linux-kernel - [PATCH 4/9] sched/cputime: Support other fields on kcpustat

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Date:   Wed,  6 Nov 2019 04:08:02 +0100
From:   Frederic Weisbecker <frederic@...nel.org>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Jacek Anaszewski <jacek.anaszewski@...il.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Pavel Machek <pavel@....cz>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Yauheni Kaliuta <yauheni.kaliuta@...hat.com>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Rik van Riel <riel@...riel.com>
Subject: [PATCH 4/9] sched/cputime: Support other fields on kcpustat_field()

Now that we support nice updates under vtime accounting, we can provide
tickless values for kcpustat readers of user and guest time.

Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
Cc: Yauheni Kaliuta <yauheni.kaliuta@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Rik van Riel <riel@...riel.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Wanpeng Li <wanpengli@...cent.com>
Cc: Ingo Molnar <mingo@...nel.org>
---
 kernel/sched/cputime.c | 40 +++++++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index e09194415c35..bf4b61f71194 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -1042,6 +1042,15 @@ void task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
 	} while (read_seqcount_retry(&vtime->seqcount, seq));
 }
 
+static u64 kcpustat_user_vtime(struct vtime *vtime)
+{
+	if (vtime->state == VTIME_USER)
+		return vtime->utime + vtime_delta(vtime);
+	else if (vtime->state == VTIME_GUEST)
+		return vtime->gtime + vtime_delta(vtime);
+	return 0;
+}
+
 static int kcpustat_field_vtime(u64 *cpustat,
 				struct vtime *vtime,
 				enum cpu_usage_stat usage,
@@ -1076,9 +1085,30 @@ static int kcpustat_field_vtime(u64 *cpustat,
 
 		*val = cpustat[usage];
 
-		if (vtime->state == VTIME_SYS)
-			*val += vtime->stime + vtime_delta(vtime);
-
+		switch (usage) {
+		case CPUTIME_SYSTEM:
+			if (vtime->state == VTIME_SYS)
+				*val += vtime->stime + vtime_delta(vtime);
+			break;
+		case CPUTIME_USER:
+			if (!vtime->nice)
+				*val += kcpustat_user_vtime(vtime);
+			break;
+		case CPUTIME_NICE:
+			if (vtime->nice)
+				*val += kcpustat_user_vtime(vtime);
+			break;
+		case CPUTIME_GUEST:
+			if (vtime->state == VTIME_GUEST && !vtime->nice)
+				*val += vtime->gtime + vtime_delta(vtime);
+			break;
+		case CPUTIME_GUEST_NICE:
+			if (vtime->state == VTIME_GUEST && vtime->nice)
+				*val += vtime->gtime + vtime_delta(vtime);
+			break;
+		default:
+			break;
+		}
 	} while (read_seqcount_retry(&vtime->seqcount, seq));
 
 	return 0;
@@ -1095,10 +1125,6 @@ u64 kcpustat_field(struct kernel_cpustat *kcpustat,
 	if (!vtime_accounting_enabled_cpu(cpu))
 		return cpustat[usage];
 
-	/* Only support sys vtime for now */
-	if (usage != CPUTIME_SYSTEM)
-		return cpustat[usage];
-
 	rq = cpu_rq(cpu);
 
 	for (;;) {
-- 
2.23.0