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From: George Dunlap <george.dunlap@citrix.com>
To: Dario Faggioli <dario.faggioli@citrix.com>,
	xen-devel@lists.xenproject.org
Cc: George Dunlap <george.dunlap@eu.citrix.com>,
	Tianyang Chen <tiche@seas.upenn.edu>,
	Meng Xu <mengxu@cis.upenn.edu>
Subject: Re: [PATCH 01/16] xen: sched: fix locking when allocating an RTDS pCPU
Date: Wed, 23 Mar 2016 15:37:41 +0000	[thread overview]
Message-ID: <56F2B845.6030108@citrix.com> (raw)
In-Reply-To: <20160318190401.8117.69985.stgit@Solace.station>

On 18/03/16 19:04, Dario Faggioli wrote:
> as doing that include changing the scheduler lock
> mapping for the pCPU itself, and the correct way
> of doing that is:
>  - take the lock that the pCPU is using right now
>    (which may be the lock of another scheduler);
>  - change the mapping of the lock to the RTDS one;
>  - release the lock (the one that has actually been
>    taken!)
> 
> Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>

Reviewed-by: George Dunlap <george.dunlap@citrix.com>

> ---
> Cc: Meng Xu <mengxu@cis.upenn.edu>
> Cc: George Dunlap <george.dunlap@eu.citrix.com>
> Cc: Tianyang Chen <tiche@seas.upenn.edu>
> ---
>  xen/common/sched_rt.c |    9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
> index c896a6f..d98bfb6 100644
> --- a/xen/common/sched_rt.c
> +++ b/xen/common/sched_rt.c
> @@ -653,11 +653,16 @@ static void *
>  rt_alloc_pdata(const struct scheduler *ops, int cpu)
>  {
>      struct rt_private *prv = rt_priv(ops);
> +    spinlock_t *old_lock;
>      unsigned long flags;
>  
> -    spin_lock_irqsave(&prv->lock, flags);
> +    /* Move the scheduler lock to our global runqueue lock.  */
> +    old_lock = pcpu_schedule_lock_irqsave(cpu, &flags);
> +
>      per_cpu(schedule_data, cpu).schedule_lock = &prv->lock;
> -    spin_unlock_irqrestore(&prv->lock, flags);
> +
> +    /* _Not_ pcpu_schedule_unlock(): per_cpu().schedule_lock changed! */
> +    spin_unlock_irqrestore(old_lock, flags);
>  
>      if ( !alloc_cpumask_var(&_cpumask_scratch[cpu]) )
>          return NULL;
> 


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  parent reply	other threads:[~2016-03-23 15:37 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-18 19:03 [PATCH 00/16] Fixes and improvement (including hard affinity!) for Credit2 Dario Faggioli
2016-03-18 19:04 ` [PATCH 01/16] xen: sched: fix locking when allocating an RTDS pCPU Dario Faggioli
2016-03-19  2:22   ` Meng Xu
2016-03-23 15:37   ` George Dunlap [this message]
2016-03-18 19:04 ` [PATCH 02/16] xen: sched: add .init_pdata hook to the scheduler interface Dario Faggioli
2016-03-22  8:08   ` Juergen Gross
2016-03-23 17:32   ` George Dunlap
2016-03-18 19:04 ` [PATCH 03/16] xen: sched: make implementing .alloc_pdata optional Dario Faggioli
2016-03-19  2:23   ` Meng Xu
2016-03-21 14:22   ` Jan Beulich
2016-03-23 17:36     ` George Dunlap
2016-03-24  9:43       ` Jan Beulich
2016-03-24 13:14         ` Dario Faggioli
2016-03-21 14:48   ` Juergen Gross
2016-03-21 15:07     ` Jan Beulich
2016-04-01 17:01       ` Dario Faggioli
2016-04-04  4:21         ` Juergen Gross
2016-04-04  6:13         ` Jan Beulich
2016-04-05 16:01           ` Dario Faggioli
2016-03-23 17:38   ` George Dunlap
2016-03-18 19:04 ` [PATCH 04/16] xen: sched: implement .init_pdata in all schedulers Dario Faggioli
2016-03-19  2:24   ` Meng Xu
2016-03-22  8:03   ` Juergen Gross
2016-03-23 17:46     ` George Dunlap
2016-03-18 19:04 ` [PATCH 05/16] xen: sched: move pCPU initialization in an helper Dario Faggioli
2016-03-23 17:51   ` George Dunlap
2016-03-23 18:09     ` George Dunlap
2016-03-24 13:21     ` Dario Faggioli
2016-03-18 19:04 ` [PATCH 06/16] xen: sched: prepare a .switch_sched hook for Credit1 Dario Faggioli
2016-03-18 19:04 ` [PATCH 07/16] xen: sched: prepare a .switch_sched hook for Credit2 Dario Faggioli
2016-03-18 19:04 ` [PATCH 08/16] " Dario Faggioli
2016-03-19  2:24   ` Meng Xu
2016-03-21 14:25   ` Jan Beulich
2016-03-18 19:05 ` [PATCH 09/16] xen: sched: close potential races when switching scheduler to CPUs Dario Faggioli
2016-03-19  2:25   ` Meng Xu
2016-03-23 19:05   ` George Dunlap
2016-04-05 16:26     ` Dario Faggioli
2016-04-06 15:51       ` Dario Faggioli
2016-03-24 12:14   ` George Dunlap
2016-04-05 17:37     ` Dario Faggioli
2016-04-06 16:21       ` Dario Faggioli
2016-03-18 19:05 ` [PATCH 10/16] xen: sched: improve credit2 bootparams' scope, placement and signedness Dario Faggioli
2016-03-21 14:51   ` Juergen Gross
2016-03-24 12:20   ` George Dunlap
2016-03-18 19:05 ` [PATCH 11/16] xen: sched: on Credit2, don't reprogram the timer if idle Dario Faggioli
2016-03-24 15:03   ` George Dunlap
2016-03-18 19:05 ` [PATCH 12/16] xen: sched: fix per-socket runqueue creation in credit2 Dario Faggioli
2016-03-24 12:24   ` George Dunlap
2016-03-18 19:05 ` [PATCH 13/16] xen: sched: allow for choosing credit2 runqueues configuration at boot Dario Faggioli
2016-03-22  7:46   ` Juergen Gross
2016-03-24 12:36   ` George Dunlap
2016-03-18 19:05 ` [PATCH 14/16] xen: sched: per-core runqueues as default in credit2 Dario Faggioli
2016-03-24 12:37   ` George Dunlap
2016-03-18 19:06 ` [PATCH 15/16] xen: sched: scratch space for cpumasks on Credit2 Dario Faggioli
2016-03-18 19:27   ` Andrew Cooper
2016-03-24 12:44     ` George Dunlap
2016-03-24 12:56       ` Andrew Cooper
2016-03-24 13:10       ` Dario Faggioli
2016-03-18 19:06 ` [PATCH 16/16] xen: sched: implement vcpu hard affinity in Credit2 Dario Faggioli
2016-03-24 15:42   ` George Dunlap
2016-04-05 16:50     ` Dario Faggioli

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