Re: [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix

Andrea Arcangeli
2004-03-31T15:26:43Z

On Wed, Mar 31, 2004 at 05:07:18PM +0200, Andrea Arcangeli wrote:
> diff -urNp --exclude CVS --exclude BitKeeper --exclude {arch} --exclude .arch-ids x-ref/mm/page_io.c x/mm/page_io.c
> --- x-ref/mm/page_io.c 2004-03-31 16:57:25.505978008 +0200
> +++ x/mm/page_io.c 2004-03-31 17:06:07.028694504 +0200
> @@ -139,7 +139,7 @@ struct address_space_operations swap_aop
>
> /*
> * A scruffy utility function to read or write an arbitrary swap page
> - * and wait on the I/O.
> + * and wait on the I/O. The caller must have a ref on the page.
> */
> int rw_swap_page_sync(int rw, swp_entry_t entry, struct page *page)
> {
> @@ -149,10 +149,9 @@ int rw_swap_page_sync(int rw, swp_entry_
> };
>
> lock_page(page);
> -
> - BUG_ON(page->mapping);
> - page->mapping = &swapper_space;
> - page->index = entry.val;
> + ret = add_to_swap_cache(page, entry);
> + if (unlikely(ret))
> + goto out_unlock;
>
> if (rw == READ) {
> ret = swap_readpage(NULL, page);
> @@ -161,7 +160,12 @@ int rw_swap_page_sync(int rw, swp_entry_
> ret = swap_writepage(page, &swap_wbc);
> wait_on_page_writeback(page);
> }
> - page->mapping = NULL;
> +
> + lock_page(page);
> + delete_from_swap_cache(page);
> + out_unlock:
> + unlock_page(page);
> +
> if (ret == 0 && (!PageUptodate(page) || PageError(page)))
> ret = -EIO;
> return ret;
>
>

this trivial bit is needed as well to allow compilation, you can append
it to the previous patch:

--- x/include/linux/swap.h.~1~ 2004-03-31 17:13:05.064143456 +0200
+++ x/include/linux/swap.h 2004-03-31 17:21:34.241736696 +0200
@@ -192,6 +192,7 @@ extern struct address_space swapper_spac
#define total_swapcache_pages swapper_space.nrpages
extern void show_swap_cache_info(void);
extern int add_to_swap(struct page *);
+extern int add_to_swap_cache(struct page *page, swp_entry_t entry);
extern void __delete_from_swap_cache(struct page *);
extern void delete_from_swap_cache(struct page *);
extern int move_to_swap_cache(struct page *, swp_entry_t);
--- x/mm/swap_state.c.~1~ 2004-03-31 17:13:05.249115336 +0200
+++ x/mm/swap_state.c 2004-03-31 17:21:15.201631232 +0200
@@ -56,7 +56,7 @@ void show_swap_cache_info(void)
swap_cache_info.noent_race, swap_cache_info.exist_race);
}

-static int add_to_swap_cache(struct page *page, swp_entry_t entry)
+int add_to_swap_cache(struct page *page, swp_entry_t entry)
{
int error;