From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A019137D137; Fri, 3 Jul 2026 08:02:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783065733; cv=none; b=WvNyGcvj94dLpvHv7MgOp5TINKf350gxIaoONA44DY7lQn11ptmXpVLaYTMaVtYtjgJWCqIrkOhfCTCfEUz33XeTPkSDZJhAuDNo8yewy4vKrDOGHJixijCDHDMzzqasgB+lOftWKJ1KqESiZYsSKXbeaYzjxq1pU3010olvkQk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783065733; c=relaxed/simple; bh=0TIM1F3Q3Nhb+vyuPksjtaJeWoqSOZQGJP85GkSub9w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DYY0WFlamXDR57GyUmfGkWeTkcenqeRgk2bPPVHhxmQWttT7dNy2G313RHLQGXezrZarGw5jm4hucYnf/8kxOknWJVIcYKP6DxNPEmEiRgrUiXnM6LNi9bF0WSwpeG/RCih5wMm6p9MkitgtkX9ASbELSFhmPQovkaTYfTWCSfQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XXbsFidv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XXbsFidv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E0981F000E9; Fri, 3 Jul 2026 08:02:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783065731; bh=6HiHT0a7L7FHYa7qUnKc6LBIIc0A5qcu1vD8yHRmmUA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=XXbsFidvXF9AAFKhNDFLkHjEUUDSolyhaqu8+0Ld0wBq6embilgzEYFKa7S8LWYJA kacJOUcUb5W35FcIErBUxuE+ICGN1W3y25oD+R2xELP1pprdeMCjsNf+zOj7lNv7lM 2GoEbSXiMYZ/a2Hh0kIC2DGw5u/ueUnpPUD1As/YFn1gifBrC3HfjTEmm8E/y07da5 WfH/WgtNTaOkmNcvqZTcA3i85KlxQxBEkVvBTLU3pw4Sw2ZkOkT9SgIjfDxnU5EtKo UyTDU6+C6q3yl8+8RrhXu3kYvcJZlT/B15gmSutWIbOcoyAI/OcTMj1x6MnY5MORQx tplXXq8ZOw3FA== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min Cc: sched-ext@lists.linux.dev, Emil Tsalapatis , linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH sched_ext/for-7.3 11/32] sched_ext: Defer scx_sched kobj sysfs add into the enable workfns Date: Thu, 2 Jul 2026 22:01:38 -1000 Message-ID: <20260703080159.2314350-12-tj@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260703080159.2314350-1-tj@kernel.org> References: <20260703080159.2314350-1-tj@kernel.org> Precedence: bulk X-Mailing-List: sched-ext@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Split kobject_init_and_add() in scx_alloc_and_add_sched(): only kobject_init() runs there. A new scx_sched_sysfs_add() helper does kobject_add() (and creates sub_kset when the scheduler implements ops.sub_attach), called by both enable workfns once @sch is linked and its sysfs-visible state is initialized. Prep so a future caps attribute can rely on @sch being fully built by the time it's sysfs-visible. Add early enough that a stall later in enable still leaves sysfs inspectable. Signed-off-by: Tejun Heo --- kernel/sched/ext/ext.c | 73 +++++++++++++++++++++++-------------- kernel/sched/ext/internal.h | 1 + kernel/sched/ext/sub.c | 8 +++- 3 files changed, 53 insertions(+), 29 deletions(-) diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index 87a3fb9bb446..fcb8bf0d2422 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -5704,7 +5704,9 @@ static void scx_root_disable(struct scx_sched *sch) if (sch->sub_kset) kobject_del(&sch->sub_kset->kobj); #endif - kobject_del(&sch->kobj); + /* not added if enable failed before scx_sched_sysfs_add() */ + if (sch->kobj.state_in_sysfs) + kobject_del(&sch->kobj); free_kick_syncs(); @@ -6421,36 +6423,15 @@ struct scx_sched *scx_alloc_and_add_sched(struct scx_enable_cmd *cmd, * disable. Released in scx_sched_free_rcu_work(). */ kobject_get(&parent->kobj); - ret = kobject_init_and_add(&sch->kobj, &scx_ktype, - &parent->sub_kset->kobj, - "sub-%llu", cgroup_id(cgrp)); - } else { - ret = kobject_init_and_add(&sch->kobj, &scx_ktype, NULL, "root"); - } - - if (ret < 0) { - RCU_INIT_POINTER(ops->priv, NULL); - kobject_put(&sch->kobj); - return ERR_PTR(ret); - } - - if (ops->sub_attach) { - sch->sub_kset = kset_create_and_add("sub", NULL, &sch->kobj); - if (!sch->sub_kset) { - RCU_INIT_POINTER(ops->priv, NULL); - kobject_put(&sch->kobj); - return ERR_PTR(-ENOMEM); - } - } -#else /* CONFIG_EXT_SUB_SCHED */ - ret = kobject_init_and_add(&sch->kobj, &scx_ktype, NULL, "root"); - if (ret < 0) { - RCU_INIT_POINTER(ops->priv, NULL); - kobject_put(&sch->kobj); - return ERR_PTR(ret); } #endif /* CONFIG_EXT_SUB_SCHED */ + /* + * Init the kobj but don't add to sysfs yet. The enable path calls + * scx_sched_sysfs_add() once @sch's sysfs-visible state is initialized. + */ + kobject_init(&sch->kobj, &scx_ktype); + /* * Consume the arena_map ref bpf_scx_reg_cid() took. Defer to here so * earlier failure paths leave cmd->arena_map set and bpf_scx_reg_cid @@ -6508,6 +6489,36 @@ struct scx_sched *scx_alloc_and_add_sched(struct scx_enable_cmd *cmd, return ERR_PTR(ret); } +/* + * Add @sch's kobject to sysfs, and create its sub_kset if the scheduler + * implements ops.sub_attach. Called by the enable workfns once @sch's + * sysfs-visible state is initialized. + */ +int scx_sched_sysfs_add(struct scx_sched *sch) +{ +#ifdef CONFIG_EXT_SUB_SCHED + struct scx_sched *parent = scx_parent(sch); + int ret; + + if (parent) + ret = kobject_add(&sch->kobj, &parent->sub_kset->kobj, + "sub-%llu", cgroup_id(sch_cgroup(sch))); + else + ret = kobject_add(&sch->kobj, NULL, "root"); + if (ret < 0) + return ret; + + if (sch->ops.sub_attach) { + sch->sub_kset = kset_create_and_add("sub", NULL, &sch->kobj); + if (!sch->sub_kset) + return -ENOMEM; + } + return 0; +#else + return kobject_add(&sch->kobj, NULL, "root"); +#endif +} + static int check_hotplug_seq(struct scx_sched *sch, const struct sched_ext_ops *ops) { @@ -6730,6 +6741,12 @@ static void scx_root_enable_workfn(struct kthread_work *work) sch->exit_info->flags |= SCX_EFLAG_INITIALIZED; } + ret = scx_sched_sysfs_add(sch); + if (ret) { + cpus_read_unlock(); + goto err_disable; + } + for (i = SCX_OPI_CPU_HOTPLUG_BEGIN; i < SCX_OPI_CPU_HOTPLUG_END; i++) if (((void (**)(void))ops)[i]) set_bit(i, sch->has_op); diff --git a/kernel/sched/ext/internal.h b/kernel/sched/ext/internal.h index ba5e9be0e3c3..7c6f4ed10cde 100644 --- a/kernel/sched/ext/internal.h +++ b/kernel/sched/ext/internal.h @@ -1689,6 +1689,7 @@ struct scx_sched *scx_alloc_and_add_sched(struct scx_enable_cmd *cmd, struct cgroup *cgrp, struct scx_sched *parent); int scx_validate_ops(struct scx_sched *sch, const struct sched_ext_ops *ops); +int scx_sched_sysfs_add(struct scx_sched *sch); extern raw_spinlock_t scx_sched_lock; extern struct mutex scx_enable_mutex; diff --git a/kernel/sched/ext/sub.c b/kernel/sched/ext/sub.c index 050420427273..e94a415ee10a 100644 --- a/kernel/sched/ext/sub.c +++ b/kernel/sched/ext/sub.c @@ -270,7 +270,9 @@ void scx_sub_disable(struct scx_sched *sch) SCX_CALL_OP(sch, exit, NULL, sch->exit_info); if (sch->sub_kset) kobject_del(&sch->sub_kset->kobj); - kobject_del(&sch->kobj); + /* not added if enable failed before scx_sched_sysfs_add() */ + if (sch->kobj.state_in_sysfs) + kobject_del(&sch->kobj); } /* verify that a scheduler can be attached to @cgrp and return the parent */ @@ -363,6 +365,10 @@ void scx_sub_enable_workfn(struct kthread_work *work) if (ret) goto err_disable; + ret = scx_sched_sysfs_add(sch); + if (ret) + goto err_disable; + if (sch->level >= SCX_SUB_MAX_DEPTH) { scx_error(sch, "max nesting depth %d violated", SCX_SUB_MAX_DEPTH); -- 2.54.0