Message ID | 1560332150-27712-1-git-send-email-andrii.anisov@gmail.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | [v4] schedule: move credit scheduler specific member to its privates | expand |
On Wed, 2019-06-12 at 12:35 +0300, Andrii Anisov wrote: > From: Andrii Anisov <andrii_anisov@epam.com> > > The vcpu structure member last_run_time is used by credit scheduler > only. > In order to get better encapsulation, it is moved from a generic > structure to the credit scheduler private vcpu definition. Also, > rename > the member to last_sched_time in order to reflect that it is the time > when the vcpu went through the scheduling path. > > With this move we have slight changes in functionality: > - last_sched_time is not updated for an idle vcpu. But the idle vcpu > is, > in fact, a per-pcpu stub and never migrates so last_sched_time is > meaningless for it. > - The value of last_sched_time is updated on every schedule, even if > the > vcpu is not being changed. It is still ok, because last_sched_time > is > only used for runnable vcpu migration decision, and we have it > correct > at that moment. Scheduling parameters and statistics are tracked > by > other entities. > > Reducing code and data usage when not running credit scheduler is > another > nice side effect. > > While here, also: > - turn last_sched_time into s_time_t, which is more appropriate. > - properly const-ify related argument of > __csched_vcpu_is_cache_hot(). > > Signed-off-by: Andrii Anisov <andrii_anisov@epam.com> > Reviewed-by: Dario Faggioli <dfaggioli@suse.com> Thanks and Regards
diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c index 7b7facb..07e442c 100644 --- a/xen/common/sched_credit.c +++ b/xen/common/sched_credit.c @@ -175,6 +175,8 @@ struct csched_vcpu { atomic_t credit; unsigned int residual; + s_time_t last_sched_time; + #ifdef CSCHED_STATS struct { int credit_last; @@ -701,10 +703,11 @@ static unsigned int vcpu_migration_delay_us; integer_param("vcpu_migration_delay", vcpu_migration_delay_us); static inline bool -__csched_vcpu_is_cache_hot(const struct csched_private *prv, struct vcpu *v) +__csched_vcpu_is_cache_hot(const struct csched_private *prv, + const struct csched_vcpu *svc) { bool hot = prv->vcpu_migr_delay && - (NOW() - v->last_run_time) < prv->vcpu_migr_delay; + (NOW() - svc->last_sched_time) < prv->vcpu_migr_delay; if ( hot ) SCHED_STAT_CRANK(vcpu_hot); @@ -716,6 +719,7 @@ static inline int __csched_vcpu_is_migrateable(const struct csched_private *prv, struct vcpu *vc, int dest_cpu, cpumask_t *mask) { + const struct csched_vcpu *svc = CSCHED_VCPU(vc); /* * Don't pick up work that's hot on peer PCPU, or that can't (or * would prefer not to) run on cpu. @@ -725,7 +729,7 @@ __csched_vcpu_is_migrateable(const struct csched_private *prv, struct vcpu *vc, */ ASSERT(!vc->is_running); - return !__csched_vcpu_is_cache_hot(prv, vc) && + return !__csched_vcpu_is_cache_hot(prv, svc) && cpumask_test_cpu(dest_cpu, mask); } @@ -1870,6 +1874,7 @@ csched_schedule( /* Update credits of a non-idle VCPU. */ burn_credits(scurr, now); scurr->start_time -= now; + scurr->last_sched_time = now; } else { diff --git a/xen/common/schedule.c b/xen/common/schedule.c index ba942a7..047f767 100644 --- a/xen/common/schedule.c +++ b/xen/common/schedule.c @@ -1486,7 +1486,6 @@ static void schedule(void) ((prev->pause_flags & VPF_blocked) ? RUNSTATE_blocked : (vcpu_runnable(prev) ? RUNSTATE_runnable : RUNSTATE_offline)), now); - prev->last_run_time = now; ASSERT(next->runstate.state != RUNSTATE_running); vcpu_runstate_change(next, RUNSTATE_running, now); diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h index ccd5347..97a3ab5 100644 --- a/xen/include/xen/sched.h +++ b/xen/include/xen/sched.h @@ -174,9 +174,6 @@ struct vcpu } runstate_guest; /* guest address */ #endif - /* last time when vCPU is scheduled out */ - uint64_t last_run_time; - /* Has the FPU been initialised? */ bool fpu_initialised; /* Has the FPU been used since it was last saved? */