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 717F03B6C11; Thu, 9 Jul 2026 22:50:49 +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=1783637452; cv=none; b=njNHG5xMXDkkF/tNoJ2XP6XqrPVf/A7RrqKZrMN+uApxiuC0bOeHiacjqJ1ViDbM5cYhGcox2BXPmvBbpwgqMNptsOtM/BEs21xL/4Eu3muwdTS/SjpzJO4Kd5ewQPBPi2bMGBQGsrMTQOZm7DJZkTwmergewEXcf8s6D3Al40A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783637452; c=relaxed/simple; bh=sBHRQqTTNh6M7vrvx8kuJ/6C79oci0xQBUcbNyeB4SE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CofnQ27SBfyLhfWo0thdvSV4FRqWb9B1L87LkbcPdueEBlLNwJ7PklB6FSVjACK/rYVXYiyzAIJBXFFTKObwbphy9UK6bvrlfT/xwQHOJa3BNi/Bf1a00v9Qks6YrUx8OLl3DSuxxgNGw/veTWKsoNV369ObETS4XLOJLolMlAM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gYbF1DmG; 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="gYbF1DmG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23B181F00A3A; Thu, 9 Jul 2026 22:50:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783637449; bh=woW66gU/hP00xAr9Z8yWU4emvNhq6+s4HTd02MWvyI8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gYbF1DmGrfB5KMyH4TYOmGB0z82cgV+0LpteQKE4KGnejgg8V4QHTOpoRmn3LzQ3+ rn/HtREnQY72oPnIXj3/W5x8MuNAC56Pr4+FxIgW+dsAeVGIant3d3/UOIRznbIbxu scc7lOiNHYwwt7A166wlCBgDzGFmvf9kvBuw8q+e9qbz8+caLKyOrLpsaaX4grfQ4H W7nfRczz9MiCKIj1xpjEZUnHMiQ9GlvtC+JK+fU10oecZNtG+d9UWPwX5xLkFotimm a5OV/4+rP7WVjjoqGF7m3Uzivn14Kfjz7BhatsD5BOMBnf3pL2pkGMxfHi6pwG8BDz N2vuflK2PLgcg== 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 v5 sched_ext/for-7.3 06/33] sched_ext: Defer scx_sched kobj sysfs add into the enable workfns Date: Thu, 9 Jul 2026 12:50:14 -1000 Message-ID: <20260709225041.1695495-7-tj@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260709225041.1695495-1-tj@kernel.org> References: <20260709225041.1695495-1-tj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org 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 f12691c839ce..5ed790e016b2 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -5735,7 +5735,9 @@ 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(); @@ -6452,36 +6454,15 @@ 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 @@ -6539,6 +6520,36 @@ 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) { @@ -6761,6 +6772,12 @@ 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 6560a0fa3efa..160ff79faedc 100644 --- a/kernel/sched/ext/internal.h +++ b/kernel/sched/ext/internal.h @@ -1690,6 +1690,7 @@ 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 ce76ae141e0a..9855a9a4e709 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); -- 2.55.0