[RFC][PATCH] sched: Cache aware load-balancing

Peter Zijlstra
2025-03-25T12:10:11Z

Hi all,

One of the many things on the eternal todo list has been finishing the
below hackery.

It is an attempt at modelling cache affinity -- and while the patch
really only targets LLC, it could very well be extended to also apply to
clusters (L2). Specifically any case of multiple cache domains inside a
node.

Anyway, I wrote this about a year ago, and I mentioned this at the
recent OSPM conf where Gautham and Prateek expressed interest in playing
with this code.

So here goes, very rough and largely unproven code ahead :-)

It applies to current tip/master, but I know it will fail the __percpu
validation that sits in -next, although that shouldn't be terribly hard
to fix up.

As is, it only computes a CPU inside the LLC that has the highest recent
runtime, this CPU is then used in the wake-up path to steer towards this
LLC and in task_hot() to limit migrations away from it.

More elaborate things could be done, notably there is an XXX in there
somewhere about finding the best LLC inside a NODE (interaction with
NUMA_BALANCING).

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/mm_types.h | 44 +++++++
include/linux/sched.h | 4 +
init/Kconfig | 4 +
kernel/fork.c | 5 +
kernel/sched/core.c | 13 +-
kernel/sched/fair.c | 330 ++++++++++++++++++++++++++++++++++++++++++++---
kernel/sched/sched.h | 8 ++
7 files changed, 388 insertions(+), 20 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 0234f14f2aa6..3ed8dd225eb9 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -800,6 +800,12 @@ struct mm_cid {
};
#endif

+struct mm_sched {
+ u64 runtime;
+ unsigned long epoch;
+ unsigned long occ;
+};
+
struct kioctx_table;
struct iommu_mm_data;
struct mm_struct {
@@ -890,6 +896,17 @@ struct mm_struct {
*/
raw_spinlock_t cpus_allowed_lock;
#endif
+#ifdef CONFIG_SCHED_CACHE
+ /*
+ * Track per-cpu-per-process occupancy as a proxy for cache residency.
+ * See account_mm_sched() and ...
+ */
+ struct mm_sched __percpu *pcpu_sched;
+ raw_spinlock_t mm_sched_lock;
+ unsigned long mm_sched_epoch;
+ int mm_sched_cpu;
+#endif
+
#ifdef CONFIG_MMU
atomic_long_t pgtables_bytes; /* size of all page tables */
#endif
@@ -1296,6 +1313,33 @@ static inline unsigned int mm_cid_size(void)
static inline void mm_set_cpus_allowed(struct mm_struct *mm, const struct cpumask *cpumask) { }
#endif /* CONFIG_SCHED_MM_CID */

+#ifdef CONFIG_SCHED_CACHE
+extern void mm_init_sched(struct mm_struct *mm, struct mm_sched *pcpu_sched);
+
+static inline int mm_alloc_sched_noprof(struct mm_struct *mm)
+{
+ struct mm_sched *pcpu_sched = alloc_percpu_noprof(struct mm_sched);
+ if (!pcpu_sched)
+ return -ENOMEM;
+
+ mm_init_sched(mm, pcpu_sched);
+ return 0;
+}
+
+#define mm_alloc_sched(...) alloc_hooks(mm_alloc_sched_noprof(__VA_ARGS__))
+
+static inline void mm_destroy_sched(struct mm_struct *mm)
+{
+ free_percpu(mm->pcpu_sched);
+ mm->pcpu_sched = NULL;
+}
+#else /* !CONFIG_SCHED_CACHE */
+
+static inline int mm_alloc_sched(struct mm_struct *mm) { return 0; }
+static inline void mm_destroy_sched(struct mm_struct *mm) { }
+
+#endif /* CONFIG_SCHED_CACHE */
+
struct mmu_gather;
extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6e5c38718ff5..f8eafe440369 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1379,6 +1379,10 @@ struct task_struct {
unsigned long numa_pages_migrated;
#endif /* CONFIG_NUMA_BALANCING */

+#ifdef CONFIG_SCHED_CACHE
+ struct callback_head cache_work;
+#endif
+
#ifdef CONFIG_RSEQ
struct rseq __user *rseq;
u32 rseq_len;
diff --git a/init/Kconfig b/init/Kconfig
index 681f38ee68db..14b15215318f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -950,6 +950,10 @@ config NUMA_BALANCING

This system will be inactive on UMA systems.

+config SCHED_CACHE
+ bool "Cache aware scheduler"
+ default y
+
config NUMA_BALANCING_DEFAULT_ENABLED
bool "Automatically enable NUMA aware memory/task placement"
default y
diff --git a/kernel/fork.c b/kernel/fork.c
index 1b659b07ecd5..bc9d7dbfd980 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1314,6 +1314,9 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
if (mm_alloc_cid(mm, p))
goto fail_cid;

+ if (mm_alloc_sched(mm))
+ goto fail_sched;
+
if (percpu_counter_init_many(mm->rss_stat, 0, GFP_KERNEL_ACCOUNT,
NR_MM_COUNTERS))
goto fail_pcpu;
@@ -1323,6 +1326,8 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
return mm;

fail_pcpu:
+ mm_destroy_sched(mm);
+fail_sched:
mm_destroy_cid(mm);
fail_cid:
destroy_context(mm);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 87540217fc09..649db6ea41ea 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4514,6 +4514,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
p->migration_pending = NULL;
#endif
init_sched_mm_cid(p);
+ init_sched_mm(p);
}

DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
@@ -8505,6 +8506,7 @@ static struct kmem_cache *task_group_cache __ro_after_init;

void __init sched_init(void)
{
+ unsigned long now = jiffies;
unsigned long ptr = 0;
int i;

@@ -8579,7 +8581,7 @@ void __init sched_init(void)
raw_spin_lock_init(&rq->__lock);
rq->nr_running = 0;
rq->calc_load_active = 0;
- rq->calc_load_update = jiffies + LOAD_FREQ;
+ rq->calc_load_update = now + LOAD_FREQ;
init_cfs_rq(&rq->cfs);
init_rt_rq(&rq->rt);
init_dl_rq(&rq->dl);
@@ -8623,7 +8625,7 @@ void __init sched_init(void)
rq->cpu_capacity = SCHED_CAPACITY_SCALE;
rq->balance_callback = &balance_push_callback;
rq->active_balance = 0;
- rq->next_balance = jiffies;
+ rq->next_balance = now;
rq->push_cpu = 0;
rq->cpu = i;
rq->online = 0;
@@ -8635,7 +8637,7 @@ void __init sched_init(void)

rq_attach_root(rq, &def_root_domain);
#ifdef CONFIG_NO_HZ_COMMON
- rq->last_blocked_load_update_tick = jiffies;
+ rq->last_blocked_load_update_tick = now;
atomic_set(&rq->nohz_flags, 0);

INIT_CSD(&rq->nohz_csd, nohz_csd_func, rq);
@@ -8660,6 +8662,11 @@ void __init sched_init(void)

rq->core_cookie = 0UL;
#endif
+#ifdef CONFIG_SCHED_CACHE
+ raw_spin_lock_init(&rq->cpu_epoch_lock);
+ rq->cpu_epoch_next = now;
+#endif
+
zalloc_cpumask_var_node(&rq->scratch_mask, GFP_KERNEL, cpu_to_node(i));
}

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e43993a4e580..943af076e09c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1166,10 +1166,229 @@ static s64 update_curr_se(struct rq *rq, struct sched_entity *curr)
return delta_exec;
}

-static inline void update_curr_task(struct task_struct *p, s64 delta_exec)
+#ifdef CONFIG_SCHED_CACHE
+
+/*
+ * XXX numbers come from a place the sun don't shine -- probably wants to be SD
+ * tunable or so.
+ */
+#define EPOCH_PERIOD (HZ/100) /* 10 ms */
+#define EPOCH_OLD 5 /* 50 ms */
+
+void mm_init_sched(struct mm_struct *mm, struct mm_sched *_pcpu_sched)
+{
+ unsigned long epoch;
+ int i;
+
+ for_each_possible_cpu(i) {
+ struct mm_sched *pcpu_sched = per_cpu_ptr(_pcpu_sched, i);
+ struct rq *rq = cpu_rq(i);
+
+ pcpu_sched->runtime = 0;
+ pcpu_sched->epoch = epoch = rq->cpu_epoch;
+ pcpu_sched->occ = -1;
+ }
+
+ raw_spin_lock_init(&mm->mm_sched_lock);
+ mm->mm_sched_epoch = epoch;
+ mm->mm_sched_cpu = -1;
+
+ smp_store_release(&mm->pcpu_sched, _pcpu_sched);
+}
+
+/* because why would C be fully specified */
+static __always_inline void __shr_u64(u64 *val, unsigned int n)
+{
+ if (n >= 64) {
+ *val = 0;
+ return;
+ }
+ *val >>= n;
+}
+
+static inline void __update_mm_sched(struct rq *rq, struct mm_sched *pcpu_sched)
+{
+ lockdep_assert_held(&rq->cpu_epoch_lock);
+
+ unsigned long n, now = jiffies;
+ long delta = now - rq->cpu_epoch_next;
+
+ if (delta > 0) {
+ n = (delta + EPOCH_PERIOD - 1) / EPOCH_PERIOD;
+ rq->cpu_epoch += n;
+ rq->cpu_epoch_next += n * EPOCH_PERIOD;
+ __shr_u64(&rq->cpu_runtime, n);
+ }
+
+ n = rq->cpu_epoch - pcpu_sched->epoch;
+ if (n) {
+ pcpu_sched->epoch += n;
+ __shr_u64(&pcpu_sched->runtime, n);
+ }
+}
+
+static unsigned long fraction_mm_sched(struct rq *rq, struct mm_sched *pcpu_sched)
+{
+ guard(raw_spinlock_irqsave)(&rq->cpu_epoch_lock);
+
+ __update_mm_sched(rq, pcpu_sched);
+
+ /*
+ * Runtime is a geometric series (r=0.5) and as such will sum to twice
+ * the accumulation period, this means the multiplcation here should
+ * not overflow.
+ */
+ return div64_u64(NICE_0_LOAD * pcpu_sched->runtime, rq->cpu_runtime + 1);
+}
+
+static inline
+void account_mm_sched(struct rq *rq, struct task_struct *p, s64 delta_exec)
+{
+ struct mm_struct *mm = p->mm;
+ struct mm_sched *pcpu_sched;
+ unsigned long epoch;
+
+ /*
+ * init_task and kthreads don't be having no mm
+ */
+ if (!mm || !mm->pcpu_sched)
+ return;
+
+ pcpu_sched = this_cpu_ptr(p->mm->pcpu_sched);
+
+ scoped_guard (raw_spinlock, &rq->cpu_epoch_lock) {
+ __update_mm_sched(rq, pcpu_sched);
+ pcpu_sched->runtime += delta_exec;
+ rq->cpu_runtime += delta_exec;
+ epoch = rq->cpu_epoch;
+ }
+
+ /*
+ * If this task hasn't hit task_cache_work() for a while, invalidate
+ * it's preferred state.
+ */
+ if (epoch - READ_ONCE(mm->mm_sched_epoch) > EPOCH_OLD) {
+ mm->mm_sched_cpu = -1;
+ pcpu_sched->occ = -1;
+ }
+}
+
+static void task_tick_cache(struct rq *rq, struct task_struct *p)
+{
+ struct callback_head *work = &p->cache_work;
+ struct mm_struct *mm = p->mm;
+
+ if (!mm || !mm->pcpu_sched)
+ return;
+
+ if (mm->mm_sched_epoch == rq->cpu_epoch)
+ return;
+
+ guard(raw_spinlock)(&mm->mm_sched_lock);
+
+ if (mm->mm_sched_epoch == rq->cpu_epoch)
+ return;
+
+ if (work->next == work) {
+ task_work_add(p, work, TWA_RESUME);
+ WRITE_ONCE(mm->mm_sched_epoch, rq->cpu_epoch);
+ }
+}
+
+static void task_cache_work(struct callback_head *work)
+{
+ struct task_struct *p = current;
+ struct mm_struct *mm = p->mm;
+ unsigned long m_a_occ = 0;
+ int cpu, m_a_cpu = -1;
+ cpumask_var_t cpus;
+
+ WARN_ON_ONCE(work != &p->cache_work);
+
+ work->next = work;
+
+ if (p->flags & PF_EXITING)
+ return;
+
+ if (!alloc_cpumask_var(&cpus, GFP_KERNEL))
+ return;
+
+ scoped_guard (cpus_read_lock) {
+ cpumask_copy(cpus, cpu_online_mask);
+
+ for_each_cpu(cpu, cpus) {
+ /* XXX sched_cluster_active */
+ struct sched_domain *sd = per_cpu(sd_llc, cpu);
+ unsigned long occ, m_occ = 0, a_occ = 0;
+ int m_cpu = -1, nr = 0, i;
+
+ for_each_cpu(i, sched_domain_span(sd)) {
+ occ = fraction_mm_sched(cpu_rq(i),
+ per_cpu_ptr(mm->pcpu_sched, i));
+ a_occ += occ;
+ if (occ > m_occ) {
+ m_occ = occ;
+ m_cpu = i;
+ }
+ nr++;
+ trace_printk("(%d) occ: %ld m_occ: %ld m_cpu: %d nr: %d\n",
+ per_cpu(sd_llc_id, i), occ, m_occ, m_cpu, nr);
+ }
+
+ a_occ /= nr;
+ if (a_occ > m_a_occ) {
+ m_a_occ = a_occ;
+ m_a_cpu = m_cpu;
+ }
+
+ trace_printk("(%d) a_occ: %ld m_a_occ: %ld\n",
+ per_cpu(sd_llc_id, cpu), a_occ, m_a_occ);
+
+ for_each_cpu(i, sched_domain_span(sd)) {
+ /* XXX threshold ? */
+ per_cpu_ptr(mm->pcpu_sched, i)->occ = a_occ;
+ }
+
+ cpumask_andnot(cpus, cpus, sched_domain_span(sd));
+ }
+ }
+
+ /*
+ * If the max average cache occupancy is 'small' we don't care.
+ */
+ if (m_a_occ < (NICE_0_LOAD >> EPOCH_OLD))
+ m_a_cpu = -1;
+
+ mm->mm_sched_cpu = m_a_cpu;
+
+ free_cpumask_var(cpus);
+}
+
+void init_sched_mm(struct task_struct *p)
+{
+ struct callback_head *work = &p->cache_work;
+ init_task_work(work, task_cache_work);
+ work->next = work;
+}
+
+#else
+
+static inline void account_mm_sched(struct rq *rq, struct task_struct *p,
+ s64 delta_exec) { }
+
+
+void init_sched_mm(struct task_struct *p) { }
+
+static void task_tick_cache(struct rq *rq, struct task_struct *p) { }
+
+#endif
+
+static inline
+void update_curr_task(struct rq *rq, struct task_struct *p, s64 delta_exec)
{
trace_sched_stat_runtime(p, delta_exec);
account_group_exec_runtime(p, delta_exec);
+ account_mm_sched(rq, p, delta_exec);
cgroup_account_cputime(p, delta_exec);
}

@@ -1215,7 +1434,7 @@ s64 update_curr_common(struct rq *rq)

delta_exec = update_curr_se(rq, &donor->se);
if (likely(delta_exec > 0))
- update_curr_task(donor, delta_exec);
+ update_curr_task(rq, donor, delta_exec);

return delta_exec;
}
@@ -1244,7 +1463,7 @@ static void update_curr(struct cfs_rq *cfs_rq)
if (entity_is_task(curr)) {
struct task_struct *p = task_of(curr);

- update_curr_task(p, delta_exec);
+ update_curr_task(rq, p, delta_exec);

/*
* If the fair_server is active, we need to account for the
@@ -7850,7 +8069,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
* per-cpu select_rq_mask usage
*/
lockdep_assert_irqs_disabled();
-
+again:
if ((available_idle_cpu(target) || sched_idle_cpu(target)) &&
asym_fits_cpu(task_util, util_min, util_max, target))
return target;
@@ -7888,7 +8107,8 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
/* Check a recently used CPU as a potential idle candidate: */
recent_used_cpu = p->recent_used_cpu;
p->recent_used_cpu = prev;
- if (recent_used_cpu != prev &&
+ if (prev == p->wake_cpu &&
+ recent_used_cpu != prev &&
recent_used_cpu != target &&
cpus_share_cache(recent_used_cpu, target) &&
(available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) &&
@@ -7941,6 +8161,18 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
if ((unsigned)i < nr_cpumask_bits)
return i;

+ if (prev != p->wake_cpu && !cpus_share_cache(prev, p->wake_cpu)) {
+ /*
+ * Most likely select_cache_cpu() will have re-directed
+ * the wakeup, but getting here means the preferred cache is
+ * too busy, so re-try with the actual previous.
+ *
+ * XXX wake_affine is lost for this pass.
+ */
+ prev = target = p->wake_cpu;
+ goto again;
+ }
+
/*
* For cluster machines which have lower sharing cache like L2 or
* LLC Tag, we tend to find an idle CPU in the target's cluster
@@ -8563,6 +8795,40 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
return target;
}

+#ifdef CONFIG_SCHED_CACHE
+static long __migrate_degrades_locality(struct task_struct *p, int src_cpu, int dst_cpu, bool idle);
+
+static int select_cache_cpu(struct task_struct *p, int prev_cpu)
+{
+ struct mm_struct *mm = p->mm;
+ int cpu;
+
+ if (!mm || p->nr_cpus_allowed == 1)
+ return prev_cpu;
+
+ cpu = mm->mm_sched_cpu;
+ if (cpu < 0)
+ return prev_cpu;
+
+
+ if (static_branch_likely(&sched_numa_balancing) &&
+ __migrate_degrades_locality(p, prev_cpu, cpu, false) > 0) {
+ /*
+ * XXX look for max occupancy inside prev_cpu's node
+ */
+ return prev_cpu;
+ }
+
+ return cpu;
+}
+#else
+static int select_cache_cpu(struct task_struct *p, int prev_cpu)
+{
+ return prev_cpu;
+}
+#endif
+
+
/*
* select_task_rq_fair: Select target runqueue for the waking task in domains
* that have the relevant SD flag set. In practice, this is SD_BALANCE_WAKE,
@@ -8588,6 +8854,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
* required for stable ->cpus_allowed
*/
lockdep_assert_held(&p->pi_lock);
+ guard(rcu)();
+
if (wake_flags & WF_TTWU) {
record_wakee(p);

@@ -8595,6 +8863,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
cpumask_test_cpu(cpu, p->cpus_ptr))
return cpu;

+ new_cpu = prev_cpu = select_cache_cpu(p, prev_cpu);
+
if (!is_rd_overutilized(this_rq()->rd)) {
new_cpu = find_energy_efficient_cpu(p, prev_cpu);
if (new_cpu >= 0)
@@ -8605,7 +8875,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, p->cpus_ptr);
}

- rcu_read_lock();
for_each_domain(cpu, tmp) {
/*
* If both 'cpu' and 'prev_cpu' are part of this domain,
@@ -8638,7 +8907,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
/* Fast path */
new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
}
- rcu_read_unlock();

return new_cpu;
}
@@ -9288,6 +9556,17 @@ static int task_hot(struct task_struct *p, struct lb_env *env)
if (sysctl_sched_migration_cost == 0)
return 0;

+#ifdef CONFIG_SCHED_CACHE
+ if (p->mm && p->mm->pcpu_sched) {
+ /*
+ * XXX things like Skylake have non-inclusive L3 and might not
+ * like this L3 centric view. What to do about L2 stickyness ?
+ */
+ return per_cpu_ptr(p->mm->pcpu_sched, env->src_cpu)->occ >
+ per_cpu_ptr(p->mm->pcpu_sched, env->dst_cpu)->occ;
+ }
+#endif
+
delta = rq_clock_task(env->src_rq) - p->se.exec_start;

return delta < (s64)sysctl_sched_migration_cost;
@@ -9299,27 +9578,25 @@ static int task_hot(struct task_struct *p, struct lb_env *env)
* Returns 0, if task migration is not affected by locality.
* Returns a negative value, if task migration improves locality i.e migration preferred.
*/
-static long migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
+static long __migrate_degrades_locality(struct task_struct *p, int src_cpu, int dst_cpu, bool idle)
{
struct numa_group *numa_group = rcu_dereference(p->numa_group);
unsigned long src_weight, dst_weight;
int src_nid, dst_nid, dist;

- if (!static_branch_likely(&sched_numa_balancing))
- return 0;
-
- if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
+ if (!p->numa_faults)
return 0;

- src_nid = cpu_to_node(env->src_cpu);
- dst_nid = cpu_to_node(env->dst_cpu);
+ src_nid = cpu_to_node(src_cpu);
+ dst_nid = cpu_to_node(dst_cpu);

if (src_nid == dst_nid)
return 0;

/* Migrating away from the preferred node is always bad. */
if (src_nid == p->numa_preferred_nid) {
- if (env->src_rq->nr_running > env->src_rq->nr_preferred_running)
+ struct rq *src_rq = cpu_rq(src_cpu);
+ if (src_rq->nr_running > src_rq->nr_preferred_running)
return 1;
else
return 0;
@@ -9330,7 +9607,7 @@ static long migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
return -1;

/* Leaving a core idle is often worse than degrading locality. */
- if (env->idle == CPU_IDLE)
+ if (idle)
return 0;

dist = node_distance(src_nid, dst_nid);
@@ -9345,7 +9622,24 @@ static long migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
return src_weight - dst_weight;
}

+static long migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
+{
+ if (!static_branch_likely(&sched_numa_balancing))
+ return 0;
+
+ if (!(env->sd->flags & SD_NUMA))
+ return 0;
+
+ return __migrate_degrades_locality(p, env->src_cpu, env->dst_cpu,
+ env->idle == CPU_IDLE);
+}
+
#else
+static long __migrate_degrades_locality(struct task_struct *p, int src_cpu, int dst_cpu, bool idle)
+{
+ return 0;
+}
+
static inline long migrate_degrades_locality(struct task_struct *p,
struct lb_env *env)
{
@@ -13104,8 +13398,8 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) {}
*/
static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
{
- struct cfs_rq *cfs_rq;
struct sched_entity *se = &curr->se;
+ struct cfs_rq *cfs_rq;

for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
@@ -13115,6 +13409,8 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
if (static_branch_unlikely(&sched_numa_balancing))
task_tick_numa(rq, curr);

+ task_tick_cache(rq, curr);
+
update_misfit_status(curr, rq);
check_update_overutilized_status(task_rq(curr));

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 47972f34ea70..d16ccd66ca07 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1171,6 +1171,12 @@ struct rq {
u64 clock_pelt_idle_copy;
u64 clock_idle_copy;
#endif
+#ifdef CONFIG_SCHED_CACHE
+ raw_spinlock_t cpu_epoch_lock;
+ u64 cpu_runtime;
+ unsigned long cpu_epoch;
+ unsigned long cpu_epoch_next;
+#endif

atomic_t nr_iowait;

@@ -3861,6 +3867,8 @@ static inline void task_tick_mm_cid(struct rq *rq, struct task_struct *curr) { }
static inline void init_sched_mm_cid(struct task_struct *t) { }
#endif /* !CONFIG_SCHED_MM_CID */

+extern void init_sched_mm(struct task_struct *p);
+
extern u64 avg_vruntime(struct cfs_rq *cfs_rq);
extern int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se);
#ifdef CONFIG_SMP