| Message ID | 20190528103313.1343-8-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | xen: add core scheduling support | expand |
On Tue, 2019-05-28 at 12:32 +0200, Juergen Gross wrote: > In order to make it easy to iterate over sched_unit elements of a > domain build a single linked list and add an iterator for it. > How about a ',' between domain and build? > For completeness add another iterator for_each_sched_unit_vcpu() > which > will iterate over all vcpus if a sched_unit (right now only one). > This "over all vcpus of a sched_unit" ? > will be needed later for larger scheduling granularity (e.g. cores). > > Signed-off-by: Juergen Gross <jgross@suse.com> > One question: > @@ -279,8 +279,16 @@ struct vcpu > struct sched_unit { > struct vcpu *vcpu; > void *priv; /* scheduler private data */ > + struct sched_unit *next_in_list; > }; > > +#define for_each_sched_unit(d, > e) \ > + for ( (e) = (d)->sched_unit_list; (e) != NULL; (e) = (e)- > >next_in_list ) > + > +#define for_each_sched_unit_vcpu(i, > v) \ > + for ( (v) = (i)->vcpu; (v) != NULL && (v)->sched_unit == > (i); \ > + (v) = (v)->next_in_list ) > + > So, here... sorry if it's me not seeing it, but why the (v)->sched_unit == (i) check is necessary? Do we expect to put in the list of vcpus of a particular unit, vcpus that are in another unit? Regards
On 19.07.19 02:01, Dario Faggioli wrote: > On Tue, 2019-05-28 at 12:32 +0200, Juergen Gross wrote: >> In order to make it easy to iterate over sched_unit elements of a >> domain build a single linked list and add an iterator for it. >> > How about a ',' between domain and build? Okay. > >> For completeness add another iterator for_each_sched_unit_vcpu() >> which >> will iterate over all vcpus if a sched_unit (right now only one). >> This > > "over all vcpus of a sched_unit" ? Oh, of course! > >> will be needed later for larger scheduling granularity (e.g. cores). >> >> Signed-off-by: Juergen Gross <jgross@suse.com> >> > One question: > >> @@ -279,8 +279,16 @@ struct vcpu >> struct sched_unit { >> struct vcpu *vcpu; >> void *priv; /* scheduler private data */ >> + struct sched_unit *next_in_list; >> }; >> >> +#define for_each_sched_unit(d, >> e) \ >> + for ( (e) = (d)->sched_unit_list; (e) != NULL; (e) = (e)- >>> next_in_list ) >> + >> +#define for_each_sched_unit_vcpu(i, >> v) \ >> + for ( (v) = (i)->vcpu; (v) != NULL && (v)->sched_unit == >> (i); \ >> + (v) = (v)->next_in_list ) >> + >> > So, here... sorry if it's me not seeing it, but why the > (v)->sched_unit == (i) check is necessary? > > Do we expect to put in the list of vcpus of a particular unit, vcpus > that are in another unit? Yes. I'm making use of the fact that all vcpus in a unit are consecutive as I'm re-using the already existing list of vcpus in a domain: dom->vcpu0->vcpu1->vcpu2->vcpu3 ^ ^ ! ! unit0-+ ! ! unit2---------------+ Juergen
On Fri, 2019-07-19 at 07:07 +0200, Juergen Gross wrote: > On 19.07.19 02:01, Dario Faggioli wrote: > > On Tue, 2019-05-28 at 12:32 +0200, Juergen Gross wrote: > > > > > How about a ',' between domain and build? > > Okay. > > "over all vcpus of a sched_unit" ? > > Oh, of course! > Thanks. > > One question: > > > > > @@ -279,8 +279,16 @@ struct vcpu > > > struct sched_unit { > > > struct vcpu *vcpu; > > > void *priv; /* scheduler private data > > > */ > > > + struct sched_unit *next_in_list; > > > }; > > > > > > +#define for_each_sched_unit(d, > > > e) \ > > > + for ( (e) = (d)->sched_unit_list; (e) != NULL; (e) = (e)- > > > > next_in_list ) > > > + > > > +#define for_each_sched_unit_vcpu(i, > > > v) \ > > > + for ( (v) = (i)->vcpu; (v) != NULL && (v)->sched_unit == > > > (i); \ > > > + (v) = (v)->next_in_list ) > > > + > > > > > So, here... sorry if it's me not seeing it, but why the > > (v)->sched_unit == (i) check is necessary? > > > > Do we expect to put in the list of vcpus of a particular unit, > > vcpus > > that are in another unit? > > Yes. > Ah! > I'm making use of the fact that all vcpus in a unit are consecutive > as I'm re-using the already existing list of vcpus in a domain: > > dom->vcpu0->vcpu1->vcpu2->vcpu3 > ^ ^ > ! ! > unit0-+ ! > ! > unit2---------------+ > Ok, I see. Can you add a short comment, above the for_each_xxx construct, about that? "All vcpus from all sched units are kept in the same. Only iterate over the ones from a particular unit" Or something like this. Regards
diff --git a/xen/common/schedule.c b/xen/common/schedule.c index 86a43f7192..49d25489ef 100644 --- a/xen/common/schedule.c +++ b/xen/common/schedule.c @@ -249,6 +249,52 @@ static void sched_spin_unlock_double(spinlock_t *lock1, spinlock_t *lock2, spin_unlock_irqrestore(lock1, flags); } +static void sched_free_unit(struct sched_unit *unit) +{ + struct sched_unit *prev_unit; + struct domain *d = unit->vcpu->domain; + + if ( d->sched_unit_list == unit ) + d->sched_unit_list = unit->next_in_list; + else + { + for_each_sched_unit ( d, prev_unit ) + { + if ( prev_unit->next_in_list == unit ) + { + prev_unit->next_in_list = unit->next_in_list; + break; + } + } + } + + unit->vcpu->sched_unit = NULL; + xfree(unit); +} + +static struct sched_unit *sched_alloc_unit(struct vcpu *v) +{ + struct sched_unit *unit, **prev_unit; + struct domain *d = v->domain; + + if ( (unit = xzalloc(struct sched_unit)) == NULL ) + return NULL; + + v->sched_unit = unit; + unit->vcpu = v; + + for ( prev_unit = &d->sched_unit_list; *prev_unit; + prev_unit = &(*prev_unit)->next_in_list ) + if ( (*prev_unit)->next_in_list && + (*prev_unit)->next_in_list->vcpu->vcpu_id > v->vcpu_id ) + break; + + unit->next_in_list = *prev_unit; + *prev_unit = unit; + + return unit; +} + int sched_init_vcpu(struct vcpu *v, unsigned int processor) { struct domain *d = v->domain; @@ -256,10 +302,8 @@ int sched_init_vcpu(struct vcpu *v, unsigned int processor) v->processor = processor; - if ( (unit = xzalloc(struct sched_unit)) == NULL ) + if ( (unit = sched_alloc_unit(v)) == NULL ) return 1; - v->sched_unit = unit; - unit->vcpu = v; /* Initialise the per-vcpu timers. */ init_timer(&v->periodic_timer, vcpu_periodic_timer_fn, @@ -272,8 +316,7 @@ int sched_init_vcpu(struct vcpu *v, unsigned int processor) unit->priv = sched_alloc_vdata(dom_scheduler(d), unit, d->sched_priv); if ( unit->priv == NULL ) { - v->sched_unit = NULL; - xfree(unit); + sched_free_unit(unit); return 1; } @@ -416,8 +459,7 @@ void sched_destroy_vcpu(struct vcpu *v) atomic_dec(&per_cpu(schedule_data, v->processor).urgent_count); sched_remove_unit(vcpu_scheduler(v), unit); sched_free_vdata(vcpu_scheduler(v), unit->priv); - xfree(unit); - v->sched_unit = NULL; + sched_free_unit(unit); } int sched_init_domain(struct domain *d, int poolid) diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h index f549ad60d1..4da1ab201d 100644 --- a/xen/include/xen/sched.h +++ b/xen/include/xen/sched.h @@ -279,8 +279,16 @@ struct vcpu struct sched_unit { struct vcpu *vcpu; void *priv; /* scheduler private data */ + struct sched_unit *next_in_list; }; +#define for_each_sched_unit(d, e) \ + for ( (e) = (d)->sched_unit_list; (e) != NULL; (e) = (e)->next_in_list ) + +#define for_each_sched_unit_vcpu(i, v) \ + for ( (v) = (i)->vcpu; (v) != NULL && (v)->sched_unit == (i); \ + (v) = (v)->next_in_list ) + /* Per-domain lock can be recursively acquired in fault handlers. */ #define domain_lock(d) spin_lock_recursive(&(d)->domain_lock) #define domain_unlock(d) spin_unlock_recursive(&(d)->domain_lock) @@ -339,6 +347,7 @@ struct domain /* Scheduling. */ void *sched_priv; /* scheduler-specific data */ + struct sched_unit *sched_unit_list; struct cpupool *cpupool; struct domain *next_in_list;
In order to make it easy to iterate over sched_unit elements of a domain build a single linked list and add an iterator for it. The new list is guarded by the same mechanisms as the vcpu linked list as it is modified only via vcpu_create() or vcpu_destroy(). For completeness add another iterator for_each_sched_unit_vcpu() which will iterate over all vcpus if a sched_unit (right now only one). This will be needed later for larger scheduling granularity (e.g. cores). Signed-off-by: Juergen Gross <jgross@suse.com> --- xen/common/schedule.c | 56 ++++++++++++++++++++++++++++++++++++++++++------- xen/include/xen/sched.h | 9 ++++++++ 2 files changed, 58 insertions(+), 7 deletions(-)