mm, swap: add swap_cluster_list
This is a code clean up patch without functionality changes. The
swap_cluster_list data structure and its operations are introduced to
provide some better encapsulation for the free cluster and discard
cluster list operations. This avoid some code duplication, improved the
code readability, and reduced the total line number.
[[email protected]: coding-style fixes]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: "Huang, Ying" <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Cc: Tim Chen <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Shaohua Li <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/include/linux/swap.h b/include/linux/swap.h
index e1d7614..a56523c 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -191,6 +191,11 @@
unsigned int next; /* Likely next allocation offset */
};
+struct swap_cluster_list {
+ struct swap_cluster_info head;
+ struct swap_cluster_info tail;
+};
+
/*
* The in-memory structure used to track swap areas.
*/
@@ -203,8 +208,7 @@
unsigned int max; /* extent of the swap_map */
unsigned char *swap_map; /* vmalloc'ed array of usage counts */
struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
- struct swap_cluster_info free_cluster_head; /* free cluster list head */
- struct swap_cluster_info free_cluster_tail; /* free cluster list tail */
+ struct swap_cluster_list free_clusters; /* free clusters list */
unsigned int lowest_bit; /* index of first free in swap_map */
unsigned int highest_bit; /* index of last free in swap_map */
unsigned int pages; /* total of usable pages of swap */
@@ -235,8 +239,7 @@
* first.
*/
struct work_struct discard_work; /* discard worker */
- struct swap_cluster_info discard_cluster_head; /* list head of discard clusters */
- struct swap_cluster_info discard_cluster_tail; /* list tail of discard clusters */
+ struct swap_cluster_list discard_clusters; /* discard clusters list */
};
/* linux/mm/workingset.c */
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 2657acc..134c085 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -257,6 +257,53 @@
info->data = 0;
}
+static inline bool cluster_list_empty(struct swap_cluster_list *list)
+{
+ return cluster_is_null(&list->head);
+}
+
+static inline unsigned int cluster_list_first(struct swap_cluster_list *list)
+{
+ return cluster_next(&list->head);
+}
+
+static void cluster_list_init(struct swap_cluster_list *list)
+{
+ cluster_set_null(&list->head);
+ cluster_set_null(&list->tail);
+}
+
+static void cluster_list_add_tail(struct swap_cluster_list *list,
+ struct swap_cluster_info *ci,
+ unsigned int idx)
+{
+ if (cluster_list_empty(list)) {
+ cluster_set_next_flag(&list->head, idx, 0);
+ cluster_set_next_flag(&list->tail, idx, 0);
+ } else {
+ unsigned int tail = cluster_next(&list->tail);
+
+ cluster_set_next(&ci[tail], idx);
+ cluster_set_next_flag(&list->tail, idx, 0);
+ }
+}
+
+static unsigned int cluster_list_del_first(struct swap_cluster_list *list,
+ struct swap_cluster_info *ci)
+{
+ unsigned int idx;
+
+ idx = cluster_next(&list->head);
+ if (cluster_next(&list->tail) == idx) {
+ cluster_set_null(&list->head);
+ cluster_set_null(&list->tail);
+ } else
+ cluster_set_next_flag(&list->head,
+ cluster_next(&ci[idx]), 0);
+
+ return idx;
+}
+
/* Add a cluster to discard list and schedule it to do discard */
static void swap_cluster_schedule_discard(struct swap_info_struct *si,
unsigned int idx)
@@ -270,17 +317,7 @@
memset(si->swap_map + idx * SWAPFILE_CLUSTER,
SWAP_MAP_BAD, SWAPFILE_CLUSTER);
- if (cluster_is_null(&si->discard_cluster_head)) {
- cluster_set_next_flag(&si->discard_cluster_head,
- idx, 0);
- cluster_set_next_flag(&si->discard_cluster_tail,
- idx, 0);
- } else {
- unsigned int tail = cluster_next(&si->discard_cluster_tail);
- cluster_set_next(&si->cluster_info[tail], idx);
- cluster_set_next_flag(&si->discard_cluster_tail,
- idx, 0);
- }
+ cluster_list_add_tail(&si->discard_clusters, si->cluster_info, idx);
schedule_work(&si->discard_work);
}
@@ -296,15 +333,8 @@
info = si->cluster_info;
- while (!cluster_is_null(&si->discard_cluster_head)) {
- idx = cluster_next(&si->discard_cluster_head);
-
- cluster_set_next_flag(&si->discard_cluster_head,
- cluster_next(&info[idx]), 0);
- if (cluster_next(&si->discard_cluster_tail) == idx) {
- cluster_set_null(&si->discard_cluster_head);
- cluster_set_null(&si->discard_cluster_tail);
- }
+ while (!cluster_list_empty(&si->discard_clusters)) {
+ idx = cluster_list_del_first(&si->discard_clusters, info);
spin_unlock(&si->lock);
discard_swap_cluster(si, idx * SWAPFILE_CLUSTER,
@@ -312,19 +342,7 @@
spin_lock(&si->lock);
cluster_set_flag(&info[idx], CLUSTER_FLAG_FREE);
- if (cluster_is_null(&si->free_cluster_head)) {
- cluster_set_next_flag(&si->free_cluster_head,
- idx, 0);
- cluster_set_next_flag(&si->free_cluster_tail,
- idx, 0);
- } else {
- unsigned int tail;
-
- tail = cluster_next(&si->free_cluster_tail);
- cluster_set_next(&info[tail], idx);
- cluster_set_next_flag(&si->free_cluster_tail,
- idx, 0);
- }
+ cluster_list_add_tail(&si->free_clusters, info, idx);
memset(si->swap_map + idx * SWAPFILE_CLUSTER,
0, SWAPFILE_CLUSTER);
}
@@ -353,13 +371,8 @@
if (!cluster_info)
return;
if (cluster_is_free(&cluster_info[idx])) {
- VM_BUG_ON(cluster_next(&p->free_cluster_head) != idx);
- cluster_set_next_flag(&p->free_cluster_head,
- cluster_next(&cluster_info[idx]), 0);
- if (cluster_next(&p->free_cluster_tail) == idx) {
- cluster_set_null(&p->free_cluster_tail);
- cluster_set_null(&p->free_cluster_head);
- }
+ VM_BUG_ON(cluster_list_first(&p->free_clusters) != idx);
+ cluster_list_del_first(&p->free_clusters, cluster_info);
cluster_set_count_flag(&cluster_info[idx], 0, 0);
}
@@ -398,14 +411,7 @@
}
cluster_set_flag(&cluster_info[idx], CLUSTER_FLAG_FREE);
- if (cluster_is_null(&p->free_cluster_head)) {
- cluster_set_next_flag(&p->free_cluster_head, idx, 0);
- cluster_set_next_flag(&p->free_cluster_tail, idx, 0);
- } else {
- unsigned int tail = cluster_next(&p->free_cluster_tail);
- cluster_set_next(&cluster_info[tail], idx);
- cluster_set_next_flag(&p->free_cluster_tail, idx, 0);
- }
+ cluster_list_add_tail(&p->free_clusters, cluster_info, idx);
}
}
@@ -421,8 +427,8 @@
bool conflict;
offset /= SWAPFILE_CLUSTER;
- conflict = !cluster_is_null(&si->free_cluster_head) &&
- offset != cluster_next(&si->free_cluster_head) &&
+ conflict = !cluster_list_empty(&si->free_clusters) &&
+ offset != cluster_list_first(&si->free_clusters) &&
cluster_is_free(&si->cluster_info[offset]);
if (!conflict)
@@ -447,11 +453,11 @@
new_cluster:
cluster = this_cpu_ptr(si->percpu_cluster);
if (cluster_is_null(&cluster->index)) {
- if (!cluster_is_null(&si->free_cluster_head)) {
- cluster->index = si->free_cluster_head;
+ if (!cluster_list_empty(&si->free_clusters)) {
+ cluster->index = si->free_clusters.head;
cluster->next = cluster_next(&cluster->index) *
SWAPFILE_CLUSTER;
- } else if (!cluster_is_null(&si->discard_cluster_head)) {
+ } else if (!cluster_list_empty(&si->discard_clusters)) {
/*
* we don't have free cluster but have some clusters in
* discarding, do discard now and reclaim them
@@ -2292,10 +2298,8 @@
nr_good_pages = maxpages - 1; /* omit header page */
- cluster_set_null(&p->free_cluster_head);
- cluster_set_null(&p->free_cluster_tail);
- cluster_set_null(&p->discard_cluster_head);
- cluster_set_null(&p->discard_cluster_tail);
+ cluster_list_init(&p->free_clusters);
+ cluster_list_init(&p->discard_clusters);
for (i = 0; i < swap_header->info.nr_badpages; i++) {
unsigned int page_nr = swap_header->info.badpages[i];
@@ -2341,19 +2345,8 @@
for (i = 0; i < nr_clusters; i++) {
if (!cluster_count(&cluster_info[idx])) {
cluster_set_flag(&cluster_info[idx], CLUSTER_FLAG_FREE);
- if (cluster_is_null(&p->free_cluster_head)) {
- cluster_set_next_flag(&p->free_cluster_head,
- idx, 0);
- cluster_set_next_flag(&p->free_cluster_tail,
- idx, 0);
- } else {
- unsigned int tail;
-
- tail = cluster_next(&p->free_cluster_tail);
- cluster_set_next(&cluster_info[tail], idx);
- cluster_set_next_flag(&p->free_cluster_tail,
- idx, 0);
- }
+ cluster_list_add_tail(&p->free_clusters, cluster_info,
+ idx);
}
idx++;
if (idx == nr_clusters)
