From: Rik van Riel <riel@redhat.com>
To: Glauber Costa <glommer@redhat.com>
Cc: kvm@vger.kernel.org, avi@redhat.com, zamsden@redhat.com,
mtosatti@redhat.com
Subject: Re: [RFC 5/7] kvm steal time implementation
Date: Thu, 26 Aug 2010 18:13:07 -0400 [thread overview]
Message-ID: <4C76E6F3.5020402@redhat.com> (raw)
In-Reply-To: <1282772597-4183-6-git-send-email-glommer@redhat.com>
On 08/25/2010 05:43 PM, Glauber Costa wrote:
> This is the proposed kvm-side steal time implementation.
> It is migration safe, as it checks flags at every read.
>
> Signed-off-by: Glauber Costa<glommer@redhat.com>
> ---
> arch/x86/kernel/kvmclock.c | 35 +++++++++++++++++++++++++++++++++++
> 1 files changed, 35 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> index eb9b76c..a1f4852 100644
> --- a/arch/x86/kernel/kvmclock.c
> +++ b/arch/x86/kernel/kvmclock.c
> @@ -18,6 +18,8 @@
>
> #include<linux/clocksource.h>
> #include<linux/kvm_para.h>
> +#include<linux/kernel_stat.h>
> +#include<linux/sched.h>
> #include<asm/pvclock.h>
> #include<asm/msr.h>
> #include<asm/apic.h>
> @@ -41,6 +43,7 @@ early_param("no-kvmclock", parse_no_kvmclock);
>
> /* The hypervisor will put information about time periodically here */
> static DEFINE_PER_CPU_SHARED_ALIGNED(struct pvclock_vcpu_time_info, hv_clock);
> +static DEFINE_PER_CPU(u64, steal_info);
> static struct pvclock_wall_clock wall_clock;
>
> /*
> @@ -82,6 +85,32 @@ static cycle_t kvm_clock_read(void)
> return ret;
> }
>
> +static DEFINE_PER_CPU(u64, steal_info);
> +
> +cputime_t kvm_get_steal_time(void)
> +{
> + u64 delta = 0;
> + u64 *last_steal_info, this_steal_info;
> + struct pvclock_vcpu_time_info *src;
> +
> + src =&get_cpu_var(hv_clock);
> + if (!(src->flags& PVCLOCK_STEAL_BIT))
> + goto out;
> +
> + this_steal_info = src->steal_time;
> + put_cpu_var(hv_clock);
> +
> + last_steal_info =&get_cpu_var(steal_info);
> +
> + delta = this_steal_info - *last_steal_info;
> +
> + *last_steal_info = this_steal_info;
> + put_cpu_var(steal_info);
> +
> +out:
> + return msecs_to_cputime(delta);
> +}
Can this be changed to properly deal with overflow in
src->steal_time, the same way we deal with (eg jiffie)
overflow elsewhere in the kernel?
--
All rights reversed
next prev parent reply other threads:[~2010-08-26 22:13 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-25 21:43 [RFC 0/7] KVM steal time implementation Glauber Costa
2010-08-25 21:43 ` [RFC 1/7] Implement getnsboottime kernel API Glauber Costa
2010-08-25 21:43 ` [RFC 2/7] change headers preparing for steal time Glauber Costa
2010-08-25 21:43 ` [RFC 3/7] measure time out of guest Glauber Costa
2010-08-25 21:43 ` [RFC 4/7] change kernel accounting to include steal time Glauber Costa
2010-08-25 21:43 ` [RFC 5/7] kvm steal time implementation Glauber Costa
2010-08-25 21:43 ` [RFC 6/7] touch softlockup watchdog Glauber Costa
2010-08-25 21:43 ` [RFC 7/7] tell guest about steal time feature Glauber Costa
2010-08-26 22:13 ` Rik van Riel [this message]
2010-08-26 22:35 ` [RFC 5/7] kvm steal time implementation Glauber Costa
2010-08-26 17:23 ` [RFC 4/7] change kernel accounting to include steal time Marcelo Tosatti
2010-08-26 20:28 ` Glauber Costa
2010-08-26 20:47 ` Marcelo Tosatti
2010-08-26 21:05 ` Rik van Riel
2010-08-26 21:13 ` Glauber Costa
2010-08-26 21:14 ` Anthony Liguori
2010-08-26 21:40 ` Glauber Costa
2010-08-26 23:12 ` Marcelo Tosatti
2010-08-27 0:33 ` Glauber Costa
2010-08-27 15:25 ` Marcelo Tosatti
2010-08-26 21:19 ` Rik van Riel
2010-08-26 21:39 ` Glauber Costa
2010-08-29 9:59 ` Avi Kivity
2010-08-29 15:13 ` Rik van Riel
2010-08-29 15:25 ` Avi Kivity
2010-08-29 15:42 ` Rik van Riel
2010-08-29 15:47 ` Avi Kivity
2010-08-30 12:42 ` Glauber Costa
2010-08-30 13:15 ` Avi Kivity
2010-08-26 20:54 ` [RFC 3/7] measure time out of guest Zachary Amsden
2010-08-26 21:14 ` Glauber Costa
2010-08-29 9:53 ` Avi Kivity
2010-08-26 20:44 ` [RFC 2/7] change headers preparing for steal time Zachary Amsden
2010-08-26 21:04 ` Rik van Riel
2010-08-26 21:17 ` Glauber Costa
2010-08-26 22:11 ` Rik van Riel
2010-08-29 9:51 ` Avi Kivity
2010-08-30 12:44 ` Glauber Costa
2010-08-30 13:10 ` Avi Kivity
2010-08-26 19:46 ` [RFC 1/7] Implement getnsboottime kernel API Rik van Riel
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