#include <linux/mm.h>
#include <linux/kernel_stat.h>
#include <linux/swap.h>
+#include <linux/swapops.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
unsigned long del_total;
unsigned long find_success;
unsigned long find_total;
- unsigned long noent_race;
- unsigned long exist_race;
} swap_cache_info;
void show_swap_cache_info(void)
{
- printk("Swap cache: add %lu, delete %lu, find %lu/%lu, race %lu+%lu\n",
+ printk("Swap cache: add %lu, delete %lu, find %lu/%lu\n",
swap_cache_info.add_total, swap_cache_info.del_total,
- swap_cache_info.find_success, swap_cache_info.find_total,
- swap_cache_info.noent_race, swap_cache_info.exist_race);
+ swap_cache_info.find_success, swap_cache_info.find_total);
printk("Free swap = %lukB\n", nr_swap_pages << (PAGE_SHIFT - 10));
printk("Total swap = %lukB\n", total_swap_pages << (PAGE_SHIFT - 10));
}
/*
- * __add_to_swap_cache resembles add_to_page_cache on swapper_space,
+ * add_to_swap_cache resembles add_to_page_cache on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
-static int __add_to_swap_cache(struct page *page, swp_entry_t entry,
- gfp_t gfp_mask)
+int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
{
int error;
+ BUG_ON(!PageLocked(page));
BUG_ON(PageSwapCache(page));
BUG_ON(PagePrivate(page));
error = radix_tree_preload(gfp_mask);
entry.val, page);
if (!error) {
page_cache_get(page);
- SetPageLocked(page);
SetPageSwapCache(page);
set_page_private(page, entry.val);
total_swapcache_pages++;
__inc_zone_page_state(page, NR_FILE_PAGES);
+ INC_CACHE_INFO(add_total);
}
write_unlock_irq(&swapper_space.tree_lock);
radix_tree_preload_end();
return error;
}
-static int add_to_swap_cache(struct page *page, swp_entry_t entry)
-{
- int error;
-
- if (!swap_duplicate(entry)) {
- INC_CACHE_INFO(noent_race);
- return -ENOENT;
- }
- error = __add_to_swap_cache(page, entry, GFP_KERNEL);
- /*
- * Anon pages are already on the LRU, we don't run lru_cache_add here.
- */
- if (error) {
- swap_free(entry);
- if (error == -EEXIST)
- INC_CACHE_INFO(exist_race);
- return error;
- }
- INC_CACHE_INFO(add_total);
- return 0;
-}
-
/*
* This must be called only on pages that have
* been verified to be in the swap cache.
int err;
BUG_ON(!PageLocked(page));
+ BUG_ON(!PageUptodate(page));
for (;;) {
entry = get_swap_page();
/*
* Add it to the swap cache and mark it dirty
*/
- err = __add_to_swap_cache(page, entry,
+ err = add_to_swap_cache(page, entry,
gfp_mask|__GFP_NOMEMALLOC|__GFP_NOWARN);
switch (err) {
case 0: /* Success */
- SetPageUptodate(page);
SetPageDirty(page);
- INC_CACHE_INFO(add_total);
return 1;
case -EEXIST:
/* Raced with "speculative" read_swap_cache_async */
- INC_CACHE_INFO(exist_race);
swap_free(entry);
continue;
default:
page_cache_release(page);
}
-/*
- * Strange swizzling function only for use by shmem_writepage
- */
-int move_to_swap_cache(struct page *page, swp_entry_t entry)
-{
- int err = __add_to_swap_cache(page, entry, GFP_ATOMIC);
- if (!err) {
- remove_from_page_cache(page);
- page_cache_release(page); /* pagecache ref */
- if (!swap_duplicate(entry))
- BUG();
- SetPageDirty(page);
- INC_CACHE_INFO(add_total);
- } else if (err == -EEXIST)
- INC_CACHE_INFO(exist_race);
- return err;
-}
-
-/*
- * Strange swizzling function for shmem_getpage (and shmem_unuse)
- */
-int move_from_swap_cache(struct page *page, unsigned long index,
- struct address_space *mapping)
-{
- int err = add_to_page_cache(page, mapping, index, GFP_ATOMIC);
- if (!err) {
- delete_from_swap_cache(page);
- /* shift page from clean_pages to dirty_pages list */
- ClearPageDirty(page);
- set_page_dirty(page);
- }
- return err;
-}
-
/*
* If we are the only user, then try to free up the swap cache.
*
* A failure return means that either the page allocation failed or that
* the swap entry is no longer in use.
*/
-struct page *read_swap_cache_async(swp_entry_t entry,
+struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma, unsigned long addr)
{
struct page *found_page, *new_page = NULL;
* Get a new page to read into from swap.
*/
if (!new_page) {
- new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
- vma, addr);
+ new_page = alloc_page_vma(gfp_mask, vma, addr);
if (!new_page)
break; /* Out of memory */
}
+ /*
+ * Swap entry may have been freed since our caller observed it.
+ */
+ if (!swap_duplicate(entry))
+ break;
+
/*
* Associate the page with swap entry in the swap cache.
- * May fail (-ENOENT) if swap entry has been freed since
- * our caller observed it. May fail (-EEXIST) if there
- * is already a page associated with this entry in the
- * swap cache: added by a racing read_swap_cache_async,
- * or by try_to_swap_out (or shmem_writepage) re-using
- * the just freed swap entry for an existing page.
+ * May fail (-EEXIST) if there is already a page associated
+ * with this entry in the swap cache: added by a racing
+ * read_swap_cache_async, or add_to_swap or shmem_writepage
+ * re-using the just freed swap entry for an existing page.
* May fail (-ENOMEM) if radix-tree node allocation failed.
*/
- err = add_to_swap_cache(new_page, entry);
+ SetPageLocked(new_page);
+ err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
if (!err) {
/*
* Initiate read into locked page and return.
swap_readpage(NULL, new_page);
return new_page;
}
- } while (err != -ENOENT && err != -ENOMEM);
+ ClearPageLocked(new_page);
+ swap_free(entry);
+ } while (err != -ENOMEM);
if (new_page)
page_cache_release(new_page);
return found_page;
}
+
+/**
+ * swapin_readahead - swap in pages in hope we need them soon
+ * @entry: swap entry of this memory
+ * @vma: user vma this address belongs to
+ * @addr: target address for mempolicy
+ *
+ * Returns the struct page for entry and addr, after queueing swapin.
+ *
+ * Primitive swap readahead code. We simply read an aligned block of
+ * (1 << page_cluster) entries in the swap area. This method is chosen
+ * because it doesn't cost us any seek time. We also make sure to queue
+ * the 'original' request together with the readahead ones...
+ *
+ * This has been extended to use the NUMA policies from the mm triggering
+ * the readahead.
+ *
+ * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
+ */
+struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
+ struct vm_area_struct *vma, unsigned long addr)
+{
+ int nr_pages;
+ struct page *page;
+ unsigned long offset;
+ unsigned long end_offset;
+
+ /*
+ * Get starting offset for readaround, and number of pages to read.
+ * Adjust starting address by readbehind (for NUMA interleave case)?
+ * No, it's very unlikely that swap layout would follow vma layout,
+ * more likely that neighbouring swap pages came from the same node:
+ * so use the same "addr" to choose the same node for each swap read.
+ */
+ nr_pages = valid_swaphandles(entry, &offset);
+ for (end_offset = offset + nr_pages; offset < end_offset; offset++) {
+ /* Ok, do the async read-ahead now */
+ page = read_swap_cache_async(swp_entry(swp_type(entry), offset),
+ gfp_mask, vma, addr);
+ if (!page)
+ break;
+ page_cache_release(page);
+ }
+ lru_add_drain(); /* Push any new pages onto the LRU now */
+ return read_swap_cache_async(entry, gfp_mask, vma, addr);
+}
git.samba.org / sfrench / cifs-2.6.git / blobdiff