mm: Convert add_to_swap_cache to XArray (8d93b41c) · Commits · 戴 / test

mm/swap_state.c

+29 −64

Original line number	Diff line number	Diff line
		@@ -107,14 +107,15 @@ void show_swap_cache_info(void)
		}

		/*
		* __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
		* add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
		* but sets SwapCache flag and private instead of mapping and index.
		*/
		int __add_to_swap_cache(struct page *page, swp_entry_t entry)
		int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp)
		{
		int error, i, nr = hpage_nr_pages(page);
		struct address_space *address_space;
		struct address_space *address_space = swap_address_space(entry);
		pgoff_t idx = swp_offset(entry);
		XA_STATE_ORDER(xas, &address_space->i_pages, idx, compound_order(page));
		unsigned long i, nr = 1UL << compound_order(page);

		VM_BUG_ON_PAGE(!PageLocked(page), page);
		VM_BUG_ON_PAGE(PageSwapCache(page), page);
		@@ -123,50 +124,30 @@ int __add_to_swap_cache(struct page *page, swp_entry_t entry)
		page_ref_add(page, nr);
		SetPageSwapCache(page);

		address_space = swap_address_space(entry);
		xa_lock_irq(&address_space->i_pages);
		do {
		xas_lock_irq(&xas);
		xas_create_range(&xas);
		if (xas_error(&xas))
		goto unlock;
		for (i = 0; i < nr; i++) {
		VM_BUG_ON_PAGE(xas.xa_index != idx + i, page);
		set_page_private(page + i, entry.val + i);
		error = radix_tree_insert(&address_space->i_pages,
		idx + i, page + i);
		if (unlikely(error))
		break;
		xas_store(&xas, page + i);
		xas_next(&xas);
		}
		if (likely(!error)) {
		address_space->nrpages += nr;
		__mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr);
		ADD_CACHE_INFO(add_total, nr);
		} else {
		/*
		* Only the context which have set SWAP_HAS_CACHE flag
		* would call add_to_swap_cache().
		* So add_to_swap_cache() doesn't returns -EEXIST.
		*/
		VM_BUG_ON(error == -EEXIST);
		set_page_private(page + i, 0UL);
		while (i--) {
		radix_tree_delete(&address_space->i_pages, idx + i);
		set_page_private(page + i, 0UL);
		}
		ClearPageSwapCache(page);
		page_ref_sub(page, nr);
		}
		xa_unlock_irq(&address_space->i_pages);

		return error;
		}
		unlock:
		xas_unlock_irq(&xas);
		} while (xas_nomem(&xas, gfp));

		if (!xas_error(&xas))
		return 0;

		int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
		{
		int error;

		error = radix_tree_maybe_preload_order(gfp_mask, compound_order(page));
		if (!error) {
		error = __add_to_swap_cache(page, entry);
		radix_tree_preload_end();
		}
		return error;
		ClearPageSwapCache(page);
		page_ref_sub(page, nr);
		return xas_error(&xas);
		}

		/*
		@@ -217,7 +198,7 @@ int add_to_swap(struct page *page)
		return 0;

		/*
		* Radix-tree node allocations from PF_MEMALLOC contexts could
		* XArray node allocations from PF_MEMALLOC contexts could
		* completely exhaust the page allocator. __GFP_NOMEMALLOC
		* stops emergency reserves from being allocated.
		*
		@@ -229,7 +210,6 @@ int add_to_swap(struct page *page)
		*/
		err = add_to_swap_cache(page, entry,
		__GFP_HIGH\|__GFP_NOMEMALLOC\|__GFP_NOWARN);
		/* -ENOMEM radix-tree allocation failure */
		if (err)
		/*
		* add_to_swap_cache() doesn't return -EEXIST, so we can safely
		@@ -413,19 +393,11 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
		break; /* Out of memory */
		}

		/*
		* call radix_tree_preload() while we can wait.
		*/
		err = radix_tree_maybe_preload(gfp_mask & GFP_KERNEL);
		if (err)
		break;

		/*
		* Swap entry may have been freed since our caller observed it.
		*/
		err = swapcache_prepare(entry);
		if (err == -EEXIST) {
		radix_tree_preload_end();
		/*
		* We might race against get_swap_page() and stumble
		* across a SWAP_HAS_CACHE swap_map entry whose page
		@@ -433,26 +405,19 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
		*/
		cond_resched();
		continue;
		}
		if (err) { /* swp entry is obsolete ? */
		radix_tree_preload_end();
		} else if (err) /* swp entry is obsolete ? */
		break;
		}

		/* May fail (-ENOMEM) if radix-tree node allocation failed. */
		/* May fail (-ENOMEM) if XArray node allocation failed. */
		__SetPageLocked(new_page);
		__SetPageSwapBacked(new_page);
		err = __add_to_swap_cache(new_page, entry);
		err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
		if (likely(!err)) {
		radix_tree_preload_end();
		/*
		* Initiate read into locked page and return.
		*/
		/* Initiate read into locked page */
		lru_cache_add_anon(new_page);
		*new_page_allocated = true;
		return new_page;
		}
		radix_tree_preload_end();
		__ClearPageLocked(new_page);
		/*
		* add_to_swap_cache() doesn't return -EEXIST, so we can safely

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