linux-kernel - [PATCH -tip 27/32] sched/debug: Add CGroup node for printing group cookie if SCHED

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Date:   Tue, 17 Nov 2020 18:19:57 -0500
From:   "Joel Fernandes (Google)" <joel@...lfernandes.org>
To:     Nishanth Aravamudan <naravamudan@...italocean.com>,
        Julien Desfossez <jdesfossez@...italocean.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Vineeth Pillai <viremana@...ux.microsoft.com>,
        Aaron Lu <aaron.lwe@...il.com>,
        Aubrey Li <aubrey.intel@...il.com>, tglx@...utronix.de,
        linux-kernel@...r.kernel.org
Cc:     mingo@...nel.org, torvalds@...ux-foundation.org,
        fweisbec@...il.com, keescook@...omium.org, kerrnel@...gle.com,
        Phil Auld <pauld@...hat.com>,
        Valentin Schneider <valentin.schneider@....com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Paolo Bonzini <pbonzini@...hat.com>, joel@...lfernandes.org,
        vineeth@...byteword.org, Chen Yu <yu.c.chen@...el.com>,
        Christian Brauner <christian.brauner@...ntu.com>,
        Agata Gruza <agata.gruza@...el.com>,
        Antonio Gomez Iglesias <antonio.gomez.iglesias@...el.com>,
        graf@...zon.com, konrad.wilk@...cle.com, dfaggioli@...e.com,
        pjt@...gle.com, rostedt@...dmis.org, derkling@...gle.com,
        benbjiang@...cent.com,
        Alexandre Chartre <alexandre.chartre@...cle.com>,
        James.Bottomley@...senpartnership.com, OWeisse@...ch.edu,
        Dhaval Giani <dhaval.giani@...cle.com>,
        Junaid Shahid <junaids@...gle.com>, jsbarnes@...gle.com,
        chris.hyser@...cle.com, Ben Segall <bsegall@...gle.com>,
        Josh Don <joshdon@...gle.com>, Hao Luo <haoluo@...gle.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Aubrey Li <aubrey.li@...ux.intel.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Tim Chen <tim.c.chen@...el.com>
Subject: [PATCH -tip 27/32] sched/debug: Add CGroup node for printing group cookie if SCHED_DEBUG

This will be used by kselftest to verify the CGroup cookie value that is
set by the CGroup interface.

Reviewed-by: Josh Don <joshdon@...gle.com>
Tested-by: Julien Desfossez <jdesfossez@...italocean.com>
Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>
---
 kernel/sched/core.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 8f17ec8e993e..f1d9762b571a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -10277,6 +10277,21 @@ static u64 cpu_core_tag_color_read_u64(struct cgroup_subsys_state *css, struct c
 	return tg->core_tag_color;
 }
 
+#ifdef CONFIG_SCHED_DEBUG
+static u64 cpu_core_group_cookie_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+	unsigned long group_cookie, color;
+
+	cpu_core_get_group_cookie_and_color(css_tg(css), &group_cookie, &color);
+
+	/*
+	 * Combine group_cookie and color into a single 64 bit value, for
+	 * display purposes only.
+	 */
+	return (group_cookie << 32) | (color & 0xffffffff);
+}
+#endif
+
 struct write_core_tag {
 	struct cgroup_subsys_state *css;
 	unsigned long cookie;
@@ -10550,6 +10565,14 @@ static struct cftype cpu_legacy_files[] = {
 		.read_u64 = cpu_core_tag_color_read_u64,
 		.write_u64 = cpu_core_tag_color_write_u64,
 	},
+#ifdef CONFIG_SCHED_DEBUG
+	/* Read the effective cookie (color+tag) of the group. */
+	{
+		.name = "core_group_cookie",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = cpu_core_group_cookie_read_u64,
+	},
+#endif
 #endif
 #ifdef CONFIG_UCLAMP_TASK_GROUP
 	{
@@ -10737,6 +10760,14 @@ static struct cftype cpu_files[] = {
 		.read_u64 = cpu_core_tag_color_read_u64,
 		.write_u64 = cpu_core_tag_color_write_u64,
 	},
+#ifdef CONFIG_SCHED_DEBUG
+	/* Read the effective cookie (color+tag) of the group. */
+	{
+		.name = "core_group_cookie",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = cpu_core_group_cookie_read_u64,
+	},
+#endif
 #endif
 #ifdef CONFIG_CFS_BANDWIDTH
 	{
-- 
2.29.2.299.gdc1121823c-goog