[Xen-devel] [PATCH v3 05/47] xen/sched: let pick_cpu return a scheduler resource

From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>, Tim Deegan <tim@xen.org>,
	Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wl@xen.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	George Dunlap <george.dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	Robert VanVossen <robert.vanvossen@dornerworks.com>,
	Dario Faggioli <dfaggioli@suse.com>,
	Julien Grall <julien.grall@arm.com>,
	Josh Whitehead <josh.whitehead@dornerworks.com>,
	Meng Xu <mengxu@cis.upenn.edu>, Jan Beulich <jbeulich@suse.com>
Subject: [Xen-devel] [PATCH v3 05/47] xen/sched: let pick_cpu return a scheduler resource
Date: Sat, 14 Sep 2019 10:52:09 +0200	[thread overview]
Message-ID: <20190914085251.18816-6-jgross@suse.com> (raw)
In-Reply-To: <20190914085251.18816-1-jgross@suse.com>

Instead of returning a physical cpu number let pick_cpu() return a
scheduler resource instead. Rename pick_cpu() to pick_resource() to
reflect that change.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>
---
V3:
- style fix (Jan Beulich)
---
 xen/common/sched_arinc653.c  | 13 +++++++------
 xen/common/sched_credit.c    | 16 ++++++++--------
 xen/common/sched_credit2.c   | 22 +++++++++++-----------
 xen/common/sched_null.c      | 23 ++++++++++++-----------
 xen/common/sched_rt.c        | 18 +++++++++---------
 xen/common/schedule.c        | 18 ++++++++++--------
 xen/include/xen/perfc_defn.h |  2 +-
 xen/include/xen/sched-if.h   | 10 +++++-----
 8 files changed, 63 insertions(+), 59 deletions(-)

diff --git a/xen/common/sched_arinc653.c b/xen/common/sched_arinc653.c
index cdf5c2cc97..9754aaa503 100644
--- a/xen/common/sched_arinc653.c
+++ b/xen/common/sched_arinc653.c
@@ -601,15 +601,16 @@ a653sched_do_schedule(
 }
 
 /**
- * Xen scheduler callback function to select a CPU for the VCPU to run on
+ * Xen scheduler callback function to select a resource for the VCPU to run on
  *
  * @param ops       Pointer to this instance of the scheduler structure
  * @param unit      Pointer to struct sched_unit
  *
- * @return          Number of selected physical CPU
+ * @return          Scheduler resource to run on
  */
-static int
-a653sched_pick_cpu(const struct scheduler *ops, const struct sched_unit *unit)
+static struct sched_resource *
+a653sched_pick_resource(const struct scheduler *ops,
+                        const struct sched_unit *unit)
 {
     struct vcpu *vc = unit->vcpu_list;
     cpumask_t *online;
@@ -627,7 +628,7 @@ a653sched_pick_cpu(const struct scheduler *ops, const struct sched_unit *unit)
          || (cpu >= nr_cpu_ids) )
         cpu = vc->processor;
 
-    return cpu;
+    return get_sched_res(cpu);
 }
 
 /**
@@ -720,7 +721,7 @@ static const struct scheduler sched_arinc653_def = {
 
     .do_schedule    = a653sched_do_schedule,
 
-    .pick_cpu       = a653sched_pick_cpu,
+    .pick_resource  = a653sched_pick_resource,
 
     .switch_sched   = a653_switch_sched,
 
diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index 2bc7fa9220..b34cc32ce0 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -853,8 +853,8 @@ _csched_cpu_pick(const struct scheduler *ops, struct vcpu *vc, bool_t commit)
     return cpu;
 }
 
-static int
-csched_cpu_pick(const struct scheduler *ops, const struct sched_unit *unit)
+static struct sched_resource *
+csched_res_pick(const struct scheduler *ops, const struct sched_unit *unit)
 {
     struct vcpu *vc = unit->vcpu_list;
     struct csched_vcpu *svc = CSCHED_VCPU(vc);
@@ -867,7 +867,7 @@ csched_cpu_pick(const struct scheduler *ops, const struct sched_unit *unit)
      * get boosted, which we don't deserve as we are "only" migrating.
      */
     set_bit(CSCHED_FLAG_VCPU_MIGRATING, &svc->flags);
-    return _csched_cpu_pick(ops, vc, 1);
+    return get_sched_res(_csched_cpu_pick(ops, vc, 1));
 }
 
 static inline void
@@ -967,7 +967,7 @@ csched_vcpu_acct(struct csched_private *prv, unsigned int cpu)
         /*
          * If it's been active a while, check if we'd be better off
          * migrating it to run elsewhere (see multi-core and multi-thread
-         * support in csched_cpu_pick()).
+         * support in csched_res_pick()).
          */
         new_cpu = _csched_cpu_pick(ops, current, 0);
 
@@ -1022,11 +1022,11 @@ csched_unit_insert(const struct scheduler *ops, struct sched_unit *unit)
 
     BUG_ON( is_idle_vcpu(vc) );
 
-    /* csched_cpu_pick() looks in vc->processor's runq, so we need the lock. */
+    /* csched_res_pick() looks in vc->processor's runq, so we need the lock. */
     lock = vcpu_schedule_lock_irq(vc);
 
-    vc->processor = csched_cpu_pick(ops, unit);
-    unit->res = get_sched_res(vc->processor);
+    unit->res = csched_res_pick(ops, unit);
+    vc->processor = unit->res->master_cpu;
 
     spin_unlock_irq(lock);
 
@@ -2278,7 +2278,7 @@ static const struct scheduler sched_credit_def = {
     .adjust_affinity= csched_aff_cntl,
     .adjust_global  = csched_sys_cntl,
 
-    .pick_cpu       = csched_cpu_pick,
+    .pick_resource  = csched_res_pick,
     .do_schedule    = csched_schedule,
 
     .dump_cpu_state = csched_dump_pcpu,
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 200de63bee..cea4a11087 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -626,9 +626,9 @@ static inline bool has_cap(const struct csched2_vcpu *svc)
  * runq, _always_ happens by means of tickling:
  *  - when a vcpu wakes up, it calls csched2_unit_wake(), which calls
  *    runq_tickle();
- *  - when a migration is initiated in schedule.c, we call csched2_cpu_pick(),
+ *  - when a migration is initiated in schedule.c, we call csched2_res_pick(),
  *    csched2_unit_migrate() (which calls migrate()) and csched2_unit_wake().
- *    csched2_cpu_pick() looks for the least loaded runq and return just any
+ *    csched2_res_pick() looks for the least loaded runq and return just any
  *    of its processors. Then, csched2_unit_migrate() just moves the vcpu to
  *    the chosen runq, and it is again runq_tickle(), called by
  *    csched2_unit_wake() that actually decides what pcpu to use within the
@@ -677,7 +677,7 @@ void smt_idle_mask_clear(unsigned int cpu, cpumask_t *mask)
 }
 
 /*
- * In csched2_cpu_pick(), it may not be possible to actually look at remote
+ * In csched2_res_pick(), it may not be possible to actually look at remote
  * runqueues (the trylock-s on their spinlocks can fail!). If that happens,
  * we pick, in order of decreasing preference:
  *  1) svc's current pcpu, if it is part of svc's soft affinity;
@@ -2202,8 +2202,8 @@ csched2_context_saved(const struct scheduler *ops, struct sched_unit *unit)
 }
 
 #define MAX_LOAD (STIME_MAX)
-static int
-csched2_cpu_pick(const struct scheduler *ops, const struct sched_unit *unit)
+static struct sched_resource *
+csched2_res_pick(const struct scheduler *ops, const struct sched_unit *unit)
 {
     struct csched2_private *prv = csched2_priv(ops);
     struct vcpu *vc = unit->vcpu_list;
@@ -2215,7 +2215,7 @@ csched2_cpu_pick(const struct scheduler *ops, const struct sched_unit *unit)
 
     ASSERT(!cpumask_empty(&prv->active_queues));
 
-    SCHED_STAT_CRANK(pick_cpu);
+    SCHED_STAT_CRANK(pick_resource);
 
     /* Locking:
      * - Runqueue lock of vc->processor is already locked
@@ -2424,7 +2424,7 @@ csched2_cpu_pick(const struct scheduler *ops, const struct sched_unit *unit)
                     (unsigned char *)&d);
     }
 
-    return new_cpu;
+    return get_sched_res(new_cpu);
 }
 
 /* Working state of the load-balancing algorithm */
@@ -3121,11 +3121,11 @@ csched2_unit_insert(const struct scheduler *ops, struct sched_unit *unit)
     ASSERT(!is_idle_vcpu(vc));
     ASSERT(list_empty(&svc->runq_elem));
 
-    /* csched2_cpu_pick() expects the pcpu lock to be held */
+    /* csched2_res_pick() expects the pcpu lock to be held */
     lock = vcpu_schedule_lock_irq(vc);
 
-    vc->processor = csched2_cpu_pick(ops, unit);
-    unit->res = get_sched_res(vc->processor);
+    unit->res = csched2_res_pick(ops, unit);
+    vc->processor = unit->res->master_cpu;
 
     spin_unlock_irq(lock);
 
@@ -4112,7 +4112,7 @@ static const struct scheduler sched_credit2_def = {
     .adjust_affinity= csched2_aff_cntl,
     .adjust_global  = csched2_sys_cntl,
 
-    .pick_cpu       = csched2_cpu_pick,
+    .pick_resource  = csched2_res_pick,
     .migrate        = csched2_unit_migrate,
     .do_schedule    = csched2_schedule,
     .context_saved  = csched2_context_saved,
diff --git a/xen/common/sched_null.c b/xen/common/sched_null.c
index c30fe2e443..3bb3a53452 100644
--- a/xen/common/sched_null.c
+++ b/xen/common/sched_null.c
@@ -261,9 +261,11 @@ static void null_free_domdata(const struct scheduler *ops, void *data)
  *
  * So this is not part of any hot path.
  */
-static unsigned int pick_cpu(struct null_private *prv, struct vcpu *v)
+static struct sched_resource *
+pick_res(struct null_private *prv, const struct sched_unit *unit)
 {
     unsigned int bs;
+    struct vcpu *v = unit->vcpu_list;
     unsigned int cpu = v->processor, new_cpu;
     cpumask_t *cpus = cpupool_domain_cpumask(v->domain);
 
@@ -327,7 +329,7 @@ static unsigned int pick_cpu(struct null_private *prv, struct vcpu *v)
         __trace_var(TRC_SNULL_PICKED_CPU, 1, sizeof(d), &d);
     }
 
-    return new_cpu;
+    return get_sched_res(new_cpu);
 }
 
 static void vcpu_assign(struct null_private *prv, struct vcpu *v,
@@ -457,8 +459,8 @@ static void null_unit_insert(const struct scheduler *ops,
     }
 
  retry:
-    cpu = v->processor = pick_cpu(prv, v);
-    unit->res = get_sched_res(cpu);
+    unit->res = pick_res(prv, unit);
+    cpu = v->processor = unit->res->master_cpu;
 
     spin_unlock(lock);
 
@@ -599,7 +601,7 @@ static void null_unit_wake(const struct scheduler *ops,
          */
         while ( cpumask_intersects(&prv->cpus_free, cpumask_scratch_cpu(cpu)) )
         {
-            unsigned int new_cpu = pick_cpu(prv, v);
+            unsigned int new_cpu = pick_res(prv, unit)->master_cpu;
 
             if ( test_and_clear_bit(new_cpu, &prv->cpus_free) )
             {
@@ -648,12 +650,11 @@ static void null_unit_sleep(const struct scheduler *ops,
     SCHED_STAT_CRANK(vcpu_sleep);
 }
 
-static int null_cpu_pick(const struct scheduler *ops,
-                         const struct sched_unit *unit)
+static struct sched_resource *
+null_res_pick(const struct scheduler *ops, const struct sched_unit *unit)
 {
-    struct vcpu *v = unit->vcpu_list;
-    ASSERT(!is_idle_vcpu(v));
-    return pick_cpu(null_priv(ops), v);
+    ASSERT(!is_idle_vcpu(unit->vcpu_list));
+    return pick_res(null_priv(ops), unit);
 }
 
 static void null_unit_migrate(const struct scheduler *ops,
@@ -985,7 +986,7 @@ static const struct scheduler sched_null_def = {
 
     .wake           = null_unit_wake,
     .sleep          = null_unit_sleep,
-    .pick_cpu       = null_cpu_pick,
+    .pick_resource  = null_res_pick,
     .migrate        = null_unit_migrate,
     .do_schedule    = null_schedule,
 
diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index 3ba76f1c4a..f303271399 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -631,12 +631,12 @@ replq_reinsert(const struct scheduler *ops, struct rt_vcpu *svc)
 }
 
 /*
- * Pick a valid CPU for the vcpu vc
- * Valid CPU of a vcpu is intesection of vcpu's affinity
- * and available cpus
+ * Pick a valid resource for the vcpu vc
+ * Valid resource of a vcpu is intesection of vcpu's affinity
+ * and available resources
  */
-static int
-rt_cpu_pick(const struct scheduler *ops, const struct sched_unit *unit)
+static struct sched_resource *
+rt_res_pick(const struct scheduler *ops, const struct sched_unit *unit)
 {
     struct vcpu *vc = unit->vcpu_list;
     cpumask_t cpus;
@@ -651,7 +651,7 @@ rt_cpu_pick(const struct scheduler *ops, const struct sched_unit *unit)
             : cpumask_cycle(vc->processor, &cpus);
     ASSERT( !cpumask_empty(&cpus) && cpumask_test_cpu(cpu, &cpus) );
 
-    return cpu;
+    return get_sched_res(cpu);
 }
 
 /*
@@ -892,8 +892,8 @@ rt_unit_insert(const struct scheduler *ops, struct sched_unit *unit)
     BUG_ON( is_idle_vcpu(vc) );
 
     /* This is safe because vc isn't yet being scheduled */
-    vc->processor = rt_cpu_pick(ops, unit);
-    unit->res = get_sched_res(vc->processor);
+    unit->res = rt_res_pick(ops, unit);
+    vc->processor = unit->res->master_cpu;
 
     lock = vcpu_schedule_lock_irq(vc);
 
@@ -1562,7 +1562,7 @@ static const struct scheduler sched_rtds_def = {
 
     .adjust         = rt_dom_cntl,
 
-    .pick_cpu       = rt_cpu_pick,
+    .pick_resource  = rt_res_pick,
     .do_schedule    = rt_schedule,
     .sleep          = rt_unit_sleep,
     .wake           = rt_unit_wake,
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 2bf7966476..b7cdc15bd1 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -87,10 +87,10 @@ sched_idle_switch_sched(struct scheduler *new_ops, unsigned int cpu,
     return &sched_free_cpu_lock;
 }
 
-static int
-sched_idle_cpu_pick(const struct scheduler *ops, const struct sched_unit *unit)
+static struct sched_resource *
+sched_idle_res_pick(const struct scheduler *ops, const struct sched_unit *unit)
 {
-    return unit->res->master_cpu;
+    return unit->res;
 }
 
 static void *
@@ -122,7 +122,7 @@ static struct scheduler sched_idle_ops = {
     .opt_name       = "idle",
     .sched_data     = NULL,
 
-    .pick_cpu       = sched_idle_cpu_pick,
+    .pick_resource  = sched_idle_res_pick,
     .do_schedule    = sched_idle_schedule,
 
     .alloc_vdata    = sched_idle_alloc_vdata,
@@ -746,7 +746,8 @@ static void vcpu_migrate_finish(struct vcpu *v)
                 break;
 
             /* Select a new CPU. */
-            new_cpu = sched_pick_cpu(vcpu_scheduler(v), v->sched_unit);
+            new_cpu = sched_pick_resource(vcpu_scheduler(v),
+                                          v->sched_unit)->master_cpu;
             if ( (new_lock == per_cpu(schedule_data, new_cpu).schedule_lock) &&
                  cpumask_test_cpu(new_cpu, v->domain->cpupool->cpu_valid) )
                 break;
@@ -839,8 +840,9 @@ void restore_vcpu_affinity(struct domain *d)
 
         /* v->processor might have changed, so reacquire the lock. */
         lock = vcpu_schedule_lock_irq(v);
-        v->processor = sched_pick_cpu(vcpu_scheduler(v), v->sched_unit);
-        v->sched_unit->res = get_sched_res(v->processor);
+        v->sched_unit->res = sched_pick_resource(vcpu_scheduler(v),
+                                                 v->sched_unit);
+        v->processor = v->sched_unit->res->master_cpu;
         spin_unlock_irq(lock);
 
         if ( old_cpu != v->processor )
@@ -1853,7 +1855,7 @@ void __init scheduler_init(void)
 
         sched_test_func(init);
         sched_test_func(deinit);
-        sched_test_func(pick_cpu);
+        sched_test_func(pick_resource);
         sched_test_func(alloc_vdata);
         sched_test_func(free_vdata);
         sched_test_func(switch_sched);
diff --git a/xen/include/xen/perfc_defn.h b/xen/include/xen/perfc_defn.h
index ef6f86b91e..1ad4384080 100644
--- a/xen/include/xen/perfc_defn.h
+++ b/xen/include/xen/perfc_defn.h
@@ -69,7 +69,7 @@ PERFCOUNTER(migrate_on_runq,        "csched2: migrate_on_runq")
 PERFCOUNTER(migrate_no_runq,        "csched2: migrate_no_runq")
 PERFCOUNTER(runtime_min_timer,      "csched2: runtime_min_timer")
 PERFCOUNTER(runtime_max_timer,      "csched2: runtime_max_timer")
-PERFCOUNTER(pick_cpu,               "csched2: pick_cpu")
+PERFCOUNTER(pick_resource,          "csched2: pick_resource")
 PERFCOUNTER(need_fallback_cpu,      "csched2: need_fallback_cpu")
 PERFCOUNTER(migrated,               "csched2: migrated")
 PERFCOUNTER(migrate_resisted,       "csched2: migrate_resisted")
diff --git a/xen/include/xen/sched-if.h b/xen/include/xen/sched-if.h
index b9e2920c66..2d9d77c6d3 100644
--- a/xen/include/xen/sched-if.h
+++ b/xen/include/xen/sched-if.h
@@ -189,8 +189,8 @@ struct scheduler {
     struct task_slice (*do_schedule) (const struct scheduler *, s_time_t,
                                       bool_t tasklet_work_scheduled);
 
-    int          (*pick_cpu)       (const struct scheduler *,
-                                    const struct sched_unit *);
+    struct sched_resource *(*pick_resource)(const struct scheduler *,
+                                            const struct sched_unit *);
     void         (*migrate)        (const struct scheduler *,
                                     struct sched_unit *, unsigned int);
     int          (*adjust)         (const struct scheduler *, struct domain *,
@@ -355,10 +355,10 @@ static inline void sched_migrate(const struct scheduler *s,
     }
 }
 
-static inline int sched_pick_cpu(const struct scheduler *s,
-                                 const struct sched_unit *unit)
+static inline struct sched_resource *sched_pick_resource(
+    const struct scheduler *s, const struct sched_unit *unit)
 {
-    return s->pick_cpu(s, unit);
+    return s->pick_resource(s, unit);
 }
 
 static inline void sched_adjust_affinity(const struct scheduler *s,
-- 
2.16.4


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