From: Meng Xu <mengxu@cis.upenn.edu>
To: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Juergen Gross <jgross@suse.com>,
George Dunlap <george.dunlap@eu.citrix.com>,
Robert VanVossen <robert.vanvossen@dornerworks.com>,
Josh Whitehead <josh.whitehead@dornerworks.com>,
Jan Beulich <JBeulich@suse.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 03/16] xen: sched: make implementing .alloc_pdata optional
Date: Fri, 18 Mar 2016 22:23:22 -0400 [thread overview]
Message-ID: <CAENZ-+nO-jRfLS_y4sWsynkM11R9zusxCTBUE5pnYxM8BK7Upw@mail.gmail.com> (raw)
In-Reply-To: <20160318190416.8117.57233.stgit@Solace.station>
On Fri, Mar 18, 2016 at 3:04 PM, Dario Faggioli
<dario.faggioli@citrix.com> wrote:
> The .alloc_pdata scheduler hook must, before this change,
> be implemented by all schedulers --even those ones that
> don't need to allocate anything.
>
> Make it possible to just use the SCHED_OP(), like for
> the other hooks, by using ERR_PTR() and IS_ERR() for
> error reporting. This:
> - makes NULL a variant of success;
> - allows for errors other than ENOMEM to be properly
> communicated (if ever necessary).
>
> This, in turn, means that schedulers not needing to
> allocate any per-pCPU data, can avoid implementing the
> hook. In fact, the artificial implementation of
> .alloc_pdata in the ARINC653 is removed (and, while there,
> nuke .free_pdata too, as it is equally useless).
>
> Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
> ---
> Cc: George Dunlap <george.dunlap@eu.citrix.com>
> Cc: Robert VanVossen <robert.vanvossen@dornerworks.com>
> Cc: Josh Whitehead <josh.whitehead@dornerworks.com>
> Cc: Meng Xu <mengxu@cis.upenn.edu>
> Cc: Jan Beulich <JBeulich@suse.com>
> Cc: Juergen Gross <jgross@suse.com>
> ---
> static void
> diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
> index d98bfb6..ac8019f 100644
> --- a/xen/common/sched_rt.c
> +++ b/xen/common/sched_rt.c
> @@ -665,7 +665,7 @@ rt_alloc_pdata(const struct scheduler *ops, int cpu)
> spin_unlock_irqrestore(old_lock, flags);
>
> if ( !alloc_cpumask_var(&_cpumask_scratch[cpu]) )
> - return NULL;
> + return ERR_PTR(-ENOMEM);
>
> if ( prv->repl_timer == NULL )
> {
> @@ -673,13 +673,12 @@ rt_alloc_pdata(const struct scheduler *ops, int cpu)
> prv->repl_timer = xzalloc(struct timer);
>
> if ( prv->repl_timer == NULL )
> - return NULL;
> + return ERR_PTR(-ENOMEM);
>
> init_timer(prv->repl_timer, repl_timer_handler, (void *)ops, cpu);
> }
>
> - /* 1 indicates alloc. succeed in schedule.c */
> - return (void *)1;
> + return NULL;
> }
>
> static void
> diff --git a/xen/common/schedule.c b/xen/common/schedule.c
> index 0627eb5..1adc0e2 100644
> --- a/xen/common/schedule.c
> +++ b/xen/common/schedule.c
> @@ -1491,9 +1491,9 @@ static int cpu_schedule_up(unsigned int cpu)
> if ( idle_vcpu[cpu] == NULL )
> return -ENOMEM;
>
> - if ( (ops.alloc_pdata != NULL) &&
> - ((sd->sched_priv = ops.alloc_pdata(&ops, cpu)) == NULL) )
> - return -ENOMEM;
> + sd->sched_priv = SCHED_OP(&ops, alloc_pdata, cpu);
> + if ( IS_ERR(sd->sched_priv) )
> + return PTR_ERR(sd->sched_priv);
>
> return 0;
> }
> @@ -1503,8 +1503,7 @@ static void cpu_schedule_down(unsigned int cpu)
> struct schedule_data *sd = &per_cpu(schedule_data, cpu);
> struct scheduler *sched = per_cpu(scheduler, cpu);
>
> - if ( sd->sched_priv != NULL )
> - SCHED_OP(sched, free_pdata, sd->sched_priv, cpu);
> + SCHED_OP(sched, free_pdata, sd->sched_priv, cpu);
> SCHED_OP(sched, free_vdata, idle_vcpu[cpu]->sched_priv);
>
> idle_vcpu[cpu]->sched_priv = NULL;
> @@ -1599,9 +1598,8 @@ void __init scheduler_init(void)
> idle_domain->max_vcpus = nr_cpu_ids;
> if ( alloc_vcpu(idle_domain, 0, 0) == NULL )
> BUG();
> - if ( ops.alloc_pdata &&
> - !(this_cpu(schedule_data).sched_priv = ops.alloc_pdata(&ops, 0)) )
> - BUG();
> + this_cpu(schedule_data).sched_priv = SCHED_OP(&ops, alloc_pdata, 0);
> + BUG_ON(IS_ERR(this_cpu(schedule_data).sched_priv));
> SCHED_OP(&ops, init_pdata, this_cpu(schedule_data).sched_priv, 0);
> }
>
> @@ -1644,8 +1642,8 @@ int schedule_cpu_switch(unsigned int cpu, struct cpupool *c)
>
> idle = idle_vcpu[cpu];
> ppriv = SCHED_OP(new_ops, alloc_pdata, cpu);
> - if ( ppriv == NULL )
> - return -ENOMEM;
> + if ( IS_ERR(ppriv) )
> + return PTR_ERR(ppriv);
> SCHED_OP(new_ops, init_pdata, ppriv, cpu);
> vpriv = SCHED_OP(new_ops, alloc_vdata, idle, idle->domain->sched_priv);
> if ( vpriv == NULL )
> diff --git a/xen/include/xen/sched-if.h b/xen/include/xen/sched-if.h
> index 70c08c6..560cba5 100644
> --- a/xen/include/xen/sched-if.h
> +++ b/xen/include/xen/sched-if.h
> @@ -9,6 +9,7 @@
> #define __XEN_SCHED_IF_H__
>
> #include <xen/percpu.h>
> +#include <xen/err.h>
>
> /* A global pointer to the initial cpupool (POOL0). */
> extern struct cpupool *cpupool0;
>
For the sched_rt.c and schedule.c,
Reviewed-by: Meng Xu <mengxu@cis.upenn.edu>
Thanks,
Meng
--
Meng Xu
PhD Student in Computer and Information Science
University of Pennsylvania
http://www.cis.upenn.edu/~mengxu/
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Xen-devel mailing list
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next prev parent reply other threads:[~2016-03-19 2:23 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
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 [this message]
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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