Commit e21a2955 authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

shmem: Convert find_swap_entry to XArray 



This is a 1:1 conversion.  The major part of this patch is converting
the test framework from userspace to kernel space and mirroring the
algorithm now used in find_swap_entry().

Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
parent a12831bf

lib/test_xarray.c

+56 −0
Original line number Diff line number Diff line
@@ -631,6 +631,61 @@ static noinline void check_find(struct xarray *xa) 
	check_multi_find_2(xa);

}



/* See find_swap_entry() in mm/shmem.c */

static noinline unsigned long xa_find_entry(struct xarray *xa, void *item)

{

	XA_STATE(xas, xa, 0);

	unsigned int checked = 0;

	void *entry;



	rcu_read_lock();

	xas_for_each(&xas, entry, ULONG_MAX) {

		if (xas_retry(&xas, entry))

			continue;

		if (entry == item)

			break;

		checked++;

		if ((checked % 4) != 0)

			continue;

		xas_pause(&xas);

	}

	rcu_read_unlock();



	return entry ? xas.xa_index : -1;

}



static noinline void check_find_entry(struct xarray *xa)

{

#ifdef CONFIG_XARRAY_MULTI

	unsigned int order;

	unsigned long offset, index;



	for (order = 0; order < 20; order++) {

		for (offset = 0; offset < (1UL << (order + 3));

		     offset += (1UL << order)) {

			for (index = 0; index < (1UL << (order + 5));

			     index += (1UL << order)) {

				xa_store_order(xa, index, order,

						xa_mk_value(index), GFP_KERNEL);

				XA_BUG_ON(xa, xa_load(xa, index) !=

						xa_mk_value(index));

				XA_BUG_ON(xa, xa_find_entry(xa,

						xa_mk_value(index)) != index);

			}

			XA_BUG_ON(xa, xa_find_entry(xa, xa) != -1);

			xa_destroy(xa);

		}

	}

#endif



	XA_BUG_ON(xa, xa_find_entry(xa, xa) != -1);

	xa_store_index(xa, ULONG_MAX, GFP_KERNEL);

	XA_BUG_ON(xa, xa_find_entry(xa, xa) != -1);

	XA_BUG_ON(xa, xa_find_entry(xa, xa_mk_value(LONG_MAX)) != -1);

	xa_erase_index(xa, ULONG_MAX);

	XA_BUG_ON(xa, !xa_empty(xa));

}



static noinline void check_move_small(struct xarray *xa, unsigned long idx)

{

	XA_STATE(xas, xa, 0);
@@ -972,6 +1027,7 @@ static int xarray_checks(void) 
	check_multi_store(&array);

	check_xa_alloc();

	check_find(&array);

	check_find_entry(&array);

	check_destroy(&array);

	check_move(&array);

	check_create_range(&array);

mm/shmem.c

+10 −17
Original line number Diff line number Diff line
@@ -1100,34 +1100,27 @@ static void shmem_evict_inode(struct inode *inode) 
	clear_inode(inode);

}



static unsigned long find_swap_entry(struct radix_tree_root *root, void *item)

static unsigned long find_swap_entry(struct xarray *xa, void *item)

{

	struct radix_tree_iter iter;

	void __rcu **slot;

	unsigned long found = -1;

	XA_STATE(xas, xa, 0);

	unsigned int checked = 0;

	void *entry;



	rcu_read_lock();

	radix_tree_for_each_slot(slot, root, &iter, 0) {

		void *entry = radix_tree_deref_slot(slot);



		if (radix_tree_deref_retry(entry)) {

			slot = radix_tree_iter_retry(&iter);

	xas_for_each(&xas, entry, ULONG_MAX) {

		if (xas_retry(&xas, entry))

			continue;

		}

		if (entry == item) {

			found = iter.index;

		if (entry == item)

			break;

		}

		checked++;

		if ((checked % 4096) != 0)

		if ((checked % XA_CHECK_SCHED) != 0)

			continue;

		slot = radix_tree_iter_resume(slot, &iter);

		xas_pause(&xas);

		cond_resched_rcu();

	}



	rcu_read_unlock();

	return found;



	return entry ? xas.xa_index : -1;

}



/*

tools/testing/radix-tree/main.c

+0 −61
Original line number Diff line number Diff line
@@ -236,63 +236,6 @@ void copy_tag_check(void) 
	item_kill_tree(&tree);

}



static void __locate_check(struct radix_tree_root *tree, unsigned long index,

			unsigned order)

{

	struct item *item;

	unsigned long index2;



	item_insert_order(tree, index, order);

	item = item_lookup(tree, index);

	index2 = find_item(tree, item);

	if (index != index2) {

		printv(2, "index %ld order %d inserted; found %ld\n",

			index, order, index2);

		abort();

	}

}



static void __order_0_locate_check(void)

{

	RADIX_TREE(tree, GFP_KERNEL);

	int i;



	for (i = 0; i < 50; i++)

		__locate_check(&tree, rand() % INT_MAX, 0);



	item_kill_tree(&tree);

}



static void locate_check(void)

{

	RADIX_TREE(tree, GFP_KERNEL);

	unsigned order;

	unsigned long offset, index;



	__order_0_locate_check();



	for (order = 0; order < 20; order++) {

		for (offset = 0; offset < (1 << (order + 3));

		     offset += (1UL << order)) {

			for (index = 0; index < (1UL << (order + 5));

			     index += (1UL << order)) {

				__locate_check(&tree, index + offset, order);

			}

			if (find_item(&tree, &tree) != -1)

				abort();



			item_kill_tree(&tree);

		}

	}



	if (find_item(&tree, &tree) != -1)

		abort();

	__locate_check(&tree, -1, 0);

	if (find_item(&tree, &tree) != -1)

		abort();

	item_kill_tree(&tree);

}



static void single_thread_tests(bool long_run)

{

	int i;
@@ -303,10 +246,6 @@ static void single_thread_tests(bool long_run) 
	rcu_barrier();

	printv(2, "after multiorder_check: %d allocated, preempt %d\n",

		nr_allocated, preempt_count);

	locate_check();

	rcu_barrier();

	printv(2, "after locate_check: %d allocated, preempt %d\n",

		nr_allocated, preempt_count);

	tag_check();

	rcu_barrier();

	printv(2, "after tag_check: %d allocated, preempt %d\n",

tools/testing/radix-tree/test.c

+0 −22
Original line number Diff line number Diff line
@@ -209,28 +209,6 @@ int tag_tagged_items(struct radix_tree_root *root, pthread_mutex_t *lock, 
	return tagged;

}



/* Use the same pattern as find_swap_entry() in mm/shmem.c */

unsigned long find_item(struct radix_tree_root *root, void *item)

{

	struct radix_tree_iter iter;

	void **slot;

	unsigned long found = -1;

	unsigned long checked = 0;



	radix_tree_for_each_slot(slot, root, &iter, 0) {

		if (*slot == item) {

			found = iter.index;

			break;

		}

		checked++;

		if ((checked % 4) != 0)

			continue;

		slot = radix_tree_iter_resume(slot, &iter);

	}



	return found;

}



static int verify_node(struct radix_tree_node *slot, unsigned int tag,

			int tagged)

{

tools/testing/radix-tree/test.h

+0 −1
Original line number Diff line number Diff line
@@ -32,7 +32,6 @@ void item_kill_tree(struct radix_tree_root *root); 
int tag_tagged_items(struct radix_tree_root *, pthread_mutex_t *,

			unsigned long start, unsigned long end, unsigned batch,

			unsigned iftag, unsigned thentag);

unsigned long find_item(struct radix_tree_root *, void *item);



void xarray_tests(void);

void tag_check(void);