summaryrefslogtreecommitdiff
path: root/mm
diff options
context:
space:
mode:
Diffstat (limited to 'mm')
-rw-r--r--mm/swapfile.c235
1 files changed, 9 insertions, 226 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 574059158627..fca58d43b836 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1001,49 +1001,6 @@ static void swap_range_free(struct swap_info_struct *si, unsigned long offset,
WRITE_ONCE(si->inuse_pages, si->inuse_pages - nr_entries);
}
-static void set_cluster_next(struct swap_info_struct *si, unsigned long next)
-{
- unsigned long prev;
-
- if (!(si->flags & SWP_SOLIDSTATE)) {
- si->cluster_next = next;
- return;
- }
-
- prev = this_cpu_read(*si->cluster_next_cpu);
- /*
- * Cross the swap address space size aligned trunk, choose
- * another trunk randomly to avoid lock contention on swap
- * address space if possible.
- */
- if ((prev >> SWAP_ADDRESS_SPACE_SHIFT) !=
- (next >> SWAP_ADDRESS_SPACE_SHIFT)) {
- /* No free swap slots available */
- if (si->highest_bit <= si->lowest_bit)
- return;
- next = get_random_u32_inclusive(si->lowest_bit, si->highest_bit);
- next = ALIGN_DOWN(next, SWAP_ADDRESS_SPACE_PAGES);
- next = max_t(unsigned int, next, si->lowest_bit);
- }
- this_cpu_write(*si->cluster_next_cpu, next);
-}
-
-static bool swap_offset_available_and_locked(struct swap_info_struct *si,
- unsigned long offset)
-{
- if (data_race(!si->swap_map[offset])) {
- spin_lock(&si->lock);
- return true;
- }
-
- if (vm_swap_full() && READ_ONCE(si->swap_map[offset]) == SWAP_HAS_CACHE) {
- spin_lock(&si->lock);
- return true;
- }
-
- return false;
-}
-
static int cluster_alloc_swap(struct swap_info_struct *si,
unsigned char usage, int nr,
swp_entry_t slots[], int order)
@@ -1071,13 +1028,7 @@ static int scan_swap_map_slots(struct swap_info_struct *si,
unsigned char usage, int nr,
swp_entry_t slots[], int order)
{
- unsigned long offset;
- unsigned long scan_base;
- unsigned long last_in_cluster = 0;
- int latency_ration = LATENCY_LIMIT;
unsigned int nr_pages = 1 << order;
- int n_ret = 0;
- bool scanned_many = false;
/*
* We try to cluster swap pages by allocating them sequentially
@@ -1089,7 +1040,6 @@ static int scan_swap_map_slots(struct swap_info_struct *si,
* But we do now try to find an empty cluster. -Andrea
* And we let swap pages go all over an SSD partition. Hugh
*/
-
if (order > 0) {
/*
* Should not even be attempting large allocations when huge
@@ -1109,158 +1059,7 @@ static int scan_swap_map_slots(struct swap_info_struct *si,
return 0;
}
- if (si->cluster_info)
- return cluster_alloc_swap(si, usage, nr, slots, order);
-
- si->flags += SWP_SCANNING;
-
- /* For HDD, sequential access is more important. */
- scan_base = si->cluster_next;
- offset = scan_base;
-
- if (unlikely(!si->cluster_nr--)) {
- if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) {
- si->cluster_nr = SWAPFILE_CLUSTER - 1;
- goto checks;
- }
-
- spin_unlock(&si->lock);
-
- /*
- * If seek is expensive, start searching for new cluster from
- * start of partition, to minimize the span of allocated swap.
- */
- scan_base = offset = si->lowest_bit;
- last_in_cluster = offset + SWAPFILE_CLUSTER - 1;
-
- /* Locate the first empty (unaligned) cluster */
- for (; last_in_cluster <= READ_ONCE(si->highest_bit); offset++) {
- if (si->swap_map[offset])
- last_in_cluster = offset + SWAPFILE_CLUSTER;
- else if (offset == last_in_cluster) {
- spin_lock(&si->lock);
- offset -= SWAPFILE_CLUSTER - 1;
- si->cluster_next = offset;
- si->cluster_nr = SWAPFILE_CLUSTER - 1;
- goto checks;
- }
- if (unlikely(--latency_ration < 0)) {
- cond_resched();
- latency_ration = LATENCY_LIMIT;
- }
- }
-
- offset = scan_base;
- spin_lock(&si->lock);
- si->cluster_nr = SWAPFILE_CLUSTER - 1;
- }
-
-checks:
- if (!(si->flags & SWP_WRITEOK))
- goto no_page;
- if (!si->highest_bit)
- goto no_page;
- if (offset > si->highest_bit)
- scan_base = offset = si->lowest_bit;
-
- /* reuse swap entry of cache-only swap if not busy. */
- if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
- int swap_was_freed;
- spin_unlock(&si->lock);
- swap_was_freed = __try_to_reclaim_swap(si, offset, TTRS_ANYWAY | TTRS_DIRECT);
- spin_lock(&si->lock);
- /* entry was freed successfully, try to use this again */
- if (swap_was_freed > 0)
- goto checks;
- goto scan; /* check next one */
- }
-
- if (si->swap_map[offset]) {
- if (!n_ret)
- goto scan;
- else
- goto done;
- }
- memset(si->swap_map + offset, usage, nr_pages);
-
- swap_range_alloc(si, offset, nr_pages);
- slots[n_ret++] = swp_entry(si->type, offset);
-
- /* got enough slots or reach max slots? */
- if ((n_ret == nr) || (offset >= si->highest_bit))
- goto done;
-
- /* search for next available slot */
-
- /* time to take a break? */
- if (unlikely(--latency_ration < 0)) {
- if (n_ret)
- goto done;
- spin_unlock(&si->lock);
- cond_resched();
- spin_lock(&si->lock);
- latency_ration = LATENCY_LIMIT;
- }
-
- if (si->cluster_nr && !si->swap_map[++offset]) {
- /* non-ssd case, still more slots in cluster? */
- --si->cluster_nr;
- goto checks;
- }
-
- /*
- * Even if there's no free clusters available (fragmented),
- * try to scan a little more quickly with lock held unless we
- * have scanned too many slots already.
- */
- if (!scanned_many) {
- unsigned long scan_limit;
-
- if (offset < scan_base)
- scan_limit = scan_base;
- else
- scan_limit = si->highest_bit;
- for (; offset <= scan_limit && --latency_ration > 0;
- offset++) {
- if (!si->swap_map[offset])
- goto checks;
- }
- }
-
-done:
- if (order == 0)
- set_cluster_next(si, offset + 1);
- si->flags -= SWP_SCANNING;
- return n_ret;
-
-scan:
- VM_WARN_ON(order > 0);
- spin_unlock(&si->lock);
- while (++offset <= READ_ONCE(si->highest_bit)) {
- if (unlikely(--latency_ration < 0)) {
- cond_resched();
- latency_ration = LATENCY_LIMIT;
- scanned_many = true;
- }
- if (swap_offset_available_and_locked(si, offset))
- goto checks;
- }
- offset = si->lowest_bit;
- while (offset < scan_base) {
- if (unlikely(--latency_ration < 0)) {
- cond_resched();
- latency_ration = LATENCY_LIMIT;
- scanned_many = true;
- }
- if (swap_offset_available_and_locked(si, offset))
- goto checks;
- offset++;
- }
- spin_lock(&si->lock);
-
-no_page:
- si->flags -= SWP_SCANNING;
- return n_ret;
+ return cluster_alloc_swap(si, usage, nr, slots, order);
}
int get_swap_pages(int n_goal, swp_entry_t swp_entries[], int entry_order)
@@ -2871,8 +2670,6 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
mutex_unlock(&swapon_mutex);
free_percpu(p->percpu_cluster);
p->percpu_cluster = NULL;
- free_percpu(p->cluster_next_cpu);
- p->cluster_next_cpu = NULL;
vfree(swap_map);
kvfree(zeromap);
kvfree(cluster_info);
@@ -3184,8 +2981,6 @@ static unsigned long read_swap_header(struct swap_info_struct *si,
}
si->lowest_bit = 1;
- si->cluster_next = 1;
- si->cluster_nr = 0;
maxpages = swapfile_maximum_size;
last_page = swap_header->info.last_page;
@@ -3271,7 +3066,6 @@ static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
unsigned long maxpages)
{
unsigned long nr_clusters = DIV_ROUND_UP(maxpages, SWAPFILE_CLUSTER);
- unsigned long col = si->cluster_next / SWAPFILE_CLUSTER % SWAP_CLUSTER_COLS;
struct swap_cluster_info *cluster_info;
unsigned long i, j, k, idx;
int cpu, err = -ENOMEM;
@@ -3283,15 +3077,6 @@ static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
for (i = 0; i < nr_clusters; i++)
spin_lock_init(&cluster_info[i].lock);
- si->cluster_next_cpu = alloc_percpu(unsigned int);
- if (!si->cluster_next_cpu)
- goto err_free;
-
- /* Random start position to help with wear leveling */
- for_each_possible_cpu(cpu)
- per_cpu(*si->cluster_next_cpu, cpu) =
- get_random_u32_inclusive(1, si->highest_bit);
-
si->percpu_cluster = alloc_percpu(struct percpu_cluster);
if (!si->percpu_cluster)
goto err_free;
@@ -3333,7 +3118,7 @@ static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
* sharing same address space.
*/
for (k = 0; k < SWAP_CLUSTER_COLS; k++) {
- j = (k + col) % SWAP_CLUSTER_COLS;
+ j = k % SWAP_CLUSTER_COLS;
for (i = 0; i < DIV_ROUND_UP(nr_clusters, SWAP_CLUSTER_COLS); i++) {
struct swap_cluster_info *ci;
idx = i * SWAP_CLUSTER_COLS + j;
@@ -3483,18 +3268,18 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
if (si->bdev && bdev_nonrot(si->bdev)) {
si->flags |= SWP_SOLIDSTATE;
-
- cluster_info = setup_clusters(si, swap_header, maxpages);
- if (IS_ERR(cluster_info)) {
- error = PTR_ERR(cluster_info);
- cluster_info = NULL;
- goto bad_swap_unlock_inode;
- }
} else {
atomic_inc(&nr_rotate_swap);
inced_nr_rotate_swap = true;
}
+ cluster_info = setup_clusters(si, swap_header, maxpages);
+ if (IS_ERR(cluster_info)) {
+ error = PTR_ERR(cluster_info);
+ cluster_info = NULL;
+ goto bad_swap_unlock_inode;
+ }
+
if ((swap_flags & SWAP_FLAG_DISCARD) &&
si->bdev && bdev_max_discard_sectors(si->bdev)) {
/*
@@ -3575,8 +3360,6 @@ bad_swap_unlock_inode:
bad_swap:
free_percpu(si->percpu_cluster);
si->percpu_cluster = NULL;
- free_percpu(si->cluster_next_cpu);
- si->cluster_next_cpu = NULL;
inode = NULL;
destroy_swap_extents(si);
swap_cgroup_swapoff(si->type);
generated by cgit (git 2.34.1) at 2025-06-05 22:59:25 +0000