From: Michael Wolf <mjw@linux.vnet.ibm.com>
To: Rik van Riel <riel@redhat.com>
Cc: linux-kernel@vger.kernel.org, gleb@redhat.com,
kvm@vger.kernel.org, peterz@infradead.org, mtosatti@redhat.com,
glommer@parallels.com, mingo@redhat.com, anthony@codemonkey.ws
Subject: Re: [PATCH 2/4] Expand the steal time msr to also contain the consigned time.
Date: Thu, 07 Feb 2013 08:25:39 -0600 [thread overview]
Message-ID: <5113B963.2080100@linux.vnet.ibm.com> (raw)
In-Reply-To: <5112C7CC.6040803@redhat.com>
On 02/06/2013 03:14 PM, Rik van Riel wrote:
> On 02/05/2013 04:49 PM, Michael Wolf wrote:
>> Expand the steal time msr to also contain the consigned time.
>>
>> Signed-off-by: Michael Wolf <mjw@linux.vnet.ibm.com>
>> ---
>> arch/x86/include/asm/paravirt.h | 4 ++--
>> arch/x86/include/asm/paravirt_types.h | 2 +-
>> arch/x86/kernel/kvm.c | 7 ++-----
>> kernel/sched/core.c | 10 +++++++++-
>> kernel/sched/cputime.c | 2 +-
>> 5 files changed, 15 insertions(+), 10 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/paravirt.h
>> b/arch/x86/include/asm/paravirt.h
>> index 5edd174..9b753ea 100644
>> --- a/arch/x86/include/asm/paravirt.h
>> +++ b/arch/x86/include/asm/paravirt.h
>> @@ -196,9 +196,9 @@ struct static_key;
>> extern struct static_key paravirt_steal_enabled;
>> extern struct static_key paravirt_steal_rq_enabled;
>>
>> -static inline u64 paravirt_steal_clock(int cpu)
>> +static inline void paravirt_steal_clock(int cpu, u64 *steal)
>> {
>> - return PVOP_CALL1(u64, pv_time_ops.steal_clock, cpu);
>> + PVOP_VCALL2(pv_time_ops.steal_clock, cpu, steal);
>> }
>
> This may be a stupid question, but what happens if a KVM
> guest with this change, runs on a kernel that still has
> the old steal time interface?
>
> What happens if the host has the new steal time interface,
> but the guest uses the old interface?
>
> Will both cases continue to work as expected with your
> patch series?
>
> If so, could you document (in the source code) why things
> continue to work?
>
I will test the scenarios you suggest and will report back the results.
next prev parent reply other threads:[~2013-02-07 14:25 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-05 21:49 [PATCH 0/4] Alter steal-time reporting in the guest Michael Wolf
2013-02-05 21:49 ` [PATCH 1/4] Alter the amount of steal time reported by " Michael Wolf
2013-02-05 21:49 ` [PATCH 2/4] Expand the steal time msr to also contain the consigned time Michael Wolf
2013-02-06 21:14 ` Rik van Riel
2013-02-07 14:25 ` Michael Wolf [this message]
2013-02-05 21:49 ` [PATCH 3/4] Add the code to send the consigned time from the host to the guest Michael Wolf
2013-02-06 21:18 ` Rik van Riel
2013-02-07 14:26 ` Michael Wolf
2013-02-05 21:49 ` [PATCH 4/4] Add a timer to allow the separation of consigned from steal time Michael Wolf
2013-02-06 14:36 ` Glauber Costa
2013-02-06 18:07 ` Michael Wolf
2013-02-07 8:46 ` Glauber Costa
2013-02-07 14:27 ` Michael Wolf
2013-02-18 23:57 ` Marcelo Tosatti
2013-03-05 20:17 ` Michael Wolf
2013-03-06 1:35 ` Marcelo Tosatti
2013-02-18 16:43 ` [PATCH 0/4] Alter steal-time reporting in the guest Frederic Weisbecker
2013-02-19 1:11 ` Marcelo Tosatti
2013-03-05 20:22 ` Michael Wolf
2013-03-06 1:41 ` Marcelo Tosatti
2013-03-06 8:13 ` Glauber Costa
2013-03-06 16:29 ` Michael Wolf
2013-03-07 0:52 ` Marcelo Tosatti
2013-03-07 3:11 ` Paul Mackerras
2013-03-07 20:23 ` Michael Wolf
2013-03-06 16:27 ` Michael Wolf
2013-03-07 2:30 ` Marcelo Tosatti
2013-03-07 21:09 ` Michael Wolf
2013-03-07 21:15 ` Michael Wolf
2013-03-07 21:25 ` Marcelo Tosatti
2013-03-07 22:34 ` Michael Wolf
2013-03-08 1:54 ` Marcelo Tosatti
2013-03-08 2:21 ` Marcelo Tosatti
2013-03-06 13:34 ` Frederic Weisbecker
2013-03-06 16:23 ` Michael Wolf
2013-03-06 13:20 ` Frederic Weisbecker
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