#include <asm/tlbflush.h>
#include <linux/swapops.h>
-DEFINE_SPINLOCK(swap_lock);
-unsigned int nr_swapfiles;
+static DEFINE_SPINLOCK(swap_lock);
+static unsigned int nr_swapfiles;
long total_swap_pages;
static int swap_overflow;
static int least_priority;
static const char Bad_offset[] = "Bad swap offset entry ";
static const char Unused_offset[] = "Unused swap offset entry ";
-struct swap_list_t swap_list = {-1, -1};
+static struct swap_list_t swap_list = {-1, -1};
static struct swap_info_struct swap_info[MAX_SWAPFILES];
* Work out if there are any other processes sharing this
* swap cache page. Free it if you can. Return success.
*/
-int remove_exclusive_swap_page(struct page *page)
+static int remove_exclusive_swap_page_count(struct page *page, int count)
{
int retval;
struct swap_info_struct * p;
return 0;
if (PageWriteback(page))
return 0;
- if (page_count(page) != 2) /* 2: us + cache */
+ if (page_count(page) != count) /* us + cache + ptes */
return 0;
entry.val = page_private(page);
retval = 0;
if (p->swap_map[swp_offset(entry)] == 1) {
/* Recheck the page count with the swapcache lock held.. */
- write_lock_irq(&swapper_space.tree_lock);
- if ((page_count(page) == 2) && !PageWriteback(page)) {
+ spin_lock_irq(&swapper_space.tree_lock);
+ if ((page_count(page) == count) && !PageWriteback(page)) {
__delete_from_swap_cache(page);
SetPageDirty(page);
retval = 1;
}
- write_unlock_irq(&swapper_space.tree_lock);
+ spin_unlock_irq(&swapper_space.tree_lock);
}
spin_unlock(&swap_lock);
return retval;
}
+/*
+ * Most of the time the page should have two references: one for the
+ * process and one for the swap cache.
+ */
+int remove_exclusive_swap_page(struct page *page)
+{
+ return remove_exclusive_swap_page_count(page, 2);
+}
+
+/*
+ * The pageout code holds an extra reference to the page. That raises
+ * the reference count to test for to 2 for a page that is only in the
+ * swap cache plus 1 for each process that maps the page.
+ */
+int remove_exclusive_swap_page_ref(struct page *page)
+{
+ return remove_exclusive_swap_page_count(page, 2 + page_mapcount(page));
+}
+
/*
* Free the swap entry like above, but also try to
* free the page cache entry if it is the last user.
if (p) {
if (swap_entry_free(p, swp_offset(entry)) == 1) {
page = find_get_page(&swapper_space, entry.val);
- if (page && unlikely(TestSetPageLocked(page))) {
+ if (page && !trylock_page(page)) {
page_cache_release(page);
page = NULL;
}
if (!down_read_trylock(&mm->mmap_sem)) {
/*
- * Activate page so shrink_cache is unlikely to unmap its
- * ptes while lock is dropped, so swapoff can make progress.
+ * Activate page so shrink_inactive_list is unlikely to unmap
+ * its ptes while lock is dropped, so swapoff can make progress.
*/
activate_page(page);
unlock_page(page);