linux-kernel - [PATCH 4/5] x86/vmware: Enable steal time accounting

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Date:   Fri, 20 Mar 2020 20:34:42 +0000
From:   Alexey Makhalov <amakhalov@...are.com>
To:     <linux-x86_64@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>, Jonathan Corbet <corbet@....net>,
        "Thomas Gleixner" <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "Borislav Petkov" <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        "Mauro Carvalho Chehab" <mchehab+samsung@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Juergen Gross <jgross@...e.com>,
        "Alexey Makhalov" <amakhalov@...are.com>
Subject: [PATCH 4/5] x86/vmware: Enable steal time accounting

Set paravirt_steal_rq_enabled if steal clock present.
paravirt_steal_rq_enabled is used in sched/core.c to
adjust task progress by offsetting stolen time.
Use 'no-steal-acc' off switch (share same name with KVM)
to disable steal time accounting.

Signed-off-by: Alexey Makhalov <amakhalov@...are.com>
Reviewed-by: Thomas Hellstrom <thellstrom@...are.com>
---
 Documentation/admin-guide/kernel-parameters.txt |  2 +-
 arch/x86/kernel/cpu/vmware.c                    | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 87176a90e61a..07fbdccdd77c 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3152,7 +3152,7 @@
 			[X86,PV_OPS] Disable paravirtualized VMware scheduler
 			clock and use the default one.
 
-	no-steal-acc	[X86,KVM,ARM64] Disable paravirtualized steal time
+	no-steal-acc	[X86,PV_OPS,ARM64] Disable paravirtualized steal time
 			accounting. steal time is computed, but won't
 			influence scheduler behaviour
 
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 59459992ad47..0c65d661d88b 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -125,6 +125,7 @@ static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
 static int vmw_sched_clock __initdata = 1;
 static DEFINE_PER_CPU_DECRYPTED(struct vmware_steal_time, steal_time) __aligned(64);
 static bool has_steal_clock;
+static bool steal_acc __initdata = true; /* steal time accounting */
 
 static __init int setup_vmw_sched_clock(char *s)
 {
@@ -133,6 +134,13 @@ static __init int setup_vmw_sched_clock(char *s)
 }
 early_param("no-vmw-sched-clock", setup_vmw_sched_clock);
 
+static __init int parse_no_stealacc(char *arg)
+{
+	steal_acc = false;
+	return 0;
+}
+early_param("no-steal-acc", parse_no_stealacc);
+
 static unsigned long long notrace vmware_sched_clock(void)
 {
 	unsigned long long ns;
@@ -306,8 +314,11 @@ static int vmware_cpu_down_prepare(unsigned int cpu)
 
 static __init int activate_jump_labels(void)
 {
-	if (has_steal_clock)
+	if (has_steal_clock) {
 		static_key_slow_inc(&paravirt_steal_enabled);
+		if (steal_acc)
+			static_key_slow_inc(&paravirt_steal_rq_enabled);
+	}
 
 	return 0;
 }
-- 
2.14.2