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[PATCH 05/10] sched/core: Remove the tsk_cpus_allowed() wrapper

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  [PATCH 05/10] sched/core: Remove the tsk_cpus_allowed() wrapper Ingo Molnar <mingo@kernel.org> - 2017-02-08 19:40 +0100
    Re: [PATCH 05/10] sched/core: Remove the tsk_cpus_allowed() wrapper Peter Zijlstra <peterz@infradead.org> - 2017-02-09 10:00 +0100
      Re: [PATCH 05/10] sched/core: Remove the tsk_cpus_allowed() wrapper Ingo Molnar <mingo@kernel.org> - 2017-02-09 10:10 +0100
        Re: [PATCH 05/10] sched/core: Remove the tsk_cpus_allowed()  wrapper Thomas Gleixner <tglx@linutronix.de> - 2017-02-09 12:50 +0100
          Re: [PATCH 05/10] sched/core: Remove the tsk_cpus_allowed() wrapper Ingo Molnar <mingo@kernel.org> - 2017-02-09 21:30 +0100

#1576813 — [PATCH 05/10] sched/core: Remove the tsk_cpus_allowed() wrapper

So the original intention of tsk_cpus_allowed() was to 'future-proof'
the field - but it's pretty ineffectual at that, because half of
the code uses ->cpus_allowed directly ...

Also, the wrapper makes the code longer than the original expression!

So just get rid of it. This also shrinks <linux/sched.h> a bit.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/powerpc/kernel/smp.c                  |  2 +-
 arch/powerpc/platforms/cell/spufs/sched.c  |  2 +-
 arch/sparc/kernel/sysfs.c                  |  2 +-
 drivers/cpufreq/sparc-us2e-cpufreq.c       |  4 ++--
 drivers/cpufreq/sparc-us3-cpufreq.c        |  4 ++--
 drivers/infiniband/hw/hfi1/affinity.c      |  2 +-
 drivers/infiniband/hw/hfi1/sdma.c          |  2 +-
 include/linux/sched.h                      |  3 ---
 kernel/sched/core.c                        | 20 ++++++++++----------
 kernel/sched/cpudeadline.c                 |  4 ++--
 kernel/sched/cpupri.c                      |  4 ++--
 kernel/sched/deadline.c                    |  7 +++----
 kernel/sched/fair.c                        | 25 ++++++++++++-------------
 kernel/sched/rt.c                          |  5 ++---
 lib/smp_processor_id.c                     |  2 +-
 samples/trace_events/trace-events-sample.c |  2 +-
 16 files changed, 42 insertions(+), 48 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 893bd7f79be6..b7d8f867742d 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -795,7 +795,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 	 * se we pin us down to CPU 0 for a short while
 	 */
 	alloc_cpumask_var(&old_mask, GFP_NOWAIT);
-	cpumask_copy(old_mask, tsk_cpus_allowed(current));
+	cpumask_copy(old_mask, &current->cpus_allowed);
 	set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
 	
 	if (smp_ops && smp_ops->setup_cpu)
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 460f5f31d5cb..9b543df210fb 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -140,7 +140,7 @@ void __spu_update_sched_info(struct spu_context *ctx)
 	 * runqueue. The context will be rescheduled on the proper node
 	 * if it is timesliced or preempted.
 	 */
-	cpumask_copy(&ctx->cpus_allowed, tsk_cpus_allowed(current));
+	cpumask_copy(&ctx->cpus_allowed, &current->cpus_allowed);
 
 	/* Save the current cpu id for spu interrupt routing. */
 	ctx->last_ran = raw_smp_processor_id();
diff --git a/arch/sparc/kernel/sysfs.c b/arch/sparc/kernel/sysfs.c
index 4808b6d23455..d63fc613e7a9 100644
--- a/arch/sparc/kernel/sysfs.c
+++ b/arch/sparc/kernel/sysfs.c
@@ -106,7 +106,7 @@ static unsigned long run_on_cpu(unsigned long cpu,
 	cpumask_t old_affinity;
 	unsigned long ret;
 
-	cpumask_copy(&old_affinity, tsk_cpus_allowed(current));
+	cpumask_copy(&old_affinity, &current->cpus_allowed);
 	/* should return -EINVAL to userspace */
 	if (set_cpus_allowed_ptr(current, cpumask_of(cpu)))
 		return 0;
diff --git a/drivers/cpufreq/sparc-us2e-cpufreq.c b/drivers/cpufreq/sparc-us2e-cpufreq.c
index b73feeb666f9..35ddb6da93aa 100644
--- a/drivers/cpufreq/sparc-us2e-cpufreq.c
+++ b/drivers/cpufreq/sparc-us2e-cpufreq.c
@@ -234,7 +234,7 @@ static unsigned int us2e_freq_get(unsigned int cpu)
 	cpumask_t cpus_allowed;
 	unsigned long clock_tick, estar;
 
-	cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
+	cpumask_copy(&cpus_allowed, &current->cpus_allowed);
 	set_cpus_allowed_ptr(current, cpumask_of(cpu));
 
 	clock_tick = sparc64_get_clock_tick(cpu) / 1000;
@@ -252,7 +252,7 @@ static int us2e_freq_target(struct cpufreq_policy *policy, unsigned int index)
 	unsigned long clock_tick, divisor, old_divisor, estar;
 	cpumask_t cpus_allowed;
 
-	cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
+	cpumask_copy(&cpus_allowed, &current->cpus_allowed);
 	set_cpus_allowed_ptr(current, cpumask_of(cpu));
 
 	new_freq = clock_tick = sparc64_get_clock_tick(cpu) / 1000;
diff --git a/drivers/cpufreq/sparc-us3-cpufreq.c b/drivers/cpufreq/sparc-us3-cpufreq.c
index 9bb42ba50efa..a8d86a449ca1 100644
--- a/drivers/cpufreq/sparc-us3-cpufreq.c
+++ b/drivers/cpufreq/sparc-us3-cpufreq.c
@@ -82,7 +82,7 @@ static unsigned int us3_freq_get(unsigned int cpu)
 	unsigned long reg;
 	unsigned int ret;
 
-	cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
+	cpumask_copy(&cpus_allowed, &current->cpus_allowed);
 	set_cpus_allowed_ptr(current, cpumask_of(cpu));
 
 	reg = read_safari_cfg();
@@ -99,7 +99,7 @@ static int us3_freq_target(struct cpufreq_policy *policy, unsigned int index)
 	unsigned long new_bits, new_freq, reg;
 	cpumask_t cpus_allowed;
 
-	cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
+	cpumask_copy(&cpus_allowed, &current->cpus_allowed);
 	set_cpus_allowed_ptr(current, cpumask_of(cpu));
 
 	new_freq = sparc64_get_clock_tick(cpu) / 1000;
diff --git a/drivers/infiniband/hw/hfi1/affinity.c b/drivers/infiniband/hw/hfi1/affinity.c
index 7a3d906b3671..e2cd2cd3b28a 100644
--- a/drivers/infiniband/hw/hfi1/affinity.c
+++ b/drivers/infiniband/hw/hfi1/affinity.c
@@ -576,7 +576,7 @@ int hfi1_get_proc_affinity(int node)
 	struct hfi1_affinity_node *entry;
 	cpumask_var_t diff, hw_thread_mask, available_mask, intrs_mask;
 	const struct cpumask *node_mask,
-		*proc_mask = tsk_cpus_allowed(current);
+		*proc_mask = &current->cpus_allowed;
 	struct hfi1_affinity_node_list *affinity = &node_affinity;
 	struct cpu_mask_set *set = &affinity->proc;
 
diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c
index 1d81cac1fa6c..5cde1ecda0fe 100644
--- a/drivers/infiniband/hw/hfi1/sdma.c
+++ b/drivers/infiniband/hw/hfi1/sdma.c
@@ -856,7 +856,7 @@ struct sdma_engine *sdma_select_user_engine(struct hfi1_devdata *dd,
 {
 	struct sdma_rht_node *rht_node;
 	struct sdma_engine *sde = NULL;
-	const struct cpumask *current_mask = tsk_cpus_allowed(current);
+	const struct cpumask *current_mask = &current->cpus_allowed;
 	unsigned long cpu_id;
 
 	/*
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7710d52ad0c3..38af022b351d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1999,9 +1999,6 @@ static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 }
 #endif
 
-/* Future-safe accessor for struct task_struct's cpus_allowed. */
-#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
-
 static inline int tsk_nr_cpus_allowed(struct task_struct *p)
 {
 	return p->nr_cpus_allowed;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5c010ca5b126..0706863f83b5 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -978,7 +978,7 @@ static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int dest_
 		return rq;
 
 	/* Affinity changed (again). */
-	if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
+	if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
 		return rq;
 
 	rq = move_queued_task(rq, p, dest_cpu);
@@ -1255,10 +1255,10 @@ static int migrate_swap_stop(void *data)
 	if (task_cpu(arg->src_task) != arg->src_cpu)
 		goto unlock;
 
-	if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task)))
+	if (!cpumask_test_cpu(arg->dst_cpu, &arg->src_task->cpus_allowed))
 		goto unlock;
 
-	if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task)))
+	if (!cpumask_test_cpu(arg->src_cpu, &arg->dst_task->cpus_allowed))
 		goto unlock;
 
 	__migrate_swap_task(arg->src_task, arg->dst_cpu);
@@ -1299,10 +1299,10 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p)
 	if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu))
 		goto out;
 
-	if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task)))
+	if (!cpumask_test_cpu(arg.dst_cpu, &arg.src_task->cpus_allowed))
 		goto out;
 
-	if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task)))
+	if (!cpumask_test_cpu(arg.src_cpu, &arg.dst_task->cpus_allowed))
 		goto out;
 
 	trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu);
@@ -1486,14 +1486,14 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
 		for_each_cpu(dest_cpu, nodemask) {
 			if (!cpu_active(dest_cpu))
 				continue;
-			if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
+			if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
 				return dest_cpu;
 		}
 	}
 
 	for (;;) {
 		/* Any allowed, online CPU? */
-		for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) {
+		for_each_cpu(dest_cpu, &p->cpus_allowed) {
 			if (!(p->flags & PF_KTHREAD) && !cpu_active(dest_cpu))
 				continue;
 			if (!cpu_online(dest_cpu))
@@ -1548,7 +1548,7 @@ int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
 	if (tsk_nr_cpus_allowed(p) > 1)
 		cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags);
 	else
-		cpu = cpumask_any(tsk_cpus_allowed(p));
+		cpu = cpumask_any(&p->cpus_allowed);
 
 	/*
 	 * In order not to call set_task_cpu() on a blocking task we need
@@ -1560,7 +1560,7 @@ int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
 	 * [ this allows ->select_task() to simply return task_cpu(p) and
 	 *   not worry about this generic constraint ]
 	 */
-	if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||
+	if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) ||
 		     !cpu_online(cpu)))
 		cpu = select_fallback_rq(task_cpu(p), p);
 
@@ -5469,7 +5469,7 @@ int migrate_task_to(struct task_struct *p, int target_cpu)
 	if (curr_cpu == target_cpu)
 		return 0;
 
-	if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p)))
+	if (!cpumask_test_cpu(target_cpu, &p->cpus_allowed))
 		return -EINVAL;
 
 	/* TODO: This is not properly updating schedstats */
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index e73119013c53..fba235c7d026 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -128,10 +128,10 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
 	const struct sched_dl_entity *dl_se = &p->dl;
 
 	if (later_mask &&
-	    cpumask_and(later_mask, cp->free_cpus, tsk_cpus_allowed(p))) {
+	    cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
 		best_cpu = cpumask_any(later_mask);
 		goto out;
-	} else if (cpumask_test_cpu(cpudl_maximum(cp), tsk_cpus_allowed(p)) &&
+	} else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
 			dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
 		best_cpu = cpudl_maximum(cp);
 		if (later_mask)
diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c
index 11e9705bf937..981fcd7dc394 100644
--- a/kernel/sched/cpupri.c
+++ b/kernel/sched/cpupri.c
@@ -103,11 +103,11 @@ int cpupri_find(struct cpupri *cp, struct task_struct *p,
 		if (skip)
 			continue;
 
-		if (cpumask_any_and(tsk_cpus_allowed(p), vec->mask) >= nr_cpu_ids)
+		if (cpumask_any_and(&p->cpus_allowed, vec->mask) >= nr_cpu_ids)
 			continue;
 
 		if (lowest_mask) {
-			cpumask_and(lowest_mask, tsk_cpus_allowed(p), vec->mask);
+			cpumask_and(lowest_mask, &p->cpus_allowed, vec->mask);
 
 			/*
 			 * We have to ensure that we have at least one bit
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 27737f34757d..8e4d6e4e3ccc 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -252,7 +252,7 @@ static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p
 		 * If we cannot preempt any rq, fall back to pick any
 		 * online cpu.
 		 */
-		cpu = cpumask_any_and(cpu_active_mask, tsk_cpus_allowed(p));
+		cpu = cpumask_any_and(cpu_active_mask, &p->cpus_allowed);
 		if (cpu >= nr_cpu_ids) {
 			/*
 			 * Fail to find any suitable cpu.
@@ -1235,7 +1235,7 @@ static void set_curr_task_dl(struct rq *rq)
 static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu)
 {
 	if (!task_running(rq, p) &&
-	    cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
+	    cpumask_test_cpu(cpu, &p->cpus_allowed))
 		return 1;
 	return 0;
 }
@@ -1384,8 +1384,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
 		/* Retry if something changed. */
 		if (double_lock_balance(rq, later_rq)) {
 			if (unlikely(task_rq(task) != rq ||
-				     !cpumask_test_cpu(later_rq->cpu,
-						       tsk_cpus_allowed(task)) ||
+				     !cpumask_test_cpu(later_rq->cpu, &task->cpus_allowed) ||
 				     task_running(rq, task) ||
 				     !dl_task(task) ||
 				     !task_on_rq_queued(task))) {
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 274c747a01ce..3b60d73ab290 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1551,7 +1551,7 @@ static void task_numa_compare(struct task_numa_env *env,
 	 */
 	if (cur) {
 		/* Skip this swap candidate if cannot move to the source cpu */
-		if (!cpumask_test_cpu(env->src_cpu, tsk_cpus_allowed(cur)))
+		if (!cpumask_test_cpu(env->src_cpu, &cur->cpus_allowed))
 			goto unlock;
 
 		/*
@@ -1661,7 +1661,7 @@ static void task_numa_find_cpu(struct task_numa_env *env,
 
 	for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) {
 		/* Skip this CPU if the source task cannot migrate */
-		if (!cpumask_test_cpu(cpu, tsk_cpus_allowed(env->p)))
+		if (!cpumask_test_cpu(cpu, &env->p->cpus_allowed))
 			continue;
 
 		env->dst_cpu = cpu;
@@ -5458,7 +5458,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
 
 		/* Skip over this group if it has no CPUs allowed */
 		if (!cpumask_intersects(sched_group_cpus(group),
-					tsk_cpus_allowed(p)))
+					&p->cpus_allowed))
 			continue;
 
 		local_group = cpumask_test_cpu(this_cpu,
@@ -5578,7 +5578,7 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
 		return cpumask_first(sched_group_cpus(group));
 
 	/* Traverse only the allowed CPUs */
-	for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) {
+	for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) {
 		if (idle_cpu(i)) {
 			struct rq *rq = cpu_rq(i);
 			struct cpuidle_state *idle = idle_get_state(rq);
@@ -5717,7 +5717,7 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int
 	if (!test_idle_cores(target, false))
 		return -1;
 
-	cpumask_and(cpus, sched_domain_span(sd), tsk_cpus_allowed(p));
+	cpumask_and(cpus, sched_domain_span(sd), &p->cpus_allowed);
 
 	for_each_cpu_wrap(core, cpus, target, wrap) {
 		bool idle = true;
@@ -5751,7 +5751,7 @@ static int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int t
 		return -1;
 
 	for_each_cpu(cpu, cpu_smt_mask(target)) {
-		if (!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
+		if (!cpumask_test_cpu(cpu, &p->cpus_allowed))
 			continue;
 		if (idle_cpu(cpu))
 			return cpu;
@@ -5803,7 +5803,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t
 	time = local_clock();
 
 	for_each_cpu_wrap(cpu, sched_domain_span(sd), target, wrap) {
-		if (!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
+		if (!cpumask_test_cpu(cpu, &p->cpus_allowed))
 			continue;
 		if (idle_cpu(cpu))
 			break;
@@ -5958,7 +5958,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
 	if (sd_flag & SD_BALANCE_WAKE) {
 		record_wakee(p);
 		want_affine = !wake_wide(p) && !wake_cap(p, cpu, prev_cpu)
-			      && cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
+			      && cpumask_test_cpu(cpu, &p->cpus_allowed);
 	}
 
 	rcu_read_lock();
@@ -6698,7 +6698,7 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
 	if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu))
 		return 0;
 
-	if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) {
+	if (!cpumask_test_cpu(env->dst_cpu, &p->cpus_allowed)) {
 		int cpu;
 
 		schedstat_inc(p->se.statistics.nr_failed_migrations_affine);
@@ -6718,7 +6718,7 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
 
 		/* Prevent to re-select dst_cpu via env's cpus */
 		for_each_cpu_and(cpu, env->dst_grpmask, env->cpus) {
-			if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) {
+			if (cpumask_test_cpu(cpu, &p->cpus_allowed)) {
 				env->flags |= LBF_DST_PINNED;
 				env->new_dst_cpu = cpu;
 				break;
@@ -7252,7 +7252,7 @@ check_cpu_capacity(struct rq *rq, struct sched_domain *sd)
 
 /*
  * Group imbalance indicates (and tries to solve) the problem where balancing
- * groups is inadequate due to tsk_cpus_allowed() constraints.
+ * groups is inadequate due to ->cpus_allowed constraints.
  *
  * Imagine a situation of two groups of 4 cpus each and 4 tasks each with a
  * cpumask covering 1 cpu of the first group and 3 cpus of the second group.
@@ -8211,8 +8211,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
 			 * if the curr task on busiest cpu can't be
 			 * moved to this_cpu
 			 */
-			if (!cpumask_test_cpu(this_cpu,
-					tsk_cpus_allowed(busiest->curr))) {
+			if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) {
 				raw_spin_unlock_irqrestore(&busiest->lock,
 							    flags);
 				env.flags |= LBF_ALL_PINNED;
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index e8836cfc4cdb..cbd356f63883 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1591,7 +1591,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
 static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
 {
 	if (!task_running(rq, p) &&
-	    cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
+	    cpumask_test_cpu(cpu, &p->cpus_allowed))
 		return 1;
 	return 0;
 }
@@ -1726,8 +1726,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
 			 * Also make sure that it wasn't scheduled on its rq.
 			 */
 			if (unlikely(task_rq(task) != rq ||
-				     !cpumask_test_cpu(lowest_rq->cpu,
-						       tsk_cpus_allowed(task)) ||
+				     !cpumask_test_cpu(lowest_rq->cpu, &task->cpus_allowed) ||
 				     task_running(rq, task) ||
 				     !rt_task(task) ||
 				     !task_on_rq_queued(task))) {
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 1afec32de6f2..690d75b132fa 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -22,7 +22,7 @@ notrace static unsigned int check_preemption_disabled(const char *what1,
 	 * Kernel threads bound to a single CPU can safely use
 	 * smp_processor_id():
 	 */
-	if (cpumask_equal(tsk_cpus_allowed(current), cpumask_of(this_cpu)))
+	if (cpumask_equal(&current->cpus_allowed, cpumask_of(this_cpu)))
 		goto out;
 
 	/*
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index 30e282d33d4d..bc7fcf010a5b 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -33,7 +33,7 @@ static void simple_thread_func(int cnt)
 
 	/* Silly tracepoints */
 	trace_foo_bar("hello", cnt, array, random_strings[len],
-		      tsk_cpus_allowed(current));
+		      &current->cpus_allowed);
 
 	trace_foo_with_template_simple("HELLO", cnt);
 
-- 
2.7.4

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#1577379

On Wed, Feb 08, 2017 at 07:34:18PM +0100, Ingo Molnar wrote:
> So the original intention of tsk_cpus_allowed() was to 'future-proof'
> the field - but it's pretty ineffectual at that, because half of
> the code uses ->cpus_allowed directly ...
> 
> Also, the wrapper makes the code longer than the original expression!

I still object to taking this out without replacement. This leaves RT
stranded.

If you want to implement it differently do that, but don't blindly wreck
stuff for them.

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#1577390

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Wed, Feb 08, 2017 at 07:34:18PM +0100, Ingo Molnar wrote:
>
> > So the original intention of tsk_cpus_allowed() was to 'future-proof' the 
> > field - but it's pretty ineffectual at that, because half of the code uses 
> > ->cpus_allowed directly ...
> > 
> > Also, the wrapper makes the code longer than the original expression!
> 
> I still object to taking this out without replacement.

Yeah, that would have been my next suggestion.

> This leaves RT stranded.

Well, no, it leaves -rt with slightly more patching work than it already has...

Because note how the wrappery is _already_ incomplete to a significant degree:

  triton:~/tip> git grep -Ee '->cpus_allowed' | grep -vE 'tsk_|cpuset|core.c' | wc -l
  27
  triton:~/tip> git grep tsk_cpus_allowed | wc -l
  43

I.e. around 40% of the places that use ->cpus_allowed in the upstream kernel are 
not properly wrapped. That fact already 'wrecks' -rt.

Thanks,

	Ingo

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#1577492 — Re: [PATCH 05/10] sched/core: Remove the tsk_cpus_allowed() wrapper

On Thu, 9 Feb 2017, Ingo Molnar wrote:
> 
> * Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > On Wed, Feb 08, 2017 at 07:34:18PM +0100, Ingo Molnar wrote:
> >
> > > So the original intention of tsk_cpus_allowed() was to 'future-proof' the 
> > > field - but it's pretty ineffectual at that, because half of the code uses 
> > > ->cpus_allowed directly ...
> > > 
> > > Also, the wrapper makes the code longer than the original expression!
> > 
> > I still object to taking this out without replacement.
> 
> Yeah, that would have been my next suggestion.
> 
> > This leaves RT stranded.
> 
> Well, no, it leaves -rt with slightly more patching work than it already has...
> 
> Because note how the wrappery is _already_ incomplete to a significant degree:
> 
>   triton:~/tip> git grep -Ee '->cpus_allowed' | grep -vE 'tsk_|cpuset|core.c' | wc -l
>   27
>   triton:~/tip> git grep tsk_cpus_allowed | wc -l
>   43
> 
> I.e. around 40% of the places that use ->cpus_allowed in the upstream kernel are 
> not properly wrapped. That fact already 'wrecks' -rt.

Nope it does not. The places which use cpumask directly are not interfering
with the decisions which are made by the scheduler whether migration can
happen or not. All decision code pathes use the wrapper and we make sure on
every update that this is the case.

I completely agree that your idea with the const *ptr is the better
solution, but without that replacement RT is stranded and left alone with
the mop up.

Thanks,

	tglx

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#1577932

* Thomas Gleixner <tglx@linutronix.de> wrote:

> On Thu, 9 Feb 2017, Ingo Molnar wrote:
> > 
> > * Peter Zijlstra <peterz@infradead.org> wrote:
> > 
> > > On Wed, Feb 08, 2017 at 07:34:18PM +0100, Ingo Molnar wrote:
> > >
> > > > So the original intention of tsk_cpus_allowed() was to 'future-proof' the 
> > > > field - but it's pretty ineffectual at that, because half of the code uses 
> > > > ->cpus_allowed directly ...
> > > > 
> > > > Also, the wrapper makes the code longer than the original expression!
> > > 
> > > I still object to taking this out without replacement.
> > 
> > Yeah, that would have been my next suggestion.
> > 
> > > This leaves RT stranded.
> > 
> > Well, no, it leaves -rt with slightly more patching work than it already has...
> > 
> > Because note how the wrappery is _already_ incomplete to a significant degree:
> > 
> >   triton:~/tip> git grep -Ee '->cpus_allowed' | grep -vE 'tsk_|cpuset|core.c' | wc -l
> >   27
> >   triton:~/tip> git grep tsk_cpus_allowed | wc -l
> >   43
> > 
> > I.e. around 40% of the places that use ->cpus_allowed in the upstream kernel are 
> > not properly wrapped. That fact already 'wrecks' -rt.
> 
> Nope it does not. The places which use cpumask directly are not interfering with 
> the decisions which are made by the scheduler whether migration can happen or 
> not. All decision code pathes use the wrapper and we make sure on every update 
> that this is the case.

Indeed!

> I completely agree that your idea with the const *ptr is the better solution, 
> but without that replacement RT is stranded and left alone with the mop up.

Ok, I'm convinced!

Thanks,

	Ingo

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