| Message ID | 20160318190424.8117.85820.stgit@Solace.station (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Mar 18, 2016 at 3:04 PM, Dario Faggioli <dario.faggioli@citrix.com> wrote: > by borrowing some of the code of .alloc_pdata, i.e., > the bits that perform initializations, leaving only > actual allocations in there, when any, which is the > case for Credit1 and RTDS. I didn't follow the commit log. I think the reason why we "have to" implement .init_pdata in all schedulers is missing in the commit log. > diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c > index ac8019f..b6ac3ad 100644 > --- a/xen/common/sched_rt.c > +++ b/xen/common/sched_rt.c > @@ -649,8 +649,8 @@ rt_deinit(struct scheduler *ops) > * Point per_cpu spinlock to the global system lock; > * All cpu have same global system lock > */ > -static void * > -rt_alloc_pdata(const struct scheduler *ops, int cpu) > +static void > +rt_init_pdata(const struct scheduler *ops, void *pdata, int cpu) > { > struct rt_private *prv = rt_priv(ops); > spinlock_t *old_lock; > @@ -663,7 +663,11 @@ rt_alloc_pdata(const struct scheduler *ops, int cpu) > > /* _Not_ pcpu_schedule_unlock(): per_cpu().schedule_lock changed! */ > spin_unlock_irqrestore(old_lock, flags); > +} > > +static void * > +rt_alloc_pdata(const struct scheduler *ops, int cpu) > +{ > if ( !alloc_cpumask_var(&_cpumask_scratch[cpu]) ) > return ERR_PTR(-ENOMEM); > > @@ -1395,6 +1399,7 @@ static const struct scheduler sched_rtds_def = { > .deinit = rt_deinit, > .alloc_pdata = rt_alloc_pdata, > .free_pdata = rt_free_pdata, > + .init_pdata = rt_init_pdata, > .alloc_domdata = rt_alloc_domdata, > .free_domdata = rt_free_domdata, > .init_domain = rt_dom_init, > Reviewed-by: Meng Xu <mengxu@cis.upenn.edu> Thanks, Meng
On 18/03/16 20:04, Dario Faggioli wrote: > by borrowing some of the code of .alloc_pdata, i.e., > the bits that perform initializations, leaving only > actual allocations in there, when any, which is the > case for Credit1 and RTDS. > > On the other hand, in Credit2, since we don't really > need any per-pCPU data allocation, everything that was > being done in .alloc_pdata, is now done in .init_pdata. > And the fact that now .alloc_pdata can be left undefined, > allows us to just get rid of it. > > Still for Credit2, the fact that .init_pdata is called > during CPU_STARTING (rather than CPU_UP_PREPARE) kills > the need for the scheduler to setup a similar callback > itself, simplifying the code. > > And thanks to such simplification, it is now also ok to > move some of the logic meant at double checking that a > cpu was (or was not) initialized, into ASSERTS (rather > than an if() and a BUG_ON). > > Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com> > --- > Cc: George Dunlap <george.dunlap@eu.citrix.com> > Cc: Meng Xu <mengxu@cis.upenn.edu> > Cc: Juergen Gross <jgross@suse.com> > --- > xen/common/sched_credit.c | 20 +++++++++--- > xen/common/sched_credit2.c | 72 +++----------------------------------------- > xen/common/sched_rt.c | 9 ++++-- > 3 files changed, 26 insertions(+), 75 deletions(-) > > diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c > index 288749f..d4a0f5e 100644 > --- a/xen/common/sched_credit.c > +++ b/xen/common/sched_credit.c > @@ -526,8 +526,6 @@ static void * > csched_alloc_pdata(const struct scheduler *ops, int cpu) > { > struct csched_pcpu *spc; > - struct csched_private *prv = CSCHED_PRIV(ops); > - unsigned long flags; > > /* Allocate per-PCPU info */ > spc = xzalloc(struct csched_pcpu); > @@ -540,6 +538,19 @@ csched_alloc_pdata(const struct scheduler *ops, int cpu) > return ERR_PTR(-ENOMEM); > } > > + return spc; > +} > + > +static void > +csched_init_pdata(const struct scheduler *ops, void *pdata, int cpu) > +{ > + struct csched_private *prv = CSCHED_PRIV(ops); > + struct csched_pcpu * const spc = pdata; > + unsigned long flags; > + > + /* cpu data needs to be allocated, but STILL uninitialized */ > + ASSERT(spc && spc->runq.next == spc->runq.prev && spc->runq.next == NULL); This looks weird. I'd prefer: ASSERT(spc && spc->runq.next == NULL && spc->runq.prev == NULL); > + > spin_lock_irqsave(&prv->lock, flags); > > /* Initialize/update system-wide config */ > @@ -560,16 +571,12 @@ csched_alloc_pdata(const struct scheduler *ops, int cpu) > INIT_LIST_HEAD(&spc->runq); > spc->runq_sort_last = prv->runq_sort; > spc->idle_bias = nr_cpu_ids - 1; > - if ( per_cpu(schedule_data, cpu).sched_priv == NULL ) > - per_cpu(schedule_data, cpu).sched_priv = spc; > > /* Start off idling... */ > BUG_ON(!is_idle_vcpu(curr_on_cpu(cpu))); > cpumask_set_cpu(cpu, prv->idlers); > > spin_unlock_irqrestore(&prv->lock, flags); > - > - return spc; > } > > #ifndef NDEBUG > @@ -2051,6 +2058,7 @@ static const struct scheduler sched_credit_def = { > .alloc_vdata = csched_alloc_vdata, > .free_vdata = csched_free_vdata, > .alloc_pdata = csched_alloc_pdata, > + .init_pdata = csched_init_pdata, > .free_pdata = csched_free_pdata, > .alloc_domdata = csched_alloc_domdata, > .free_domdata = csched_free_domdata, > diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c > index 36dc9ee..b1642a8 100644 > --- a/xen/common/sched_credit2.c > +++ b/xen/common/sched_credit2.c > @@ -1968,7 +1968,8 @@ static void deactivate_runqueue(struct csched2_private *prv, int rqi) > cpumask_clear_cpu(rqi, &prv->active_queues); > } > > -static void init_pcpu(const struct scheduler *ops, int cpu) > +static void > +csched2_init_pdata(const struct scheduler *ops, void *pdata, int cpu) > { > unsigned rqi; > unsigned long flags; > @@ -1978,12 +1979,7 @@ static void init_pcpu(const struct scheduler *ops, int cpu) > > spin_lock_irqsave(&prv->lock, flags); > > - if ( cpumask_test_cpu(cpu, &prv->initialized) ) > - { > - printk("%s: Strange, cpu %d already initialized!\n", __func__, cpu); > - spin_unlock_irqrestore(&prv->lock, flags); > - return; > - } > + ASSERT(!cpumask_test_cpu(cpu, &prv->initialized)); > > /* Figure out which runqueue to put it in */ > rqi = 0; > @@ -2033,20 +2029,6 @@ static void init_pcpu(const struct scheduler *ops, int cpu) > return; > } > > -static void * > -csched2_alloc_pdata(const struct scheduler *ops, int cpu) > -{ > - /* Check to see if the cpu is online yet */ > - /* Note: cpu 0 doesn't get a STARTING callback */ Sorry if I missed it in an other patch: Where is the init_pdata hook being called for cpu 0? Juergen
On 22/03/16 08:03, Juergen Gross wrote: > On 18/03/16 20:04, Dario Faggioli wrote: >> by borrowing some of the code of .alloc_pdata, i.e., >> the bits that perform initializations, leaving only >> actual allocations in there, when any, which is the >> case for Credit1 and RTDS. >> >> On the other hand, in Credit2, since we don't really >> need any per-pCPU data allocation, everything that was >> being done in .alloc_pdata, is now done in .init_pdata. >> And the fact that now .alloc_pdata can be left undefined, >> allows us to just get rid of it. >> >> Still for Credit2, the fact that .init_pdata is called >> during CPU_STARTING (rather than CPU_UP_PREPARE) kills >> the need for the scheduler to setup a similar callback >> itself, simplifying the code. >> >> And thanks to such simplification, it is now also ok to >> move some of the logic meant at double checking that a >> cpu was (or was not) initialized, into ASSERTS (rather >> than an if() and a BUG_ON). >> >> Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com> >> --- >> Cc: George Dunlap <george.dunlap@eu.citrix.com> >> Cc: Meng Xu <mengxu@cis.upenn.edu> >> Cc: Juergen Gross <jgross@suse.com> >> --- >> xen/common/sched_credit.c | 20 +++++++++--- >> xen/common/sched_credit2.c | 72 +++----------------------------------------- >> xen/common/sched_rt.c | 9 ++++-- >> 3 files changed, 26 insertions(+), 75 deletions(-) >> >> diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c >> index 288749f..d4a0f5e 100644 >> --- a/xen/common/sched_credit.c >> +++ b/xen/common/sched_credit.c >> @@ -526,8 +526,6 @@ static void * >> csched_alloc_pdata(const struct scheduler *ops, int cpu) >> { >> struct csched_pcpu *spc; >> - struct csched_private *prv = CSCHED_PRIV(ops); >> - unsigned long flags; >> >> /* Allocate per-PCPU info */ >> spc = xzalloc(struct csched_pcpu); >> @@ -540,6 +538,19 @@ csched_alloc_pdata(const struct scheduler *ops, int cpu) >> return ERR_PTR(-ENOMEM); >> } >> >> + return spc; >> +} >> + >> +static void >> +csched_init_pdata(const struct scheduler *ops, void *pdata, int cpu) >> +{ >> + struct csched_private *prv = CSCHED_PRIV(ops); >> + struct csched_pcpu * const spc = pdata; >> + unsigned long flags; >> + >> + /* cpu data needs to be allocated, but STILL uninitialized */ >> + ASSERT(spc && spc->runq.next == spc->runq.prev && spc->runq.next == NULL); > > This looks weird. I'd prefer: > > ASSERT(spc && spc->runq.next == NULL && spc->runq.prev == NULL); I prefer Juergen's suggestion too. I wouldn't say it's worth respinning over, but since you have to make adjustments to the previous patch anyway, you might as well change this while you're at it. With that change: Reviewed-by: George Dunlap <george.dunlap@citrix.com>
diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c index 288749f..d4a0f5e 100644 --- a/xen/common/sched_credit.c +++ b/xen/common/sched_credit.c @@ -526,8 +526,6 @@ static void * csched_alloc_pdata(const struct scheduler *ops, int cpu) { struct csched_pcpu *spc; - struct csched_private *prv = CSCHED_PRIV(ops); - unsigned long flags; /* Allocate per-PCPU info */ spc = xzalloc(struct csched_pcpu); @@ -540,6 +538,19 @@ csched_alloc_pdata(const struct scheduler *ops, int cpu) return ERR_PTR(-ENOMEM); } + return spc; +} + +static void +csched_init_pdata(const struct scheduler *ops, void *pdata, int cpu) +{ + struct csched_private *prv = CSCHED_PRIV(ops); + struct csched_pcpu * const spc = pdata; + unsigned long flags; + + /* cpu data needs to be allocated, but STILL uninitialized */ + ASSERT(spc && spc->runq.next == spc->runq.prev && spc->runq.next == NULL); + spin_lock_irqsave(&prv->lock, flags); /* Initialize/update system-wide config */ @@ -560,16 +571,12 @@ csched_alloc_pdata(const struct scheduler *ops, int cpu) INIT_LIST_HEAD(&spc->runq); spc->runq_sort_last = prv->runq_sort; spc->idle_bias = nr_cpu_ids - 1; - if ( per_cpu(schedule_data, cpu).sched_priv == NULL ) - per_cpu(schedule_data, cpu).sched_priv = spc; /* Start off idling... */ BUG_ON(!is_idle_vcpu(curr_on_cpu(cpu))); cpumask_set_cpu(cpu, prv->idlers); spin_unlock_irqrestore(&prv->lock, flags); - - return spc; } #ifndef NDEBUG @@ -2051,6 +2058,7 @@ static const struct scheduler sched_credit_def = { .alloc_vdata = csched_alloc_vdata, .free_vdata = csched_free_vdata, .alloc_pdata = csched_alloc_pdata, + .init_pdata = csched_init_pdata, .free_pdata = csched_free_pdata, .alloc_domdata = csched_alloc_domdata, .free_domdata = csched_free_domdata, diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c index 36dc9ee..b1642a8 100644 --- a/xen/common/sched_credit2.c +++ b/xen/common/sched_credit2.c @@ -1968,7 +1968,8 @@ static void deactivate_runqueue(struct csched2_private *prv, int rqi) cpumask_clear_cpu(rqi, &prv->active_queues); } -static void init_pcpu(const struct scheduler *ops, int cpu) +static void +csched2_init_pdata(const struct scheduler *ops, void *pdata, int cpu) { unsigned rqi; unsigned long flags; @@ -1978,12 +1979,7 @@ static void init_pcpu(const struct scheduler *ops, int cpu) spin_lock_irqsave(&prv->lock, flags); - if ( cpumask_test_cpu(cpu, &prv->initialized) ) - { - printk("%s: Strange, cpu %d already initialized!\n", __func__, cpu); - spin_unlock_irqrestore(&prv->lock, flags); - return; - } + ASSERT(!cpumask_test_cpu(cpu, &prv->initialized)); /* Figure out which runqueue to put it in */ rqi = 0; @@ -2033,20 +2029,6 @@ static void init_pcpu(const struct scheduler *ops, int cpu) return; } -static void * -csched2_alloc_pdata(const struct scheduler *ops, int cpu) -{ - /* Check to see if the cpu is online yet */ - /* Note: cpu 0 doesn't get a STARTING callback */ - if ( cpu == 0 || cpu_to_socket(cpu) != XEN_INVALID_SOCKET_ID ) - init_pcpu(ops, cpu); - else - printk("%s: cpu %d not online yet, deferring initializatgion\n", - __func__, cpu); - - return NULL; -} - static void csched2_free_pdata(const struct scheduler *ops, void *pcpu, int cpu) { @@ -2058,7 +2040,7 @@ csched2_free_pdata(const struct scheduler *ops, void *pcpu, int cpu) spin_lock_irqsave(&prv->lock, flags); - BUG_ON(!cpumask_test_cpu(cpu, &prv->initialized)); + ASSERT(cpumask_test_cpu(cpu, &prv->initialized)); /* Find the old runqueue and remove this cpu from it */ rqi = prv->runq_map[cpu]; @@ -2096,49 +2078,6 @@ csched2_free_pdata(const struct scheduler *ops, void *pcpu, int cpu) } static int -csched2_cpu_starting(int cpu) -{ - struct scheduler *ops; - - /* Hope this is safe from cpupools switching things around. :-) */ - ops = per_cpu(scheduler, cpu); - - if ( ops->alloc_pdata == csched2_alloc_pdata ) - init_pcpu(ops, cpu); - - return NOTIFY_DONE; -} - -static int cpu_credit2_callback( - struct notifier_block *nfb, unsigned long action, void *hcpu) -{ - unsigned int cpu = (unsigned long)hcpu; - int rc = 0; - - switch ( action ) - { - case CPU_STARTING: - csched2_cpu_starting(cpu); - break; - default: - break; - } - - return !rc ? NOTIFY_DONE : notifier_from_errno(rc); -} - -static struct notifier_block cpu_credit2_nfb = { - .notifier_call = cpu_credit2_callback -}; - -static int -csched2_global_init(void) -{ - register_cpu_notifier(&cpu_credit2_nfb); - return 0; -} - -static int csched2_init(struct scheduler *ops) { int i; @@ -2216,12 +2155,11 @@ static const struct scheduler sched_credit2_def = { .dump_cpu_state = csched2_dump_pcpu, .dump_settings = csched2_dump, - .global_init = csched2_global_init, .init = csched2_init, .deinit = csched2_deinit, .alloc_vdata = csched2_alloc_vdata, .free_vdata = csched2_free_vdata, - .alloc_pdata = csched2_alloc_pdata, + .init_pdata = csched2_init_pdata, .free_pdata = csched2_free_pdata, .alloc_domdata = csched2_alloc_domdata, .free_domdata = csched2_free_domdata, diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c index ac8019f..b6ac3ad 100644 --- a/xen/common/sched_rt.c +++ b/xen/common/sched_rt.c @@ -649,8 +649,8 @@ rt_deinit(struct scheduler *ops) * Point per_cpu spinlock to the global system lock; * All cpu have same global system lock */ -static void * -rt_alloc_pdata(const struct scheduler *ops, int cpu) +static void +rt_init_pdata(const struct scheduler *ops, void *pdata, int cpu) { struct rt_private *prv = rt_priv(ops); spinlock_t *old_lock; @@ -663,7 +663,11 @@ rt_alloc_pdata(const struct scheduler *ops, int cpu) /* _Not_ pcpu_schedule_unlock(): per_cpu().schedule_lock changed! */ spin_unlock_irqrestore(old_lock, flags); +} +static void * +rt_alloc_pdata(const struct scheduler *ops, int cpu) +{ if ( !alloc_cpumask_var(&_cpumask_scratch[cpu]) ) return ERR_PTR(-ENOMEM); @@ -1395,6 +1399,7 @@ static const struct scheduler sched_rtds_def = { .deinit = rt_deinit, .alloc_pdata = rt_alloc_pdata, .free_pdata = rt_free_pdata, + .init_pdata = rt_init_pdata, .alloc_domdata = rt_alloc_domdata, .free_domdata = rt_free_domdata, .init_domain = rt_dom_init,
by borrowing some of the code of .alloc_pdata, i.e., the bits that perform initializations, leaving only actual allocations in there, when any, which is the case for Credit1 and RTDS. On the other hand, in Credit2, since we don't really need any per-pCPU data allocation, everything that was being done in .alloc_pdata, is now done in .init_pdata. And the fact that now .alloc_pdata can be left undefined, allows us to just get rid of it. Still for Credit2, the fact that .init_pdata is called during CPU_STARTING (rather than CPU_UP_PREPARE) kills the need for the scheduler to setup a similar callback itself, simplifying the code. And thanks to such simplification, it is now also ok to move some of the logic meant at double checking that a cpu was (or was not) initialized, into ASSERTS (rather than an if() and a BUG_ON). Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com> --- Cc: George Dunlap <george.dunlap@eu.citrix.com> Cc: Meng Xu <mengxu@cis.upenn.edu> Cc: Juergen Gross <jgross@suse.com> --- xen/common/sched_credit.c | 20 +++++++++--- xen/common/sched_credit2.c | 72 +++----------------------------------------- xen/common/sched_rt.c | 9 ++++-- 3 files changed, 26 insertions(+), 75 deletions(-)