diff --git a/include/linux/mm.h b/include/linux/mm.h
index ce464cd4777eea900ec92f218675785cacd50d1d..81443d557a2e179a7d3768c63abc2519d9d1ed19 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -691,6 +691,12 @@ static inline bool cpupid_cpu_unset(int cpupid)
return cpupid_to_cpu(cpupid) == (-1 & LAST__CPU_MASK);
}
+static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid)
+{
+ return (task_pid & LAST__PID_MASK) == cpupid_to_pid(cpupid);
+}
+
+#define cpupid_match_pid(task, cpupid) __cpupid_match_pid(task->pid, cpupid)
#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
{
@@ -760,6 +766,11 @@ static inline bool cpupid_pid_unset(int cpupid)
static inline void page_cpupid_reset_last(struct page *page)
{
}
+
+static inline bool cpupid_match_pid(struct task_struct *task, int cpupid)
+{
+ return false;
+}
#endif /* CONFIG_NUMA_BALANCING */
static inline struct zone *page_zone(const struct page *page)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b6619792bb13348001094f55287713bf3025be45..f587ded5c148defea335e6406fa3545807a327f3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1347,6 +1347,9 @@ struct task_struct {
u64 node_stamp; /* migration stamp */
struct callback_head numa_work;
+ struct list_head numa_entry;
+ struct numa_group *numa_group;
+
/*
* Exponential decaying average of faults on a per-node basis.
* Scheduling placement decisions are made based on the these counts.
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1fe59da280e31501cb141a9eae2febee43f4e2a8..51092d5cc64c75980ea724e23c9cdeeb86acbc56 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1733,6 +1733,9 @@ static void __sched_fork(struct task_struct *p)
p->numa_work.next = &p->numa_work;
p->numa_faults = NULL;
p->numa_faults_buffer = NULL;
+
+ INIT_LIST_HEAD(&p->numa_entry);
+ p->numa_group = NULL;
#endif /* CONFIG_NUMA_BALANCING */
}
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index dbe0f628efa3c03963665cf32b86d07f9ecf4fd4..85565053a6ed2e626e532b59bbd678cd2dea91ed 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -888,6 +888,17 @@ static unsigned int task_scan_max(struct task_struct *p)
*/
unsigned int sysctl_numa_balancing_settle_count __read_mostly = 4;
+struct numa_group {
+ atomic_t refcount;
+
+ spinlock_t lock; /* nr_tasks, tasks */
+ int nr_tasks;
+ struct list_head task_list;
+
+ struct rcu_head rcu;
+ atomic_long_t faults[0];
+};
+
static inline int task_faults_idx(int nid, int priv)
{
return 2 * nid + priv;
@@ -1182,7 +1193,10 @@ static void task_numa_placement(struct task_struct *p)
int priv, i;
for (priv = 0; priv < 2; priv++) {
+ long diff;
+
i = task_faults_idx(nid, priv);
+ diff = -p->numa_faults[i];
/* Decay existing window, copy faults since last scan */
p->numa_faults[i] >>= 1;
@@ -1190,6 +1204,11 @@ static void task_numa_placement(struct task_struct *p)
p->numa_faults_buffer[i] = 0;
faults += p->numa_faults[i];
+ diff += p->numa_faults[i];
+ if (p->numa_group) {
+ /* safe because we can only change our own group */
+ atomic_long_add(diff, &p->numa_group->faults[i]);
+ }
}
if (faults > max_faults) {
@@ -1207,6 +1226,131 @@ static void task_numa_placement(struct task_struct *p)
}
}
+static inline int get_numa_group(struct numa_group *grp)
+{
+ return atomic_inc_not_zero(&grp->refcount);
+}
+
+static inline void put_numa_group(struct numa_group *grp)
+{
+ if (atomic_dec_and_test(&grp->refcount))
+ kfree_rcu(grp, rcu);
+}
+
+static void double_lock(spinlock_t *l1, spinlock_t *l2)
+{
+ if (l1 > l2)
+ swap(l1, l2);
+
+ spin_lock(l1);
+ spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
+}
+
+static void task_numa_group(struct task_struct *p, int cpupid)
+{
+ struct numa_group *grp, *my_grp;
+ struct task_struct *tsk;
+ bool join = false;
+ int cpu = cpupid_to_cpu(cpupid);
+ int i;
+
+ if (unlikely(!p->numa_group)) {
+ unsigned int size = sizeof(struct numa_group) +
+ 2*nr_node_ids*sizeof(atomic_long_t);
+
+ grp = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
+ if (!grp)
+ return;
+
+ atomic_set(&grp->refcount, 1);
+ spin_lock_init(&grp->lock);
+ INIT_LIST_HEAD(&grp->task_list);
+
+ for (i = 0; i < 2*nr_node_ids; i++)
+ atomic_long_set(&grp->faults[i], p->numa_faults[i]);
+
+ list_add(&p->numa_entry, &grp->task_list);
+ grp->nr_tasks++;
+ rcu_assign_pointer(p->numa_group, grp);
+ }
+
+ rcu_read_lock();
+ tsk = ACCESS_ONCE(cpu_rq(cpu)->curr);
+
+ if (!cpupid_match_pid(tsk, cpupid))
+ goto unlock;
+
+ grp = rcu_dereference(tsk->numa_group);
+ if (!grp)
+ goto unlock;
+
+ my_grp = p->numa_group;
+ if (grp == my_grp)
+ goto unlock;
+
+ /*
+ * Only join the other group if its bigger; if we're the bigger group,
+ * the other task will join us.
+ */
+ if (my_grp->nr_tasks > grp->nr_tasks)
+ goto unlock;
+
+ /*
+ * Tie-break on the grp address.
+ */
+ if (my_grp->nr_tasks == grp->nr_tasks && my_grp > grp)
+ goto unlock;
+
+ if (!get_numa_group(grp))
+ goto unlock;
+
+ join = true;
+
+unlock:
+ rcu_read_unlock();
+
+ if (!join)
+ return;
+
+ for (i = 0; i < 2*nr_node_ids; i++) {
+ atomic_long_sub(p->numa_faults[i], &my_grp->faults[i]);
+ atomic_long_add(p->numa_faults[i], &grp->faults[i]);
+ }
+
+ double_lock(&my_grp->lock, &grp->lock);
+
+ list_move(&p->numa_entry, &grp->task_list);
+ my_grp->nr_tasks--;
+ grp->nr_tasks++;
+
+ spin_unlock(&my_grp->lock);
+ spin_unlock(&grp->lock);
+
+ rcu_assign_pointer(p->numa_group, grp);
+
+ put_numa_group(my_grp);
+}
+
+void task_numa_free(struct task_struct *p)
+{
+ struct numa_group *grp = p->numa_group;
+ int i;
+
+ if (grp) {
+ for (i = 0; i < 2*nr_node_ids; i++)
+ atomic_long_sub(p->numa_faults[i], &grp->faults[i]);
+
+ spin_lock(&grp->lock);
+ list_del(&p->numa_entry);
+ grp->nr_tasks--;
+ spin_unlock(&grp->lock);
+ rcu_assign_pointer(p->numa_group, NULL);
+ put_numa_group(grp);
+ }
+
+ kfree(p->numa_faults);
+}
+
/*
* Got a PROT_NONE fault for a page on @node.
*/
@@ -1222,15 +1366,6 @@ void task_numa_fault(int last_cpupid, int node, int pages, bool migrated)
if (!p->mm)
return;
- /*
- * First accesses are treated as private, otherwise consider accesses
- * to be private if the accessing pid has not changed
- */
- if (!cpupid_pid_unset(last_cpupid))
- priv = ((p->pid & LAST__PID_MASK) == cpupid_to_pid(last_cpupid));
- else
- priv = 1;
-
/* Allocate buffer to track faults on a per-node basis */
if (unlikely(!p->numa_faults)) {
int size = sizeof(*p->numa_faults) * 2 * nr_node_ids;
@@ -1244,6 +1379,18 @@ void task_numa_fault(int last_cpupid, int node, int pages, bool migrated)
p->numa_faults_buffer = p->numa_faults + (2 * nr_node_ids);
}
+ /*
+ * First accesses are treated as private, otherwise consider accesses
+ * to be private if the accessing pid has not changed
+ */
+ if (unlikely(last_cpupid == (-1 & LAST_CPUPID_MASK))) {
+ priv = 1;
+ } else {
+ priv = cpupid_match_pid(p, last_cpupid);
+ if (!priv)
+ task_numa_group(p, last_cpupid);
+ }
+
/*
* If pages are properly placed (did not migrate) then scan slower.
* This is reset periodically in case of phase changes
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 691e96964dcccf1abfd9cbb1c4066442f5676d56..8037b10a256f2d1619fc3cfe3861197c8b52e128 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -559,10 +559,7 @@ static inline u64 rq_clock_task(struct rq *rq)
#ifdef CONFIG_NUMA_BALANCING
extern int migrate_task_to(struct task_struct *p, int cpu);
extern int migrate_swap(struct task_struct *, struct task_struct *);
-static inline void task_numa_free(struct task_struct *p)
-{
- kfree(p->numa_faults);
-}
+extern void task_numa_free(struct task_struct *p);
#else /* CONFIG_NUMA_BALANCING */
static inline void task_numa_free(struct task_struct *p)
{
diff --git a/mm/memory.c b/mm/memory.c
index 5162e6d0d6522eca38de500299cc676c1fbfeb2e..c57efa25cdbb235fa05d3a93222d5d72c9b0c387 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2719,6 +2719,14 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
get_page(dirty_page);
reuse:
+ /*
+ * Clear the pages cpupid information as the existing
+ * information potentially belongs to a now completely
+ * unrelated process.
+ */
+ if (old_page)
+ page_cpupid_xchg_last(old_page, (1 << LAST_CPUPID_SHIFT) - 1);
+
flush_cache_page(vma, address, pte_pfn(orig_pte));
entry = pte_mkyoung(orig_pte);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);