#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/module.h>
+#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/security.h>
#include <linux/backing-dev.h>
static bool swap_count_continued(struct swap_info_struct *, pgoff_t,
unsigned char);
static void free_swap_count_continuations(struct swap_info_struct *);
+static sector_t map_swap_entry(swp_entry_t, struct block_device**);
static DEFINE_SPINLOCK(swap_lock);
static unsigned int nr_swapfiles;
if (usage == SWAP_HAS_CACHE) {
VM_BUG_ON(!has_cache);
has_cache = 0;
+ } else if (count == SWAP_MAP_SHMEM) {
+ /*
+ * Or we could insist on shmem.c using a special
+ * swap_shmem_free() and free_shmem_swap_and_cache()...
+ */
+ count = 0;
} else if ((count & ~COUNT_CONTINUED) <= SWAP_MAP_MAX) {
if (count == COUNT_CONTINUED) {
if (swap_count_continued(p, offset, count))
int count;
VM_BUG_ON(!PageLocked(page));
+ if (unlikely(PageKsm(page)))
+ return 0;
count = page_mapcount(page);
if (count <= 1 && PageSwapCache(page)) {
count += page_swapcount(page);
SetPageDirty(page);
}
}
- return count == 1;
+ return count <= 1;
}
/*
return p != NULL;
}
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+/**
+ * mem_cgroup_count_swap_user - count the user of a swap entry
+ * @ent: the swap entry to be checked
+ * @pagep: the pointer for the swap cache page of the entry to be stored
+ *
+ * Returns the number of the user of the swap entry. The number is valid only
+ * for swaps of anonymous pages.
+ * If the entry is found on swap cache, the page is stored to pagep with
+ * refcount of it being incremented.
+ */
+int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep)
+{
+ struct page *page;
+ struct swap_info_struct *p;
+ int count = 0;
+
+ page = find_get_page(&swapper_space, ent.val);
+ if (page)
+ count += page_mapcount(page);
+ p = swap_info_get(ent);
+ if (p) {
+ count += swap_count(p->swap_map[swp_offset(ent)]);
+ spin_unlock(&swap_lock);
+ }
+
+ *pagep = page;
+ return count;
+}
+#endif
+
#ifdef CONFIG_HIBERNATION
/*
* Find the swap type that corresponds to given device (if any).
return 0;
if (!(swap_info[type]->flags & SWP_WRITEOK))
return 0;
- return map_swap_page(swp_entry(type, offset), &bdev);
+ return map_swap_entry(swp_entry(type, offset), &bdev);
}
/*
goto out;
}
- inc_mm_counter(vma->vm_mm, anon_rss);
+ dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
+ inc_mm_counter(vma->vm_mm, MM_ANONPAGES);
get_page(page);
set_pte_at(vma->vm_mm, addr, pte,
pte_mkold(mk_pte(page, vma->vm_page_prot)));
unsigned long addr, end, next;
int ret;
- if (page->mapping) {
+ if (page_anon_vma(page)) {
addr = page_address_in_vma(page, vma);
if (addr == -EFAULT)
return 0;
swp_entry_t entry;
unsigned int i = 0;
int retval = 0;
- int shmem;
/*
* When searching mms for an entry, a good strategy is to
/*
* Remove all references to entry.
- * Whenever we reach init_mm, there's no address space
- * to search, but use it as a reminder to search shmem.
*/
- shmem = 0;
swcount = *swap_map;
- if (swap_count(swcount)) {
- if (start_mm == &init_mm)
- shmem = shmem_unuse(entry, page);
- else
- retval = unuse_mm(start_mm, entry, page);
+ if (swap_count(swcount) == SWAP_MAP_SHMEM) {
+ retval = shmem_unuse(entry, page);
+ /* page has already been unlocked and released */
+ if (retval < 0)
+ break;
+ continue;
}
+ if (swap_count(swcount) && start_mm != &init_mm)
+ retval = unuse_mm(start_mm, entry, page);
+
if (swap_count(*swap_map)) {
int set_start_mm = (*swap_map >= swcount);
struct list_head *p = &start_mm->mmlist;
atomic_inc(&new_start_mm->mm_users);
atomic_inc(&prev_mm->mm_users);
spin_lock(&mmlist_lock);
- while (swap_count(*swap_map) && !retval && !shmem &&
+ while (swap_count(*swap_map) && !retval &&
(p = p->next) != &start_mm->mmlist) {
mm = list_entry(p, struct mm_struct, mmlist);
if (!atomic_inc_not_zero(&mm->mm_users))
swcount = *swap_map;
if (!swap_count(swcount)) /* any usage ? */
;
- else if (mm == &init_mm) {
+ else if (mm == &init_mm)
set_start_mm = 1;
- shmem = shmem_unuse(entry, page);
- } else
+ else
retval = unuse_mm(mm, entry, page);
if (set_start_mm && *swap_map < swcount) {
mmput(start_mm);
start_mm = new_start_mm;
}
- if (shmem) {
- /* page has already been unlocked and released */
- if (shmem > 0)
- continue;
- retval = shmem;
- break;
- }
if (retval) {
unlock_page(page);
page_cache_release(page);
* read from disk into another page. Splitting into two
* pages would be incorrect if swap supported "shared
* private" pages, but they are handled by tmpfs files.
+ *
+ * Given how unuse_vma() targets one particular offset
+ * in an anon_vma, once the anon_vma has been determined,
+ * this splitting happens to be just what is needed to
+ * handle where KSM pages have been swapped out: re-reading
+ * is unnecessarily slow, but we can fix that later on.
*/
if (swap_count(*swap_map) &&
PageDirty(page) && PageSwapCache(page)) {
/*
* Use this swapdev's extent info to locate the (PAGE_SIZE) block which
- * corresponds to page offset `offset'. Note that the type of this function
- * is sector_t, but it returns page offset into the bdev, not sector offset.
+ * corresponds to page offset for the specified swap entry.
+ * Note that the type of this function is sector_t, but it returns page offset
+ * into the bdev, not sector offset.
*/
-sector_t map_swap_page(swp_entry_t entry, struct block_device **bdev)
+static sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev)
{
struct swap_info_struct *sis;
struct swap_extent *start_se;
}
/*
+ * Returns the page offset into bdev for the specified page's swap entry.
+ */
+sector_t map_swap_page(struct page *page, struct block_device **bdev)
+{
+ swp_entry_t entry;
+ entry.val = page_private(page);
+ return map_swap_entry(entry, bdev);
+}
+
+/*
* Free all of a swapdev's extent information
*/
static void destroy_swap_extents(struct swap_info_struct *sis)
unsigned int type;
int i, prev;
int error;
- union swap_header *swap_header = NULL;
- unsigned int nr_good_pages = 0;
+ union swap_header *swap_header;
+ unsigned int nr_good_pages;
int nr_extents = 0;
sector_t span;
- unsigned long maxpages = 1;
+ unsigned long maxpages;
unsigned long swapfilepages;
unsigned char *swap_map = NULL;
struct page *page = NULL;
* swap pte.
*/
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;
+ swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
+ if (maxpages > swap_header->info.last_page) {
+ maxpages = swap_header->info.last_page + 1;
+ /* p->max is an unsigned int: don't overflow it */
+ if ((unsigned int)maxpages == 0)
+ maxpages = UINT_MAX;
+ }
p->highest_bit = maxpages - 1;
error = -EINVAL;
}
memset(swap_map, 0, maxpages);
+ nr_good_pages = maxpages - 1; /* omit header page */
+
for (i = 0; i < swap_header->info.nr_badpages; i++) {
- int page_nr = swap_header->info.badpages[i];
- if (page_nr <= 0 || page_nr >= swap_header->info.last_page) {
+ unsigned int page_nr = swap_header->info.badpages[i];
+ if (page_nr == 0 || page_nr > swap_header->info.last_page) {
error = -EINVAL;
goto bad_swap;
}
- swap_map[page_nr] = SWAP_MAP_BAD;
+ if (page_nr < maxpages) {
+ swap_map[page_nr] = SWAP_MAP_BAD;
+ nr_good_pages--;
+ }
}
error = swap_cgroup_swapon(type, maxpages);
if (error)
goto bad_swap;
- nr_good_pages = swap_header->info.last_page -
- swap_header->info.nr_badpages -
- 1 /* header page */;
-
if (nr_good_pages) {
swap_map[0] = SWAP_MAP_BAD;
p->max = maxpages;
}
/*
- * increase reference count of swap entry by 1.
+ * Help swapoff by noting that swap entry belongs to shmem/tmpfs
+ * (in which case its reference count is never incremented).
+ */
+void swap_shmem_alloc(swp_entry_t entry)
+{
+ __swap_duplicate(entry, SWAP_MAP_SHMEM);
+}
+
+/*
+ * Increase reference count of swap entry by 1.
+ * Returns 0 for success, or -ENOMEM if a swap_count_continuation is required
+ * but could not be atomically allocated. Returns 0, just as if it succeeded,
+ * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which
+ * might occur if a page table entry has got corrupted.
*/
int swap_duplicate(swp_entry_t entry)
{
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff