lkml.org 
[lkml]   [2019]   [Oct]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 03/14] sched/cputime: Add vtime guest task state
Date
Record guest as a VTIME state instead of guessing it from VTIME_SYS and
PF_VCPU. This is going to simplify the cputime read side especially as
its state machine is going to further expand in order to fully support
kcpustat on nohz_full.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Ingo Molnar <mingo@kernel.org>
---
include/linux/sched.h | 2 ++
kernel/sched/cputime.c | 18 +++++++++++-------
2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4ae19be2c126..988c4da00c31 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -255,6 +255,8 @@ enum vtime_state {
VTIME_SYS,
/* Task runs in userspace in a CPU with VTIME active: */
VTIME_USER,
+ /* Task runs as guests in a CPU with VTIME active: */
+ VTIME_GUEST,
};

struct vtime {
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 2e885e870aa1..34086afc3518 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -733,7 +733,7 @@ static void __vtime_account_kernel(struct task_struct *tsk,
struct vtime *vtime)
{
/* We might have scheduled out from guest path */
- if (tsk->flags & PF_VCPU)
+ if (vtime->state == VTIME_GUEST)
vtime_account_guest(tsk, vtime);
else
vtime_account_system(tsk, vtime);
@@ -788,6 +788,7 @@ void vtime_guest_enter(struct task_struct *tsk)
write_seqcount_begin(&vtime->seqcount);
vtime_account_system(tsk, vtime);
tsk->flags |= PF_VCPU;
+ vtime->state = VTIME_GUEST;
write_seqcount_end(&vtime->seqcount);
}
EXPORT_SYMBOL_GPL(vtime_guest_enter);
@@ -799,6 +800,7 @@ void vtime_guest_exit(struct task_struct *tsk)
write_seqcount_begin(&vtime->seqcount);
vtime_account_guest(tsk, vtime);
tsk->flags &= ~PF_VCPU;
+ vtime->state = VTIME_SYS;
write_seqcount_end(&vtime->seqcount);
}
EXPORT_SYMBOL_GPL(vtime_guest_exit);
@@ -826,6 +828,8 @@ void vtime_task_switch_generic(struct task_struct *prev)
write_seqcount_begin(&vtime->seqcount);
if (is_idle_task(current))
vtime->state = VTIME_IDLE;
+ else if (current->flags & PF_VCPU)
+ vtime->state = VTIME_GUEST;
else
vtime->state = VTIME_SYS;
vtime->starttime = sched_clock();
@@ -860,7 +864,7 @@ u64 task_gtime(struct task_struct *t)
seq = read_seqcount_begin(&vtime->seqcount);

gtime = t->gtime;
- if (vtime->state == VTIME_SYS && t->flags & PF_VCPU)
+ if (vtime->state == VTIME_GUEST)
gtime += vtime->gtime + vtime_delta(vtime);

} while (read_seqcount_retry(&vtime->seqcount, seq));
@@ -898,13 +902,13 @@ void task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
delta = vtime_delta(vtime);

/*
- * Task runs either in user or kernel space, add pending nohz time to
- * the right place.
+ * Task runs either in user (including guest) or kernel space,
+ * add pending nohz time to the right place.
*/
- if (vtime->state == VTIME_USER || t->flags & PF_VCPU)
- *utime += vtime->utime + delta;
- else if (vtime->state == VTIME_SYS)
+ if (vtime->state == VTIME_SYS)
*stime += vtime->stime + delta;
+ else
+ *utime += vtime->utime + delta;
} while (read_seqcount_retry(&vtime->seqcount, seq));
}
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
--
2.23.0
\
 
 \ /
  Last update: 2019-10-16 04:57    [W:1.008 / U:0.112 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site