sched/numa, mm: make numa migrate functions to take a folio

The cpupid (or access time) is stored in the head page for THP, so it is
safely to make should_numa_migrate_memory() and numa_hint_fault_latency()
to take a folio. This is in preparation for large folio numa balancing.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Kefeng Wang <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: "Huang, Ying" <[e-mail]>
Cc: Hugh Dickins <[e-mail]>
Cc: Matthew Wilcox (Oracle) <[e-mail]>
Cc: Mike Kravetz <[e-mail]>
Cc: Zi Yan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/linux/sched/numa_balancing.h

···
 extern pid_t task_numa_group_id(struct task_struct *p);
 extern void set_numabalancing_state(bool enabled);
 extern void task_numa_free(struct task_struct *p, bool final);
-extern bool should_numa_migrate_memory(struct task_struct *p, struct page *page,
-					int src_nid, int dst_cpu);
+bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio,
+				int src_nid, int dst_cpu);
 #else
 static inline void task_numa_fault(int last_node, int node, int pages,
 				   int flags)
···
 {
 }
 static inline bool should_numa_migrate_memory(struct task_struct *p,
-				struct page *page, int src_nid, int dst_cpu)
+				struct folio *folio, int src_nid, int dst_cpu)
 {
 	return true;
 }

kernel/sched/fair.c

···
  * The smaller the hint page fault latency, the higher the possibility
  * for the page to be hot.
  */
-static int numa_hint_fault_latency(struct page *page)
+static int numa_hint_fault_latency(struct folio *folio)
 {
 	int last_time, time;
 
 	time = jiffies_to_msecs(jiffies);
-	last_time = xchg_page_access_time(page, time);
+	last_time = xchg_page_access_time(&folio->page, time);
 
 	return (time - last_time) & PAGE_ACCESS_TIME_MASK;
 }
···
 	}
 }
 
-bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
+bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio,
 				int src_nid, int dst_cpu)
 {
 	struct numa_group *ng = deref_curr_numa_group(p);
···
 		numa_promotion_adjust_threshold(pgdat, rate_limit, def_th);
 
 		th = pgdat->nbp_threshold ? : def_th;
-		latency = numa_hint_fault_latency(page);
+		latency = numa_hint_fault_latency(folio);
 		if (latency >= th)
 			return false;
 
 		return !numa_promotion_rate_limit(pgdat, rate_limit,
-						  thp_nr_pages(page));
+						  folio_nr_pages(folio));
 	}
 
 	this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid);
-	last_cpupid = page_cpupid_xchg_last(page, this_cpupid);
+	last_cpupid = page_cpupid_xchg_last(&folio->page, this_cpupid);
 
 	if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) &&
 	    !node_is_toptier(src_nid) && !cpupid_valid(last_cpupid))

mm/mempolicy.c

···
 	if (pol->flags & MPOL_F_MORON) {
 		polnid = thisnid;
 
-		if (!should_numa_migrate_memory(current, &folio->page, curnid,
+		if (!should_numa_migrate_memory(current, folio, curnid,
 						thiscpu))
 			goto out;
 	}