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Subject[tip: x86/vmware] x86/vmware: Enable steal time accounting
The following commit has been merged into the x86/vmware branch of tip:

Commit-ID: e73a8f38f82dd1c41b70a06556bea7dc250cc384
Gitweb: https://git.kernel.org/tip/e73a8f38f82dd1c41b70a06556bea7dc250cc384
Author: Alexey Makhalov <amakhalov@vmware.com>
AuthorDate: Mon, 23 Mar 2020 19:57:06
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 24 Mar 2020 10:06:27 +01:00

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@vmware.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200323195707.31242-5-amakhalov@vmware.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 c07815d..863b37d 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3174,7 +3174,7 @@
[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 cc60461..e885f73 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, vmw_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;
}
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