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tmpfs: shuffle add_to_swap_caches 

add_to_swap_cache doesn't amount to much: merge it into its sole caller
read_swap_cache_async.  But we'll be needing to call __add_to_swap_cache from
shmem.c, so promote it to the new add_to_swap_cache.  Both were static, so
there's no interface confusion to worry about.

And lose that inappropriate "Anon pages are already on the LRU" comment in the
merging: they're not already on the LRU, as Nick Piggin noticed.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
No-problems-with: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hugh Dickins 2008-02-04 22:28:49 -08:00 committed by Linus Torvalds
parent bb63be0a09
commit f000944d03
1 changed files with 19 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
mm/swap_state.c
View File

@ -64,10 +64,10 @@ void show_swap_cache_info(void)
} }
/* /*
* __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. * but sets SwapCache flag and private instead of mapping and index.
*/ */
static int __add_to_swap_cache(struct page *page, swp_entry_t entry, static int add_to_swap_cache(struct page *page, swp_entry_t entry,
gfp_t gfp_mask) gfp_t gfp_mask)
{ {
int error; int error;
@ -94,28 +94,6 @@ static int __add_to_swap_cache(struct page *page, swp_entry_t entry,
return error; return error;
} }
static int add_to_swap_cache(struct page *page, swp_entry_t entry,
gfp_t gfp_mask)
{
int error;
BUG_ON(PageLocked(page));
if (!swap_duplicate(entry))
return -ENOENT;
SetPageLocked(page);
error = __add_to_swap_cache(page, entry, gfp_mask & GFP_KERNEL);
/*
* Anon pages are already on the LRU, we don't run lru_cache_add here.
*/
if (error) {
ClearPageLocked(page);
swap_free(entry);
return error;
}
return 0;
}
/* /*
* This must be called only on pages that have * This must be called only on pages that have
* been verified to be in the swap cache. * been verified to be in the swap cache.
@ -165,7 +143,7 @@ int add_to_swap(struct page * page, gfp_t gfp_mask)
/* /*
* Add it to the swap cache and mark it dirty * 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); gfp_mask|__GFP_NOMEMALLOC|__GFP_NOWARN);
switch (err) { switch (err) {
@ -210,7 +188,7 @@ void delete_from_swap_cache(struct page *page)
*/ */
int move_to_swap_cache(struct page *page, swp_entry_t entry) int move_to_swap_cache(struct page *page, swp_entry_t entry)
{ {
int err = __add_to_swap_cache(page, entry, GFP_ATOMIC); int err = add_to_swap_cache(page, entry, GFP_ATOMIC);
if (!err) { if (!err) {
remove_from_page_cache(page); remove_from_page_cache(page);
page_cache_release(page); /* pagecache ref */ page_cache_release(page); /* pagecache ref */
@ -334,17 +312,22 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
break; /* Out of memory */ 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. * Associate the page with swap entry in the swap cache.
* May fail (-ENOENT) if swap entry has been freed since * May fail (-EEXIST) if there is already a page associated
* our caller observed it. May fail (-EEXIST) if there * with this entry in the swap cache: added by a racing
* is already a page associated with this entry in the * read_swap_cache_async, or add_to_swap or shmem_writepage
* swap cache: added by a racing read_swap_cache_async, * re-using the just freed swap entry for an existing page.
* or by try_to_swap_out (or shmem_writepage) re-using
* the just freed swap entry for an existing page.
* May fail (-ENOMEM) if radix-tree node allocation failed. * May fail (-ENOMEM) if radix-tree node allocation failed.
*/ */
err = add_to_swap_cache(new_page, entry, gfp_mask); SetPageLocked(new_page);
err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
if (!err) { if (!err) {
/* /*
* Initiate read into locked page and return. * Initiate read into locked page and return.
@ -353,7 +336,9 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
swap_readpage(NULL, new_page); swap_readpage(NULL, new_page);
return new_page; return new_page;
} }
} while (err != -ENOENT && err != -ENOMEM); ClearPageLocked(new_page);
swap_free(entry);
} while (err != -ENOMEM);
if (new_page) if (new_page)
page_cache_release(new_page); page_cache_release(new_page);