda]) (user=peternewman job=sendgmr) by 2002:a25:40ce:0:b0:6d5:34ad:10c5 with SMTP id n197-20020a2540ce000000b006d534ad10c5mr28033116yba.494.1668527146292; Tue, 15 Nov 2022 07:45:46 -0800 (PST) Date: Tue, 15 Nov 2022 16:45:14 +0100 In-Reply-To: <20221115154515.952783-1-peternewman@google.com> Mime-Version: 1.0 References: <20221115154515.952783-1-peternewman@google.com> X-Mailer: git-send-email 2.38.1.493.g58b659f92b-goog Message-ID: <20221115154515.952783-2-peternewman@google.com> Subject: [PATCH v1 1/2] x86/resctrl: factor rdtgroup lock for multi-file ops From: Peter Newman To: Fenghua Yu , Reinette Chatre Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , James Morse , Stephane Eranian , Gaurang Upasani , Babu Moger , linux-kernel@vger.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 help implement kernfs 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}(). The existing rdtgroup_kn_lock_live() could only release the kernfs lock for a single file before waiting on the rdtgroup_mutex. This refactoring should not result in any functional change. Signed-off-by: Peter Newman --- 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 e5a48f05e787..03b51543c26d 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -2026,6 +2026,26 @@ 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); @@ -2033,8 +2053,7 @@ 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 @@ -2053,17 +2072,7 @@ 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 2.38.1.493.g58b659f92b-goog From nobody Mon Apr 13 17:09:04 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 030E4C433FE for ; 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Tue, 15 Nov 2022 07:45:51 -0800 (PST) Date: Tue, 15 Nov 2022 16:45:15 +0100 In-Reply-To: <20221115154515.952783-1-peternewman@google.com> Mime-Version: 1.0 References: <20221115154515.952783-1-peternewman@google.com> X-Mailer: git-send-email 2.38.1.493.g58b659f92b-goog Message-ID: <20221115154515.952783-3-peternewman@google.com> Subject: [PATCH v1 2/2] x86/resctrl: Implement rename op for mon groups From: Peter Newman To: Fenghua Yu , Reinette Chatre Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , James Morse , Stephane Eranian , Gaurang Upasani , Babu Moger , linux-kernel@vger.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" Implement the rename operation for resctrlfs mon groups to effect a change in CLOSID for a MON group while otherwise leaving the group intact. This operation is useful as a solution to changing the class of service of a running container without impacting its resource usage counters on systems which do not implement enough CLOSIDs to give every container it's own CTRL_MON group. Previously, on such systems, it would have been necessary to move every task individually to a new CTRL_MON group using the tasks file. This approach races with the creation of new tasks in the group, making it practically unusable. It's important to note that this solution relies on the fact that Intel and AMD hardware allow the RMID to be assigned independently of the CLOSID. Without this, this operation may not be as useful. Signed-off-by: Peter Newman --- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 66 ++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/r= esctrl/rdtgroup.c index 03b51543c26d..d6562d98b816 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -3230,6 +3230,71 @@ static int rdtgroup_rmdir(struct kernfs_node *kn) return ret; } =20 +static void mongrp_move(struct rdtgroup *rdtgrp, struct rdtgroup *new_prdt= grp) +{ + struct rdtgroup *prdtgrp =3D rdtgrp->mon.parent; + struct task_struct *p, *t; + + 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; + + read_lock(&tasklist_lock); + for_each_process_thread(p, t) { + if (is_closid_match(t, prdtgrp) && is_rmid_match(t, rdtgrp)) + WRITE_ONCE(t->closid, new_prdtgrp->closid); + } + read_unlock(&tasklist_lock); + + update_closid_rmid(cpu_online_mask, 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; + int ret; + + rdtgrp =3D kernfs_to_rdtgroup(kn); + new_prdtgrp =3D kernfs_to_rdtgroup(new_parent); + if (!rdtgrp || !new_prdtgrp) + return -EPERM; + + /* 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); + + if ((rdtgrp->flags & RDT_DELETED) || (new_prdtgrp->flags & RDT_DELETED)) { + ret =3D -ESRCH; + goto out; + } + + /* Only a mon group can be moved to a new mon_groups directory. */ + if (rdtgrp->type !=3D RDTMON_GROUP || + !is_mon_groups(new_parent, kn->name)) { + ret =3D -EPERM; + goto out; + } + + ret =3D kernfs_rename(kn, new_parent, new_name); + if (ret) + goto out; + + mongrp_move(rdtgrp, new_prdtgrp); + +out: + mutex_unlock(&rdtgroup_mutex); + rdtgroup_kn_put(rdtgrp, kn); + rdtgroup_kn_put(new_prdtgrp, new_parent); + return ret; +} + static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root = *kf) { if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3)) @@ -3247,6 +3312,7 @@ 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 2.38.1.493.g58b659f92b-goog