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From: Tejun Heo <tj@kernel.org>
To: torvalds@linux-foundation.org, mingo@redhat.com,
	peterz@infradead.org, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, vschneid@redhat.com, ast@kernel.org,
	daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org,
	joshdon@google.com, brho@google.com, pjt@google.com,
	derkling@google.com, haoluo@google.com, dvernet@meta.com,
	dschatzberg@meta.com, dskarlat@cs.cmu.edu, riel@surriel.com,
	changwoo@igalia.com, himadrics@inria.fr, memxor@gmail.com
Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
	kernel-team@meta.com, Tejun Heo <tj@kernel.org>
Subject: [PATCH 01/36] cgroup: Implement cgroup_show_cftypes()
Date: Fri, 10 Nov 2023 16:47:27 -1000	[thread overview]
Message-ID: <20231111024835.2164816-2-tj@kernel.org> (raw)
In-Reply-To: <20231111024835.2164816-1-tj@kernel.org>

Implement cgroup_show_cftypes() which shows and hides all cgroup files
associated with the specified set of cgroup file types. CFTYPE_HIDDEN flag
is added so that files can be created hidden from the get-go.

cgroup_show_cftypes() can be used whether the cftypes are added or not. It
also combines with cgroup_show_file() so that a given file is visible iff
both its cftype and cfile are visible.

This will be used by a new sched_class to selectively show and hide CPU
controller interface files depending on whether they're supported.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: David Vernet <dvernet@meta.com>
Acked-by: Josh Don <joshdon@google.com>
Acked-by: Hao Luo <haoluo@google.com>
Acked-by: Barret Rhoden <brho@google.com>
---
 include/linux/cgroup-defs.h |  8 +++
 include/linux/cgroup.h      |  1 +
 kernel/cgroup/cgroup.c      | 97 ++++++++++++++++++++++++++++++++++---
 3 files changed, 99 insertions(+), 7 deletions(-)

diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 265da00a1a8b..6194d7c13573 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -127,12 +127,18 @@ enum {
 	CFTYPE_WORLD_WRITABLE	= (1 << 4),	/* (DON'T USE FOR NEW FILES) S_IWUGO */
 	CFTYPE_DEBUG		= (1 << 5),	/* create when cgroup_debug */
 
+	CFTYPE_HIDDEN		= (1 << 6),	/* file type hidden, see cgroup_show_cftypes() */
+
 	/* internal flags, do not use outside cgroup core proper */
 	__CFTYPE_ONLY_ON_DFL	= (1 << 16),	/* only on default hierarchy */
 	__CFTYPE_NOT_ON_DFL	= (1 << 17),	/* not on default hierarchy */
 	__CFTYPE_ADDED		= (1 << 18),
 };
 
+enum cfile_flags {
+	CFILE_HIDDEN		= (1 << 0),	/* file instance hidden */
+};
+
 /*
  * cgroup_file is the handle for a file instance created in a cgroup which
  * is used, for example, to generate file changed notifications.  This can
@@ -140,7 +146,9 @@ enum {
  */
 struct cgroup_file {
 	/* do not access any fields from outside cgroup core */
+	struct cftype *cft;
 	struct kernfs_node *kn;
+	unsigned int flags;
 	unsigned long notified_at;
 	struct timer_list notify_timer;
 };
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 0ef0af66080e..d164eaeacfa6 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -113,6 +113,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
 int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
 int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
 int cgroup_rm_cftypes(struct cftype *cfts);
+void cgroup_show_cftype(struct cftype *cft, bool show);
 void cgroup_file_notify(struct cgroup_file *cfile);
 void cgroup_file_show(struct cgroup_file *cfile, bool show);
 
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 484adb375b15..d00fa84edd4c 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -4210,10 +4210,13 @@ static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp,
 		return ret;
 	}
 
+	kernfs_show(kn, !(cft->flags & CFTYPE_HIDDEN));
+
 	if (cft->file_offset) {
 		struct cgroup_file *cfile = (void *)css + cft->file_offset;
 
 		timer_setup(&cfile->notify_timer, cgroup_file_notify_timer, 0);
+		cfile->cft = cft;
 
 		spin_lock_irq(&cgroup_file_kn_lock);
 		cfile->kn = kn;
@@ -4489,6 +4492,24 @@ void cgroup_file_notify(struct cgroup_file *cfile)
 	spin_unlock_irqrestore(&cgroup_file_kn_lock, flags);
 }
 
+static struct kernfs_node *cfile_kn_get(struct cgroup_file *cfile)
+{
+	struct kernfs_node *kn;
+
+	spin_lock_irq(&cgroup_file_kn_lock);
+	kn = cfile->kn;
+	kernfs_get(kn);
+	spin_unlock_irq(&cgroup_file_kn_lock);
+
+	return kn;
+}
+
+static bool cfile_visible(struct cgroup_file *cfile)
+{
+	return !(cfile->cft->flags & CFTYPE_HIDDEN) &&
+		!(cfile->flags & CFILE_HIDDEN);
+}
+
 /**
  * cgroup_file_show - show or hide a hidden cgroup file
  * @cfile: target cgroup_file obtained by setting cftype->file_offset
@@ -4498,15 +4519,20 @@ void cgroup_file_show(struct cgroup_file *cfile, bool show)
 {
 	struct kernfs_node *kn;
 
-	spin_lock_irq(&cgroup_file_kn_lock);
-	kn = cfile->kn;
-	kernfs_get(kn);
-	spin_unlock_irq(&cgroup_file_kn_lock);
+	mutex_lock(&cgroup_mutex);
 
-	if (kn)
-		kernfs_show(kn, show);
+	if (show)
+		cfile->flags &= ~CFILE_HIDDEN;
+	else
+		cfile->flags |= CFILE_HIDDEN;
 
-	kernfs_put(kn);
+	kn = cfile_kn_get(cfile);
+	if (kn) {
+		kernfs_show(kn, cfile_visible(cfile));
+		kernfs_put(kn);
+	}
+
+	mutex_unlock(&cgroup_mutex);
 }
 
 /**
@@ -5534,6 +5560,63 @@ static void offline_css(struct cgroup_subsys_state *css)
 	wake_up_all(&css->cgroup->offline_waitq);
 }
 
+/**
+ * cgroup_show_cftype - show or hide a cgroup file type
+ * @cft: cftype to show or hide
+ * @show: whether to show or hide
+ *
+ * Sets %CFTYPE_HIDDEN and shows/hides the matching files according to @show.
+ * @cft may or may not be added at the time of this call. After hiding, it's
+ * guaranteed that there are no in-flight operations on the hidden files.
+ */
+void cgroup_show_cftype(struct cftype *cft, bool show)
+{
+	struct cgroup_subsys *ss = cft->ss;
+	struct cgroup *root = ss ? &ss->root->cgrp : &cgrp_dfl_root.cgrp;
+	struct cgroup_subsys_state *css;
+
+	mutex_lock(&cgroup_mutex);
+
+	if (show)
+		cft->flags &= ~CFTYPE_HIDDEN;
+	else
+		cft->flags |= CFTYPE_HIDDEN;
+
+	if (!(cft->flags & __CFTYPE_ADDED))
+		goto out_unlock;
+
+	css_for_each_descendant_pre(css, cgroup_css(root, ss)) {
+		struct cgroup *cgrp = css->cgroup;
+		struct kernfs_node *kn;
+
+		if (!(css->flags & CSS_VISIBLE))
+			continue;
+
+		if (cft->file_offset) {
+			struct cgroup_file *cfile =
+				(void *)css + cft->file_offset;
+
+			kn = cfile_kn_get(cfile);
+			if (kn) {
+				kernfs_show(kn, cfile_visible(cfile));
+				kernfs_put(kn);
+			}
+		} else {
+			char buf[CGROUP_FILE_NAME_MAX];
+
+			kn = kernfs_find_and_get(cgrp->kn,
+					cgroup_file_name(cgrp, cft, buf));
+			if (kn) {
+				kernfs_show(kn, show);
+				kernfs_put(kn);
+			}
+		}
+	}
+
+out_unlock:
+	mutex_unlock(&cgroup_mutex);
+}
+
 /**
  * css_create - create a cgroup_subsys_state
  * @cgrp: the cgroup new css will be associated with
-- 
2.42.0


  reply	other threads:[~2023-11-11  2:49 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-11  2:47 [PATCHSET v5] sched: Implement BPF extensible scheduler class Tejun Heo
2023-11-11  2:47 ` Tejun Heo [this message]
2023-11-11  2:47 ` [PATCH 02/36] sched: Restructure sched_class order sanity checks in sched_init() Tejun Heo
2023-11-11  2:47 ` [PATCH 03/36] sched: Allow sched_cgroup_fork() to fail and introduce sched_cancel_fork() Tejun Heo
2023-11-11  2:47 ` [PATCH 04/36] sched: Add sched_class->reweight_task() Tejun Heo
2023-11-11  2:47 ` [PATCH 05/36] sched: Add sched_class->switching_to() and expose check_class_changing/changed() Tejun Heo
2023-11-11  2:47 ` [PATCH 06/36] sched: Factor out cgroup weight conversion functions Tejun Heo
2023-11-11  2:47 ` [PATCH 07/36] sched: Expose css_tg() and __setscheduler_prio() Tejun Heo
2023-11-11  2:47 ` [PATCH 08/36] sched: Enumerate CPU cgroup file types Tejun Heo
2023-11-11  2:47 ` [PATCH 09/36] sched: Add @reason to sched_class->rq_{on|off}line() Tejun Heo
2023-11-11  2:47 ` [PATCH 10/36] sched: Add normal_policy() Tejun Heo
2023-11-11  2:47 ` [PATCH 11/36] sched_ext: Add boilerplate for extensible scheduler class Tejun Heo
2023-11-11  2:47 ` [PATCH 12/36] sched_ext: Implement BPF " Tejun Heo
2023-11-13 13:34   ` Changwoo Min
2023-11-14 19:07     ` Tejun Heo
2023-11-13 20:04   ` Andrea Righi
2023-11-14 19:07     ` Tejun Heo
2023-11-23  8:07   ` Andrea Righi
2023-11-25 19:59     ` Tejun Heo
2023-11-26  9:05       ` Andrea Righi
2023-12-07  2:04   ` [PATCH] scx: set p->scx.ops_state using atomic_long_set_release Changwoo Min
2023-12-08  0:16     ` Tejun Heo
2024-03-23  2:37   ` [PATCH 12/36] sched_ext: Implement BPF extensible scheduler class Joel Fernandes
2024-03-23 22:12     ` Tejun Heo
2024-04-25 21:28       ` Joel Fernandes
2024-04-26 16:57         ` Barret Rhoden
2024-04-26 21:58         ` Tejun Heo
2023-11-11  2:47 ` [PATCH 13/36] sched_ext: Add scx_simple and scx_example_qmap example schedulers Tejun Heo
2023-11-12  4:17   ` kernel test robot
2023-11-12 18:06     ` Tejun Heo
2023-11-11  2:47 ` [PATCH 14/36] sched_ext: Add sysrq-S which disables the BPF scheduler Tejun Heo
2023-11-11  2:47 ` [PATCH 15/36] sched_ext: Implement runnable task stall watchdog Tejun Heo
2023-11-11  2:47 ` [PATCH 16/36] sched_ext: Allow BPF schedulers to disallow specific tasks from joining SCHED_EXT Tejun Heo
2023-11-11  2:47 ` [PATCH 17/36] sched_ext: Allow BPF schedulers to switch all eligible tasks into sched_ext Tejun Heo
2023-11-11  2:47 ` [PATCH 18/36] sched_ext: Print sched_ext info when dumping stack Tejun Heo
2023-11-14 19:23   ` [PATCH v2 " Tejun Heo
2023-11-11  2:47 ` [PATCH 19/36] sched_ext: Implement scx_bpf_kick_cpu() and task preemption support Tejun Heo
2023-11-11  2:47 ` [PATCH 20/36] sched_ext: Add a central scheduler which makes all scheduling decisions on one CPU Tejun Heo
2023-11-11  2:47 ` [PATCH 21/36] sched_ext: Make watchdog handle ops.dispatch() looping stall Tejun Heo
2023-11-11  2:47 ` [PATCH 22/36] sched_ext: Add task state tracking operations Tejun Heo
2023-11-11  2:47 ` [PATCH 23/36] sched_ext: Implement tickless support Tejun Heo
2023-11-11  2:47 ` [PATCH 24/36] sched_ext: Track tasks that are subjects of the in-flight SCX operation Tejun Heo
2023-11-11  2:47 ` [PATCH 25/36] sched_ext: Add cgroup support Tejun Heo
2023-11-11  2:47 ` [PATCH 26/36] sched_ext: Add a cgroup-based core-scheduling scheduler Tejun Heo
2023-11-11  2:47 ` [PATCH 27/36] sched_ext: Add a cgroup scheduler which uses flattened hierarchy Tejun Heo
2023-11-11  2:47 ` [PATCH 28/36] sched_ext: Implement SCX_KICK_WAIT Tejun Heo
2023-11-11  2:47 ` [PATCH 29/36] sched_ext: Implement sched_ext_ops.cpu_acquire/release() Tejun Heo
2023-11-11  2:47 ` [PATCH 30/36] sched_ext: Implement sched_ext_ops.cpu_online/offline() Tejun Heo
2023-11-11  2:47 ` [PATCH 31/36] sched_ext: Implement core-sched support Tejun Heo
2023-11-11  2:47 ` [PATCH 32/36] sched_ext: Add vtime-ordered priority queue to dispatch_q's Tejun Heo
2023-11-11  2:47 ` [PATCH 33/36] sched_ext: Documentation: scheduler: Document extensible scheduler class Tejun Heo
2023-11-11  2:48 ` [PATCH 34/36] sched_ext: Add a basic, userland vruntime scheduler Tejun Heo
2023-11-11  2:48 ` [PATCH 35/36] sched_ext: Add scx_rusty, a rust userspace hybrid scheduler Tejun Heo
2023-11-11  2:48 ` [PATCH 36/36] sched_ext: Add scx_layered, a highly configurable multi-layer scheduler Tejun Heo

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