Re: [RT] [PATCH] Make scheduler root_domain modular(sched_classspecific)

From: Ankita Garg
Date: Sun Mar 23 2008 - 07:37:57 EST

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Hi Peter,

On Sun, Mar 23, 2008 at 12:27:07PM +0100, Peter Zijlstra wrote:
> On Sun, 2008-03-23 at 14:32 +0530, Ankita Garg wrote:
> > Hi Gregory,
> >
> > On Sat, Mar 22, 2008 at 12:04:04PM -0600, Gregory Haskins wrote:
> > > >>> On Sat, Mar 22, 2008 at 10:29 AM, in message
> > > <20080322142915.GA9478@xxxxxxxxxx>, Ankita Garg <ankita@xxxxxxxxxx> wrote:
> > > > Hello,
> > > >
> > > > Thanks Gregory for clarifying my question on root_domains infrastructure.
> > > > What
> > > > I was effectively mentioning on irc the other day was to make the
> > > > root_domain
> > > > infrastructure modular, ie sched_class specific. Currently, only rt is
> > > > making
> > > > use of this infrasture. Making it modular would enable ease of extension to
> > > > other sched_classes if required. Trivial patch to that effect.
> > > >
> > > > Patch compile and boot tested.
> > >
> > > Hi Ankita,
> > > Very nice, thanks! Couple of minor nits and further cleanup opportunities inline, but otherwise:
> > >
> > > Acked-by: Gregory Haskins <ghaskins@xxxxxxxxxx>
> > >
> > > >
> > The changes you have suggested are consistent with what we do for rt_rq
> > and cfs_rq. Here is the patch with these modifications.
>
> As this patch doesn't touch -rt specific code you should have provided a
> patch against the upstream code in sched-devel/latest.
>

The cpupri bits have not been added to the sched-devel tree yet. This
patch involves linking to the cpupri from the rt_root_domain. Thus the
patch against the latest RT tree. Pl let me know if I understand it
incorrectly.

> patching file kernel/sched.c
> Hunk #1 FAILED at 337.
> Hunk #2 FAILED at 6337.
> 2 out of 2 hunks FAILED -- rejects in file kernel/sched.c
> patching file kernel/sched_rt.c
> Hunk #3 FAILED at 78.
> Hunk #4 FAILED at 114.
> Hunk #5 FAILED at 363.
> Hunk #6 succeeded at 1005 (offset 406 lines).
> Hunk #7 FAILED at 1169.
> Hunk #8 FAILED at 1178.
> 5 out of 8 hunks FAILED -- rejects in file kernel/sched_rt.c
>
>
> > Signed-off-by: Ankita Garg <ankita@xxxxxxxxxx>
> >
> > Index: linux-2.6.24.3-rt3/kernel/sched.c
> > ===================================================================
> > --- linux-2.6.24.3-rt3.orig/kernel/sched.c 2008-03-21 22:57:04.000000000 +0530
> > +++ linux-2.6.24.3-rt3/kernel/sched.c 2008-03-23 14:09:22.000000000 +0530
> > @@ -337,22 +337,27 @@
> > * object.
> > *
> > */
> > -struct root_domain {
> > - atomic_t refcount;
> > - cpumask_t span;
> > - cpumask_t online;
> >
> > +struct rt_root_domain {
> > /*
> > * The "RT overload" flag: it gets set if a CPU has more than
> > * one runnable RT task.
> > */
> > - cpumask_t rto_mask;
> > - atomic_t rto_count;
> > + cpumask_t overload_mask;
> > + atomic_t overload_count;
> > #ifdef CONFIG_SMP
> > struct cpupri cpupri;
> > #endif
> > };
> >
> > +struct root_domain {
> > + atomic_t refcount;
> > + cpumask_t span;
> > + cpumask_t online;
> > +
> > + struct rt_root_domain rt;
> > +};
> > +
> > /*
> > * By default the system creates a single root-domain with all cpus as
> > * members (mimicking the global state we have today).
> > @@ -6332,7 +6337,7 @@
> > cpus_clear(rd->span);
> > cpus_clear(rd->online);
> >
> > - cpupri_init(&rd->cpupri);
> > + cpupri_init(&rd->rt.cpupri);
> >
> > }
> >
> > Index: linux-2.6.24.3-rt3/kernel/sched_rt.c
> > ===================================================================
> > --- linux-2.6.24.3-rt3.orig/kernel/sched_rt.c 2008-03-21 22:57:04.000000000 +0530
> > +++ linux-2.6.24.3-rt3/kernel/sched_rt.c 2008-03-23 14:12:45.000000000 +0530
> > @@ -7,12 +7,12 @@
> >
> > static inline int rt_overloaded(struct rq *rq)
> > {
> > - return atomic_read(&rq->rd->rto_count);
> > + return atomic_read(&rq->rd->rt.overload_count);
> > }
> >
> > static inline void rt_set_overload(struct rq *rq)
> > {
> > - cpu_set(rq->cpu, rq->rd->rto_mask);
> > + cpu_set(rq->cpu, rq->rd->rt.overload_mask);
> > /*
> > * Make sure the mask is visible before we set
> > * the overload count. That is checked to determine
> > @@ -21,14 +21,14 @@
> > * updated yet.
> > */
> > wmb();
> > - atomic_inc(&rq->rd->rto_count);
> > + atomic_inc(&rq->rd->rt.overload_count);
> > }
> >
> > static inline void rt_clear_overload(struct rq *rq)
> > {
> > /* the order here really doesn't matter */
> > - atomic_dec(&rq->rd->rto_count);
> > - cpu_clear(rq->cpu, rq->rd->rto_mask);
> > + atomic_dec(&rq->rd->rt.overload_count);
> > + cpu_clear(rq->cpu, rq->rd->rt.overload_mask);
> > }
> >
> > static void update_rt_migration(struct rq *rq)
> > @@ -78,7 +78,7 @@
> > #ifdef CONFIG_SMP
> > if (p->prio < rq->rt.highest_prio) {
> > rq->rt.highest_prio = p->prio;
> > - cpupri_set(&rq->rd->cpupri, rq->cpu, p->prio);
> > + cpupri_set(&rq->rd->rt.cpupri, rq->cpu, p->prio);
> > }
> > if (p->nr_cpus_allowed > 1)
> > rq->rt.rt_nr_migratory++;
> > @@ -114,7 +114,7 @@
> > }
> >
> > if (rq->rt.highest_prio != highest_prio)
> > - cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio);
> > + cpupri_set(&rq->rd->rt.cpupri, rq->cpu, rq->rt.highest_prio);
> >
> > update_rt_migration(rq);
> > #endif /* CONFIG_SMP */
> > @@ -363,7 +363,7 @@
> > {
> > int count;
> >
> > - count = cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask);
> > + count = cpupri_find(&task_rq(task)->rd->rt.cpupri, task, lowest_mask);
> >
> > /*
> > * cpupri cannot efficiently tell us how many bits are set, so it only
> > @@ -599,7 +599,7 @@
> >
> > next = pick_next_task_rt(this_rq);
> >
> > - for_each_cpu_mask(cpu, this_rq->rd->rto_mask) {
> > + for_each_cpu_mask(cpu, this_rq->rd->rt.overload_mask) {
> > if (this_cpu == cpu)
> > continue;
> >
> > @@ -763,7 +763,7 @@
> > if (rq->rt.overloaded)
> > rt_set_overload(rq);
> >
> > - cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio);
> > + cpupri_set(&rq->rd->rt.cpupri, rq->cpu, rq->rt.highest_prio);
> > }
> >
> > /* Assumes rq->lock is held */
> > @@ -772,7 +772,7 @@
> > if (rq->rt.overloaded)
> > rt_clear_overload(rq);
> >
> > - cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
> > + cpupri_set(&rq->rd->rt.cpupri, rq->cpu, CPUPRI_INVALID);
> > }
> >
> > /*
> >

--
Regards,
Ankita Garg (ankita@xxxxxxxxxx)
Linux Technology Center
IBM India Systems & Technology Labs,
Bangalore, India
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Next message: Cyrill Gorcunov: "Re: [PATCH] CDROM: use kmalloced buffers instead of buffers onstack"
Previous message: KOSAKI Motohiro: "Re: [PATCH] [2/18] Add basic support for more than one hstate in hugetlbfs"
In reply to: Peter Zijlstra: "Re: [RT] [PATCH] Make scheduler root_domain modular(sched_classspecific)"
Next in thread: Peter Zijlstra: "Re: [RT] [PATCH] Make scheduler root_domain modular(sched_classspecific)"
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