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Diffstat (limited to 'mm/swapfile.c')
-rw-r--r--mm/swapfile.c596
1 files changed, 464 insertions, 132 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 6cf2e60983b7..3963fc24fcc1 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -175,14 +175,296 @@ static void discard_swap_cluster(struct swap_info_struct *si,
}
}
-static int wait_for_discard(void *word)
+#define SWAPFILE_CLUSTER 256
+#define LATENCY_LIMIT 256
+
+static inline void cluster_set_flag(struct swap_cluster_info *info,
+ unsigned int flag)
{
- schedule();
- return 0;
+ info->flags = flag;
}
-#define SWAPFILE_CLUSTER 256
-#define LATENCY_LIMIT 256
+static inline unsigned int cluster_count(struct swap_cluster_info *info)
+{
+ return info->data;
+}
+
+static inline void cluster_set_count(struct swap_cluster_info *info,
+ unsigned int c)
+{
+ info->data = c;
+}
+
+static inline void cluster_set_count_flag(struct swap_cluster_info *info,
+ unsigned int c, unsigned int f)
+{
+ info->flags = f;
+ info->data = c;
+}
+
+static inline unsigned int cluster_next(struct swap_cluster_info *info)
+{
+ return info->data;
+}
+
+static inline void cluster_set_next(struct swap_cluster_info *info,
+ unsigned int n)
+{
+ info->data = n;
+}
+
+static inline void cluster_set_next_flag(struct swap_cluster_info *info,
+ unsigned int n, unsigned int f)
+{
+ info->flags = f;
+ info->data = n;
+}
+
+static inline bool cluster_is_free(struct swap_cluster_info *info)
+{
+ return info->flags & CLUSTER_FLAG_FREE;
+}
+
+static inline bool cluster_is_null(struct swap_cluster_info *info)
+{
+ return info->flags & CLUSTER_FLAG_NEXT_NULL;
+}
+
+static inline void cluster_set_null(struct swap_cluster_info *info)
+{
+ info->flags = CLUSTER_FLAG_NEXT_NULL;
+ info->data = 0;
+}
+
+/* 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)
+{
+ /*
+ * If scan_swap_map() can't find a free cluster, it will check
+ * si->swap_map directly. To make sure the discarding cluster isn't
+ * taken by scan_swap_map(), mark the swap entries bad (occupied). It
+ * will be cleared after discard
+ */
+ 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);
+ }
+
+ schedule_work(&si->discard_work);
+}
+
+/*
+ * Doing discard actually. After a cluster discard is finished, the cluster
+ * will be added to free cluster list. caller should hold si->lock.
+*/
+static void swap_do_scheduled_discard(struct swap_info_struct *si)
+{
+ struct swap_cluster_info *info;
+ unsigned int idx;
+
+ 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);
+ }
+ spin_unlock(&si->lock);
+
+ discard_swap_cluster(si, idx * SWAPFILE_CLUSTER,
+ SWAPFILE_CLUSTER);
+
+ 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);
+ }
+ memset(si->swap_map + idx * SWAPFILE_CLUSTER,
+ 0, SWAPFILE_CLUSTER);
+ }
+}
+
+static void swap_discard_work(struct work_struct *work)
+{
+ struct swap_info_struct *si;
+
+ si = container_of(work, struct swap_info_struct, discard_work);
+
+ spin_lock(&si->lock);
+ swap_do_scheduled_discard(si);
+ spin_unlock(&si->lock);
+}
+
+/*
+ * The cluster corresponding to page_nr will be used. The cluster will be
+ * removed from free cluster list and its usage counter will be increased.
+ */
+static void inc_cluster_info_page(struct swap_info_struct *p,
+ struct swap_cluster_info *cluster_info, unsigned long page_nr)
+{
+ unsigned long idx = page_nr / SWAPFILE_CLUSTER;
+
+ 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);
+ }
+ cluster_set_count_flag(&cluster_info[idx], 0, 0);
+ }
+
+ VM_BUG_ON(cluster_count(&cluster_info[idx]) >= SWAPFILE_CLUSTER);
+ cluster_set_count(&cluster_info[idx],
+ cluster_count(&cluster_info[idx]) + 1);
+}
+
+/*
+ * The cluster corresponding to page_nr decreases one usage. If the usage
+ * counter becomes 0, which means no page in the cluster is in using, we can
+ * optionally discard the cluster and add it to free cluster list.
+ */
+static void dec_cluster_info_page(struct swap_info_struct *p,
+ struct swap_cluster_info *cluster_info, unsigned long page_nr)
+{
+ unsigned long idx = page_nr / SWAPFILE_CLUSTER;
+
+ if (!cluster_info)
+ return;
+
+ VM_BUG_ON(cluster_count(&cluster_info[idx]) == 0);
+ cluster_set_count(&cluster_info[idx],
+ cluster_count(&cluster_info[idx]) - 1);
+
+ if (cluster_count(&cluster_info[idx]) == 0) {
+ /*
+ * If the swap is discardable, prepare discard the cluster
+ * instead of free it immediately. The cluster will be freed
+ * after discard.
+ */
+ if ((p->flags & (SWP_WRITEOK | SWP_PAGE_DISCARD)) ==
+ (SWP_WRITEOK | SWP_PAGE_DISCARD)) {
+ swap_cluster_schedule_discard(p, idx);
+ return;
+ }
+
+ 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);
+ }
+ }
+}
+
+/*
+ * It's possible scan_swap_map() uses a free cluster in the middle of free
+ * cluster list. Avoiding such abuse to avoid list corruption.
+ */
+static bool
+scan_swap_map_ssd_cluster_conflict(struct swap_info_struct *si,
+ unsigned long offset)
+{
+ struct percpu_cluster *percpu_cluster;
+ bool conflict;
+
+ offset /= SWAPFILE_CLUSTER;
+ conflict = !cluster_is_null(&si->free_cluster_head) &&
+ offset != cluster_next(&si->free_cluster_head) &&
+ cluster_is_free(&si->cluster_info[offset]);
+
+ if (!conflict)
+ return false;
+
+ percpu_cluster = this_cpu_ptr(si->percpu_cluster);
+ cluster_set_null(&percpu_cluster->index);
+ return true;
+}
+
+/*
+ * Try to get a swap entry from current cpu's swap entry pool (a cluster). This
+ * might involve allocating a new cluster for current CPU too.
+ */
+static void scan_swap_map_try_ssd_cluster(struct swap_info_struct *si,
+ unsigned long *offset, unsigned long *scan_base)
+{
+ struct percpu_cluster *cluster;
+ bool found_free;
+ unsigned long tmp;
+
+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;
+ cluster->next = cluster_next(&cluster->index) *
+ SWAPFILE_CLUSTER;
+ } else if (!cluster_is_null(&si->discard_cluster_head)) {
+ /*
+ * we don't have free cluster but have some clusters in
+ * discarding, do discard now and reclaim them
+ */
+ swap_do_scheduled_discard(si);
+ *scan_base = *offset = si->cluster_next;
+ goto new_cluster;
+ } else
+ return;
+ }
+
+ found_free = false;
+
+ /*
+ * Other CPUs can use our cluster if they can't find a free cluster,
+ * check if there is still free entry in the cluster
+ */
+ tmp = cluster->next;
+ while (tmp < si->max && tmp < (cluster_next(&cluster->index) + 1) *
+ SWAPFILE_CLUSTER) {
+ if (!si->swap_map[tmp]) {
+ found_free = true;
+ break;
+ }
+ tmp++;
+ }
+ if (!found_free) {
+ cluster_set_null(&cluster->index);
+ goto new_cluster;
+ }
+ cluster->next = tmp + 1;
+ *offset = tmp;
+ *scan_base = tmp;
+}
static unsigned long scan_swap_map(struct swap_info_struct *si,
unsigned char usage)
@@ -191,7 +473,6 @@ static unsigned long scan_swap_map(struct swap_info_struct *si,
unsigned long scan_base;
unsigned long last_in_cluster = 0;
int latency_ration = LATENCY_LIMIT;
- int found_free_cluster = 0;
/*
* We try to cluster swap pages by allocating them sequentially
@@ -207,24 +488,18 @@ static unsigned long scan_swap_map(struct swap_info_struct *si,
si->flags += SWP_SCANNING;
scan_base = offset = si->cluster_next;
+ /* SSD algorithm */
+ if (si->cluster_info) {
+ scan_swap_map_try_ssd_cluster(si, &offset, &scan_base);
+ goto checks;
+ }
+
if (unlikely(!si->cluster_nr--)) {
if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) {
si->cluster_nr = SWAPFILE_CLUSTER - 1;
goto checks;
}
- if (si->flags & SWP_PAGE_DISCARD) {
- /*
- * Start range check on racing allocations, in case
- * they overlap the cluster we eventually decide on
- * (we scan without swap_lock to allow preemption).
- * It's hardly conceivable that cluster_nr could be
- * wrapped during our scan, but don't depend on it.
- */
- if (si->lowest_alloc)
- goto checks;
- si->lowest_alloc = si->max;
- si->highest_alloc = 0;
- }
+
spin_unlock(&si->lock);
/*
@@ -248,7 +523,6 @@ static unsigned long scan_swap_map(struct swap_info_struct *si,
offset -= SWAPFILE_CLUSTER - 1;
si->cluster_next = offset;
si->cluster_nr = SWAPFILE_CLUSTER - 1;
- found_free_cluster = 1;
goto checks;
}
if (unlikely(--latency_ration < 0)) {
@@ -269,7 +543,6 @@ static unsigned long scan_swap_map(struct swap_info_struct *si,
offset -= SWAPFILE_CLUSTER - 1;
si->cluster_next = offset;
si->cluster_nr = SWAPFILE_CLUSTER - 1;
- found_free_cluster = 1;
goto checks;
}
if (unlikely(--latency_ration < 0)) {
@@ -281,10 +554,13 @@ static unsigned long scan_swap_map(struct swap_info_struct *si,
offset = scan_base;
spin_lock(&si->lock);
si->cluster_nr = SWAPFILE_CLUSTER - 1;
- si->lowest_alloc = 0;
}
checks:
+ if (si->cluster_info) {
+ while (scan_swap_map_ssd_cluster_conflict(si, offset))
+ scan_swap_map_try_ssd_cluster(si, &offset, &scan_base);
+ }
if (!(si->flags & SWP_WRITEOK))
goto no_page;
if (!si->highest_bit)
@@ -317,62 +593,10 @@ checks:
si->highest_bit = 0;
}
si->swap_map[offset] = usage;
+ inc_cluster_info_page(si, si->cluster_info, offset);
si->cluster_next = offset + 1;
si->flags -= SWP_SCANNING;
- if (si->lowest_alloc) {
- /*
- * Only set when SWP_PAGE_DISCARD, and there's a scan
- * for a free cluster in progress or just completed.
- */
- if (found_free_cluster) {
- /*
- * To optimize wear-levelling, discard the
- * old data of the cluster, taking care not to
- * discard any of its pages that have already
- * been allocated by racing tasks (offset has
- * already stepped over any at the beginning).
- */
- if (offset < si->highest_alloc &&
- si->lowest_alloc <= last_in_cluster)
- last_in_cluster = si->lowest_alloc - 1;
- si->flags |= SWP_DISCARDING;
- spin_unlock(&si->lock);
-
- if (offset < last_in_cluster)
- discard_swap_cluster(si, offset,
- last_in_cluster - offset + 1);
-
- spin_lock(&si->lock);
- si->lowest_alloc = 0;
- si->flags &= ~SWP_DISCARDING;
-
- smp_mb(); /* wake_up_bit advises this */
- wake_up_bit(&si->flags, ilog2(SWP_DISCARDING));
-
- } else if (si->flags & SWP_DISCARDING) {
- /*
- * Delay using pages allocated by racing tasks
- * until the whole discard has been issued. We
- * could defer that delay until swap_writepage,
- * but it's easier to keep this self-contained.
- */
- spin_unlock(&si->lock);
- wait_on_bit(&si->flags, ilog2(SWP_DISCARDING),
- wait_for_discard, TASK_UNINTERRUPTIBLE);
- spin_lock(&si->lock);
- } else {
- /*
- * Note pages allocated by racing tasks while
- * scan for a free cluster is in progress, so
- * that its final discard can exclude them.
- */
- if (offset < si->lowest_alloc)
- si->lowest_alloc = offset;
- if (offset > si->highest_alloc)
- si->highest_alloc = offset;
- }
- }
return offset;
scan:
@@ -527,16 +751,16 @@ static struct swap_info_struct *swap_info_get(swp_entry_t entry)
return p;
bad_free:
- printk(KERN_ERR "swap_free: %s%08lx\n", Unused_offset, entry.val);
+ pr_err("swap_free: %s%08lx\n", Unused_offset, entry.val);
goto out;
bad_offset:
- printk(KERN_ERR "swap_free: %s%08lx\n", Bad_offset, entry.val);
+ pr_err("swap_free: %s%08lx\n", Bad_offset, entry.val);
goto out;
bad_device:
- printk(KERN_ERR "swap_free: %s%08lx\n", Unused_file, entry.val);
+ pr_err("swap_free: %s%08lx\n", Unused_file, entry.val);
goto out;
bad_nofile:
- printk(KERN_ERR "swap_free: %s%08lx\n", Bad_file, entry.val);
+ pr_err("swap_free: %s%08lx\n", Bad_file, entry.val);
out:
return NULL;
}
@@ -600,6 +824,7 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
/* free if no reference */
if (!usage) {
+ dec_cluster_info_page(p, p->cluster_info, offset);
if (offset < p->lowest_bit)
p->lowest_bit = offset;
if (offset > p->highest_bit)
@@ -1107,7 +1332,7 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si,
else
continue;
}
- count = si->swap_map[i];
+ count = ACCESS_ONCE(si->swap_map[i]);
if (count && swap_count(count) != SWAP_MAP_BAD)
break;
}
@@ -1127,7 +1352,11 @@ int try_to_unuse(unsigned int type, bool frontswap,
{
struct swap_info_struct *si = swap_info[type];
struct mm_struct *start_mm;
- unsigned char *swap_map;
+ volatile unsigned char *swap_map; /* swap_map is accessed without
+ * locking. Mark it as volatile
+ * to prevent compiler doing
+ * something odd.
+ */
unsigned char swcount;
struct page *page;
swp_entry_t entry;
@@ -1178,7 +1407,15 @@ int try_to_unuse(unsigned int type, bool frontswap,
* reused since sys_swapoff() already disabled
* allocation from here, or alloc_page() failed.
*/
- if (!*swap_map)
+ swcount = *swap_map;
+ /*
+ * We don't hold lock here, so the swap entry could be
+ * SWAP_MAP_BAD (when the cluster is discarding).
+ * Instead of fail out, We can just skip the swap
+ * entry because swapoff will wait for discarding
+ * finish anyway.
+ */
+ if (!swcount || swcount == SWAP_MAP_BAD)
continue;
retval = -ENOMEM;
break;
@@ -1524,7 +1761,8 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
}
static void _enable_swap_info(struct swap_info_struct *p, int prio,
- unsigned char *swap_map)
+ unsigned char *swap_map,
+ struct swap_cluster_info *cluster_info)
{
int i, prev;
@@ -1533,6 +1771,7 @@ static void _enable_swap_info(struct swap_info_struct *p, int prio,
else
p->prio = --least_priority;
p->swap_map = swap_map;
+ p->cluster_info = cluster_info;
p->flags |= SWP_WRITEOK;
atomic_long_add(p->pages, &nr_swap_pages);
total_swap_pages += p->pages;
@@ -1553,12 +1792,13 @@ static void _enable_swap_info(struct swap_info_struct *p, int prio,
static void enable_swap_info(struct swap_info_struct *p, int prio,
unsigned char *swap_map,
+ struct swap_cluster_info *cluster_info,
unsigned long *frontswap_map)
{
frontswap_init(p->type, frontswap_map);
spin_lock(&swap_lock);
spin_lock(&p->lock);
- _enable_swap_info(p, prio, swap_map);
+ _enable_swap_info(p, prio, swap_map, cluster_info);
spin_unlock(&p->lock);
spin_unlock(&swap_lock);
}
@@ -1567,7 +1807,7 @@ static void reinsert_swap_info(struct swap_info_struct *p)
{
spin_lock(&swap_lock);
spin_lock(&p->lock);
- _enable_swap_info(p, p->prio, p->swap_map);
+ _enable_swap_info(p, p->prio, p->swap_map, p->cluster_info);
spin_unlock(&p->lock);
spin_unlock(&swap_lock);
}
@@ -1576,6 +1816,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
{
struct swap_info_struct *p = NULL;
unsigned char *swap_map;
+ struct swap_cluster_info *cluster_info;
unsigned long *frontswap_map;
struct file *swap_file, *victim;
struct address_space *mapping;
@@ -1651,6 +1892,8 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
goto out_dput;
}
+ flush_work(&p->discard_work);
+
destroy_swap_extents(p);
if (p->flags & SWP_CONTINUED)
free_swap_count_continuations(p);
@@ -1675,6 +1918,8 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
p->max = 0;
swap_map = p->swap_map;
p->swap_map = NULL;
+ cluster_info = p->cluster_info;
+ p->cluster_info = NULL;
p->flags = 0;
frontswap_map = frontswap_map_get(p);
frontswap_map_set(p, NULL);
@@ -1682,7 +1927,10 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
spin_unlock(&swap_lock);
frontswap_invalidate_area(type);
mutex_unlock(&swapon_mutex);
+ free_percpu(p->percpu_cluster);
+ p->percpu_cluster = NULL;
vfree(swap_map);
+ vfree(cluster_info);
vfree(frontswap_map);
/* Destroy swap account informatin */
swap_cgroup_swapoff(type);
@@ -1926,9 +2174,10 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
int i;
unsigned long maxpages;
unsigned long swapfilepages;
+ unsigned long last_page;
if (memcmp("SWAPSPACE2", swap_header->magic.magic, 10)) {
- printk(KERN_ERR "Unable to find swap-space signature\n");
+ pr_err("Unable to find swap-space signature\n");
return 0;
}
@@ -1942,9 +2191,8 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
}
/* Check the swap header's sub-version */
if (swap_header->info.version != 1) {
- printk(KERN_WARNING
- "Unable to handle swap header version %d\n",
- swap_header->info.version);
+ pr_warn("Unable to handle swap header version %d\n",
+ swap_header->info.version);
return 0;
}
@@ -1968,8 +2216,14 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
*/
maxpages = swp_offset(pte_to_swp_entry(
swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
- if (maxpages > swap_header->info.last_page) {
- maxpages = swap_header->info.last_page + 1;
+ last_page = swap_header->info.last_page;
+ if (last_page > maxpages) {
+ pr_warn("Truncating oversized swap area, only using %luk out of %luk\n",
+ maxpages << (PAGE_SHIFT - 10),
+ last_page << (PAGE_SHIFT - 10));
+ }
+ if (maxpages > last_page) {
+ maxpages = last_page + 1;
/* p->max is an unsigned int: don't overflow it */
if ((unsigned int)maxpages == 0)
maxpages = UINT_MAX;
@@ -1980,8 +2234,7 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
return 0;
swapfilepages = i_size_read(inode) >> PAGE_SHIFT;
if (swapfilepages && maxpages > swapfilepages) {
- printk(KERN_WARNING
- "Swap area shorter than signature indicates\n");
+ pr_warn("Swap area shorter than signature indicates\n");
return 0;
}
if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode))
@@ -1995,15 +2248,23 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
static int setup_swap_map_and_extents(struct swap_info_struct *p,
union swap_header *swap_header,
unsigned char *swap_map,
+ struct swap_cluster_info *cluster_info,
unsigned long maxpages,
sector_t *span)
{
int i;
unsigned int nr_good_pages;
int nr_extents;
+ unsigned long nr_clusters = DIV_ROUND_UP(maxpages, SWAPFILE_CLUSTER);
+ unsigned long idx = p->cluster_next / SWAPFILE_CLUSTER;
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);
+
for (i = 0; i < swap_header->info.nr_badpages; i++) {
unsigned int page_nr = swap_header->info.badpages[i];
if (page_nr == 0 || page_nr > swap_header->info.last_page)
@@ -2011,11 +2272,25 @@ static int setup_swap_map_and_extents(struct swap_info_struct *p,
if (page_nr < maxpages) {
swap_map[page_nr] = SWAP_MAP_BAD;
nr_good_pages--;
+ /*
+ * Haven't marked the cluster free yet, no list
+ * operation involved
+ */
+ inc_cluster_info_page(p, cluster_info, page_nr);
}
}
+ /* Haven't marked the cluster free yet, no list operation involved */
+ for (i = maxpages; i < round_up(maxpages, SWAPFILE_CLUSTER); i++)
+ inc_cluster_info_page(p, cluster_info, i);
+
if (nr_good_pages) {
swap_map[0] = SWAP_MAP_BAD;
+ /*
+ * Not mark the cluster free yet, no list
+ * operation involved
+ */
+ inc_cluster_info_page(p, cluster_info, 0);
p->max = maxpages;
p->pages = nr_good_pages;
nr_extents = setup_swap_extents(p, span);
@@ -2024,10 +2299,34 @@ static int setup_swap_map_and_extents(struct swap_info_struct *p,
nr_good_pages = p->pages;
}
if (!nr_good_pages) {
- printk(KERN_WARNING "Empty swap-file\n");
+ pr_warn("Empty swap-file\n");
return -EINVAL;
}
+ if (!cluster_info)
+ return nr_extents;
+
+ 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);
+ }
+ }
+ idx++;
+ if (idx == nr_clusters)
+ idx = 0;
+ }
return nr_extents;
}
@@ -2059,6 +2358,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
sector_t span;
unsigned long maxpages;
unsigned char *swap_map = NULL;
+ struct swap_cluster_info *cluster_info = NULL;
unsigned long *frontswap_map = NULL;
struct page *page = NULL;
struct inode *inode = NULL;
@@ -2073,6 +2373,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
if (IS_ERR(p))
return PTR_ERR(p);
+ INIT_WORK(&p->discard_work, swap_discard_work);
+
name = getname(specialfile);
if (IS_ERR(name)) {
error = PTR_ERR(name);
@@ -2132,13 +2434,38 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
error = -ENOMEM;
goto bad_swap;
}
+ if (p->bdev && blk_queue_nonrot(bdev_get_queue(p->bdev))) {
+ p->flags |= SWP_SOLIDSTATE;
+ /*
+ * select a random position to start with to help wear leveling
+ * SSD
+ */
+ p->cluster_next = 1 + (prandom_u32() % p->highest_bit);
+
+ cluster_info = vzalloc(DIV_ROUND_UP(maxpages,
+ SWAPFILE_CLUSTER) * sizeof(*cluster_info));
+ if (!cluster_info) {
+ error = -ENOMEM;
+ goto bad_swap;
+ }
+ p->percpu_cluster = alloc_percpu(struct percpu_cluster);
+ if (!p->percpu_cluster) {
+ error = -ENOMEM;
+ goto bad_swap;
+ }
+ for_each_possible_cpu(i) {
+ struct percpu_cluster *cluster;
+ cluster = per_cpu_ptr(p->percpu_cluster, i);
+ cluster_set_null(&cluster->index);
+ }
+ }
error = swap_cgroup_swapon(p->type, maxpages);
if (error)
goto bad_swap;
nr_extents = setup_swap_map_and_extents(p, swap_header, swap_map,
- maxpages, &span);
+ cluster_info, maxpages, &span);
if (unlikely(nr_extents < 0)) {
error = nr_extents;
goto bad_swap;
@@ -2147,41 +2474,33 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
if (frontswap_enabled)
frontswap_map = vzalloc(BITS_TO_LONGS(maxpages) * sizeof(long));
- if (p->bdev) {
- if (blk_queue_nonrot(bdev_get_queue(p->bdev))) {
- p->flags |= SWP_SOLIDSTATE;
- p->cluster_next = 1 + (prandom_u32() % p->highest_bit);
- }
-
- if ((swap_flags & SWAP_FLAG_DISCARD) && swap_discardable(p)) {
- /*
- * When discard is enabled for swap with no particular
- * policy flagged, we set all swap discard flags here in
- * order to sustain backward compatibility with older
- * swapon(8) releases.
- */
- p->flags |= (SWP_DISCARDABLE | SWP_AREA_DISCARD |
- SWP_PAGE_DISCARD);
+ if (p->bdev &&(swap_flags & SWAP_FLAG_DISCARD) && swap_discardable(p)) {
+ /*
+ * When discard is enabled for swap with no particular
+ * policy flagged, we set all swap discard flags here in
+ * order to sustain backward compatibility with older
+ * swapon(8) releases.
+ */
+ p->flags |= (SWP_DISCARDABLE | SWP_AREA_DISCARD |
+ SWP_PAGE_DISCARD);
- /*
- * By flagging sys_swapon, a sysadmin can tell us to
- * either do single-time area discards only, or to just
- * perform discards for released swap page-clusters.
- * Now it's time to adjust the p->flags accordingly.
- */
- if (swap_flags & SWAP_FLAG_DISCARD_ONCE)
- p->flags &= ~SWP_PAGE_DISCARD;
- else if (swap_flags & SWAP_FLAG_DISCARD_PAGES)
- p->flags &= ~SWP_AREA_DISCARD;
-
- /* issue a swapon-time discard if it's still required */
- if (p->flags & SWP_AREA_DISCARD) {
- int err = discard_swap(p);
- if (unlikely(err))
- printk(KERN_ERR
- "swapon: discard_swap(%p): %d\n",
- p, err);
- }
+ /*
+ * By flagging sys_swapon, a sysadmin can tell us to
+ * either do single-time area discards only, or to just
+ * perform discards for released swap page-clusters.
+ * Now it's time to adjust the p->flags accordingly.
+ */
+ if (swap_flags & SWAP_FLAG_DISCARD_ONCE)
+ p->flags &= ~SWP_PAGE_DISCARD;
+ else if (swap_flags & SWAP_FLAG_DISCARD_PAGES)
+ p->flags &= ~SWP_AREA_DISCARD;
+
+ /* issue a swapon-time discard if it's still required */
+ if (p->flags & SWP_AREA_DISCARD) {
+ int err = discard_swap(p);
+ if (unlikely(err))
+ pr_err("swapon: discard_swap(%p): %d\n",
+ p, err);
}
}
@@ -2190,9 +2509,9 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
if (swap_flags & SWAP_FLAG_PREFER)
prio =
(swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT;
- enable_swap_info(p, prio, swap_map, frontswap_map);
+ enable_swap_info(p, prio, swap_map, cluster_info, frontswap_map);
- printk(KERN_INFO "Adding %uk swap on %s. "
+ pr_info("Adding %uk swap on %s. "
"Priority:%d extents:%d across:%lluk %s%s%s%s%s\n",
p->pages<<(PAGE_SHIFT-10), name->name, p->prio,
nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10),
@@ -2211,6 +2530,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
error = 0;
goto out;
bad_swap:
+ free_percpu(p->percpu_cluster);
+ p->percpu_cluster = NULL;
if (inode && S_ISBLK(inode->i_mode) && p->bdev) {
set_blocksize(p->bdev, p->old_block_size);
blkdev_put(p->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
@@ -2222,6 +2543,7 @@ bad_swap:
p->flags = 0;
spin_unlock(&swap_lock);
vfree(swap_map);
+ vfree(cluster_info);
if (swap_file) {
if (inode && S_ISREG(inode->i_mode)) {
mutex_unlock(&inode->i_mutex);
@@ -2291,6 +2613,16 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
goto unlock_out;
count = p->swap_map[offset];
+
+ /*
+ * swapin_readahead() doesn't check if a swap entry is valid, so the
+ * swap entry could be SWAP_MAP_BAD. Check here with lock held.
+ */
+ if (unlikely(swap_count(count) == SWAP_MAP_BAD)) {
+ err = -ENOENT;
+ goto unlock_out;
+ }
+
has_cache = count & SWAP_HAS_CACHE;
count &= ~SWAP_HAS_CACHE;
err = 0;
@@ -2326,7 +2658,7 @@ out:
return err;
bad_file:
- printk(KERN_ERR "swap_dup: %s%08lx\n", Bad_file, entry.val);
+ pr_err("swap_dup: %s%08lx\n", Bad_file, entry.val);
goto out;
}