From: "Jan Beulich" <JBeulich@suse.com>
To: Chong Li <lichong659@gmail.com>
Cc: Chong Li <chong.li@wustl.edu>, Sisu Xi <xisisu@gmail.com>,
George Dunlap <george.dunlap@eu.citrix.com>,
"dario.faggioli" <dario.faggioli@citrix.com>,
xen-devel <xen-devel@lists.xen.org>,
Meng Xu <mengxu@cis.upenn.edu>,
Dagaen Golomb <dgolomb@seas.upenn.edu>
Subject: Re: [PATCH v4 for Xen 4.6 1/4] xen: enable per-VCPU parameter settings for RTDS scheduler
Date: Tue, 11 Aug 2015 03:39:36 -0600 [thread overview]
Message-ID: <55C9DEF8020000780009971A@prv-mh.provo.novell.com> (raw)
In-Reply-To: <CAGHO-ioHmtXHxfHu=T7LF4hPn3p_sYpQLfUHvAZLhwhuB6jwZg@mail.gmail.com>
>>> On 09.08.15 at 17:45, <lichong659@gmail.com> wrote:
> On Mon, Jul 13, 2015 at 3:37 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>> On 11.07.15 at 06:52, <lichong659@gmail.com> wrote:
>>> @@ -1162,8 +1176,82 @@ rt_dom_cntl(
>>> }
>>> spin_unlock_irqrestore(&prv->lock, flags);
>>> break;
>>> + case XEN_DOMCTL_SCHEDOP_getvcpuinfo:
>>> + spin_lock_irqsave(&prv->lock, flags);
>>> + for ( index = 0; index < op->u.v.nr_vcpus; index++ )
>>> + {
>>> + if ( copy_from_guest_offset(&local_sched,
>>> + op->u.v.vcpus, index, 1) )
>>> + {
>>> + rc = -EFAULT;
>>> + break;
>>> + }
>>> + if ( local_sched.vcpuid >= d->max_vcpus ||
>>> + d->vcpu[local_sched.vcpuid] == NULL )
>>> + {
>>> + rc = -EINVAL;
>>> + break;
>>> + }
>>> + svc = rt_vcpu(d->vcpu[local_sched.vcpuid]);
>>> +
>>> + local_sched.s.rtds.budget = svc->budget / MICROSECS(1);
>>> + local_sched.s.rtds.period = svc->period / MICROSECS(1);
>>> +
>>> + if ( __copy_to_guest_offset(op->u.v.vcpus, index,
>>> + &local_sched, 1) )
>>> + {
>>> + rc = -EFAULT;
>>> + break;
>>> + }
>>> + if( hypercall_preempt_check() )
>>> + {
>>> + rc = -ERESTART;
>>> + break;
>>> + }
>>
>> I still don't see how this is supposed to work.
>
> I return -ERESTART here, and the upper layer function (do_domctl) will
> handle this error code by calling hypercall_create_continuation.
I have no idea where you found the upper layer (i.e. the
XEN_DOMCTL_scheduler_op case of do_domctl() to take care of
this).
>>> +} xen_domctl_schedparam_vcpu_t;
>>> +DEFINE_XEN_GUEST_HANDLE(xen_domctl_schedparam_vcpu_t);
>>> +
>>> /* Set or get info? */
>>> #define XEN_DOMCTL_SCHEDOP_putinfo 0
>>> #define XEN_DOMCTL_SCHEDOP_getinfo 1
>>> +#define XEN_DOMCTL_SCHEDOP_putvcpuinfo 2
>>> +#define XEN_DOMCTL_SCHEDOP_getvcpuinfo 3
>>> struct xen_domctl_scheduler_op {
>>> uint32_t sched_id; /* XEN_SCHEDULER_* */
>>> uint32_t cmd; /* XEN_DOMCTL_SCHEDOP_* */
>>> union {
>>> - struct xen_domctl_sched_sedf {
>>> - uint64_aligned_t period;
>>> - uint64_aligned_t slice;
>>> - uint64_aligned_t latency;
>>> - uint32_t extratime;
>>> - uint32_t weight;
>>> - } sedf;
>>> - struct xen_domctl_sched_credit {
>>> - uint16_t weight;
>>> - uint16_t cap;
>>> - } credit;
>>> - struct xen_domctl_sched_credit2 {
>>> - uint16_t weight;
>>> - } credit2;
>>> - struct xen_domctl_sched_rtds {
>>> - uint32_t period;
>>> - uint32_t budget;
>>> - } rtds;
>>> + xen_domctl_sched_sedf_t sedf;
>>> + xen_domctl_sched_credit_t credit;
>>> + xen_domctl_sched_credit2_t credit2;
>>> + xen_domctl_sched_rtds_t rtds;
>>> + struct {
>>> + XEN_GUEST_HANDLE_64(xen_domctl_schedparam_vcpu_t) vcpus;
>>> + uint16_t nr_vcpus;
>>> + } v;
>>
>> And there's still no explicit padding here at all (nor am I convinced
>> that uint16_t is really a good choice for nr_vcpus - uint32_t would
>> seem more natural without causing any problems or structure
>> growth).
>
> I think the size of union u is equal to the size of
> xen_domctl_sched_sedf_t, which is 64*4 bits (if "vcpus" in struct v is
> just a pointer).
Which doesn't in any way address to complaint about missing explicit
padding - I'm not asking you to pad to the size of the union, but to the
size of the unnamed structure you add.
Jan
> The "nr_vcpus" is indeed better to be uint32_t. I'll change it in the
> next version.
>
> Chong
next prev parent reply other threads:[~2015-08-11 9:39 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-11 4:52 [PATCH v4 for Xen 4.6 0/4] Enable per-VCPU parameter settings for RTDS scheduler Chong Li
2015-07-11 4:52 ` [PATCH v4 for Xen 4.6 1/4] xen: enable " Chong Li
2015-07-13 8:37 ` Jan Beulich
2015-08-09 15:45 ` Chong Li
2015-08-11 9:39 ` Jan Beulich [this message]
2015-07-27 15:51 ` Dario Faggioli
2015-08-09 16:08 ` Chong Li
2015-07-11 4:52 ` [PATCH v4 for Xen 4.6 2/4] libxc: " Chong Li
2015-07-27 16:11 ` Dario Faggioli
2015-08-07 16:35 ` Chong Li
2015-07-11 4:52 ` [PATCH v4 for Xen 4.6 3/4] libxl: " Chong Li
2015-07-28 9:15 ` Dario Faggioli
2015-08-07 17:34 ` Chong Li
2015-07-11 4:52 ` [PATCH v4 for Xen 4.6 4/4] xl: " Chong Li
2015-07-28 9:25 ` Dario Faggioli
2015-08-09 14:53 ` Chong Li
2015-07-11 14:33 ` [PATCH v4 for Xen 4.6 0/4] Enable " Wei Liu
2015-07-13 10:27 ` Dario Faggioli
2015-07-14 5:45 ` Meng Xu
2015-07-14 7:13 ` Dario Faggioli
2015-07-27 15:14 ` Dario Faggioli
2015-08-07 15:50 ` Chong Li
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