sched/numa: Rename vma_numab_state::access_pids[] => ::pids_active[], ::next_pid_reset => ::pids_active_reset

The access_pids[] field name is somewhat ambiguous as no PIDs are accessed.
Similarly, it's not clear that next_pid_reset is related to access_pids[].
Rename the fields to more accurately reflect their purpose.

[ mingo: Rename in the comments too. ]

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231010083143.19593-3-mgorman@techsingularity.net

Author: gormanm

include/linux/mm.h

@@ -1726,8 +1726,8 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
 	unsigned int pid_bit;
 
 	pid_bit = hash_32(current->pid, ilog2(BITS_PER_LONG));
-	if (vma->numab_state && !test_bit(pid_bit, &vma->numab_state->access_pids[1])) {
-		__set_bit(pid_bit, &vma->numab_state->access_pids[1]);
+	if (vma->numab_state && !test_bit(pid_bit, &vma->numab_state->pids_active[1])) {
+		__set_bit(pid_bit, &vma->numab_state->pids_active[1]);
 	}
 }
 #else /* !CONFIG_NUMA_BALANCING */

include/linux/mm_types.h

@@ -559,10 +559,10 @@ struct vma_numab_state {
 	unsigned long next_scan;
 
 	/*
-	 * Time in jiffies when access_pids[] is reset to
+	 * Time in jiffies when pids_active[] is reset to
 	 * detect phase change behaviour:
 	 */
-	unsigned long next_pid_reset;
+	unsigned long pids_active_reset;
 
 	/*
 	 * Approximate tracking of PIDs that trapped a NUMA hinting
@@ -574,7 +574,7 @@ struct vma_numab_state {
 	 * Window moves after next_pid_reset has expired approximately
 	 * every VMA_PID_RESET_PERIOD jiffies:
 	 */
-	unsigned long access_pids[2];
+	unsigned long pids_active[2];
 };
 
 /*

kernel/sched/fair.c

@@ -3125,7 +3125,7 @@ static bool vma_is_accessed(struct vm_area_struct *vma)
 	if (READ_ONCE(current->mm->numa_scan_seq) < 2)
 		return true;
 
-	pids = vma->numab_state->access_pids[0] | vma->numab_state->access_pids[1];
+	pids = vma->numab_state->pids_active[0] | vma->numab_state->pids_active[1];
 	return test_bit(hash_32(current->pid, ilog2(BITS_PER_LONG)), &pids);
 }
 
@@ -3241,7 +3241,7 @@ static void task_numa_work(struct callback_head *work)
 				msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
 
 			/* Reset happens after 4 times scan delay of scan start */
-			vma->numab_state->next_pid_reset =  vma->numab_state->next_scan +
+			vma->numab_state->pids_active_reset =  vma->numab_state->next_scan +
 				msecs_to_jiffies(VMA_PID_RESET_PERIOD);
 		}
 
@@ -3262,11 +3262,11 @@ static void task_numa_work(struct callback_head *work)
 		 * vma for recent access to avoid clearing PID info before access..
 		 */
 		if (mm->numa_scan_seq &&
-				time_after(jiffies, vma->numab_state->next_pid_reset)) {
-			vma->numab_state->next_pid_reset = vma->numab_state->next_pid_reset +
+				time_after(jiffies, vma->numab_state->pids_active_reset)) {
+			vma->numab_state->pids_active_reset = vma->numab_state->pids_active_reset +
 				msecs_to_jiffies(VMA_PID_RESET_PERIOD);
-			vma->numab_state->access_pids[0] = READ_ONCE(vma->numab_state->access_pids[1]);
-			vma->numab_state->access_pids[1] = 0;
+			vma->numab_state->pids_active[0] = READ_ONCE(vma->numab_state->pids_active[1]);
+			vma->numab_state->pids_active[1] = 0;
 		}
 
 		do {