[PATCH v8 14/63] xarray: Define struct xa_node

From: Matthew Wilcox
Date: Tue Mar 06 2018 - 14:35:00 EST

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From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>

This is a direct replacement for struct radix_tree_node. A couple of
struct members have changed name, so convert those. Use a #define so
that radix tree users continue to work without change.

Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
---
include/linux/radix-tree.h | 29 +++------------------
include/linux/xarray.h | 24 ++++++++++++++++++
lib/radix-tree.c | 48 +++++++++++++++++------------------
mm/workingset.c | 16 ++++++------
tools/testing/radix-tree/multiorder.c | 30 +++++++++++-----------
5 files changed, 74 insertions(+), 73 deletions(-)

diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index c8a33e9e9a3c..f64beb9ba175 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -32,6 +32,7 @@

/* Keep unconverted code working */
#define radix_tree_root xarray
+#define radix_tree_node xa_node

/*
* The bottom two bits of the slot determine how the remaining bits in the
@@ -60,41 +61,17 @@ static inline bool radix_tree_is_internal_node(void *ptr)

/*** radix-tree API starts here ***/

-#define RADIX_TREE_MAX_TAGS 3
-
#define RADIX_TREE_MAP_SHIFT XA_CHUNK_SHIFT
#define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT)
#define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1)

-#define RADIX_TREE_TAG_LONGS \
- ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG)
+#define RADIX_TREE_MAX_TAGS XA_MAX_TAGS
+#define RADIX_TREE_TAG_LONGS XA_TAG_LONGS

#define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
#define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \
RADIX_TREE_MAP_SHIFT))

-/*
- * @count is the count of every non-NULL element in the ->slots array
- * whether that is a data entry, a retry entry, a user pointer,
- * a sibling entry or a pointer to the next level of the tree.
- * @exceptional is the count of every element in ->slots which is
- * either a data entry or a sibling entry for data.
- */
-struct radix_tree_node {
- unsigned char shift; /* Bits remaining in each slot */
- unsigned char offset; /* Slot offset in parent */
- unsigned char count; /* Total entry count */
- unsigned char exceptional; /* Exceptional entry count */
- struct radix_tree_node *parent; /* Used when ascending tree */
- struct radix_tree_root *root; /* The tree we belong to */
- union {
- struct list_head private_list; /* For tree user */
- struct rcu_head rcu_head; /* Used when freeing node */
- };
- void __rcu *slots[RADIX_TREE_MAP_SIZE];
- unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS];
-};
-
/* The IDR tag is stored in the low bits of xa_flags */
#define ROOT_IS_IDR ((__force gfp_t)4)
/* The top bits of xa_flags are used to store the root tags */
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index 9b05b907062b..b51f354dfbf0 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -195,6 +195,30 @@ static inline void xa_init(struct xarray *xa)
#endif
#define XA_CHUNK_SIZE (1UL << XA_CHUNK_SHIFT)
#define XA_CHUNK_MASK (XA_CHUNK_SIZE - 1)
+#define XA_MAX_TAGS 3
+#define XA_TAG_LONGS DIV_ROUND_UP(XA_CHUNK_SIZE, BITS_PER_LONG)
+
+/*
+ * @count is the count of every non-NULL element in the ->slots array
+ * whether that is a value entry, a retry entry, a user pointer,
+ * a sibling entry or a pointer to the next level of the tree.
+ * @nr_values is the count of every element in ->slots which is
+ * either a value entry or a sibling entry to a value entry.
+ */
+struct xa_node {
+ unsigned char shift; /* Bits remaining in each slot */
+ unsigned char offset; /* Slot offset in parent */
+ unsigned char count; /* Total entry count */
+ unsigned char nr_values; /* Value entry count */
+ struct xa_node __rcu *parent; /* NULL at top of tree */
+ struct xarray *array; /* The array we belong to */
+ union {
+ struct list_head private_list; /* For tree user */
+ struct rcu_head rcu_head; /* Used when freeing node */
+ };
+ void __rcu *slots[XA_CHUNK_SIZE];
+ unsigned long tags[XA_MAX_TAGS][XA_TAG_LONGS];
+};

/* Private */
static inline bool xa_is_node(const void *entry)
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index c9ae6e6579f8..e98de16b1648 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -260,11 +260,11 @@ static void dump_node(struct radix_tree_node *node, unsigned long index)
{
unsigned long i;

- pr_debug("radix node: %p offset %d indices %lu-%lu parent %p tags %lx %lx %lx shift %d count %d exceptional %d\n",
+ pr_debug("radix node: %p offset %d indices %lu-%lu parent %p tags %lx %lx %lx shift %d count %d nr_values %d\n",
node, node->offset, index, index | node_maxindex(node),
node->parent,
node->tags[0][0], node->tags[1][0], node->tags[2][0],
- node->shift, node->count, node->exceptional);
+ node->shift, node->count, node->nr_values);

for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) {
unsigned long first = index | (i << node->shift);
@@ -354,7 +354,7 @@ static struct radix_tree_node *
radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent,
struct radix_tree_root *root,
unsigned int shift, unsigned int offset,
- unsigned int count, unsigned int exceptional)
+ unsigned int count, unsigned int nr_values)
{
struct radix_tree_node *ret = NULL;

@@ -401,9 +401,9 @@ radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent,
ret->shift = shift;
ret->offset = offset;
ret->count = count;
- ret->exceptional = exceptional;
+ ret->nr_values = nr_values;
ret->parent = parent;
- ret->root = root;
+ ret->array = root;
}
return ret;
}
@@ -633,8 +633,8 @@ static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp,
if (radix_tree_is_internal_node(entry)) {
entry_to_node(entry)->parent = node;
} else if (xa_is_value(entry)) {
- /* Moving an exceptional root->xa_head to a node */
- node->exceptional = 1;
+ /* Moving a value entry root->xa_head to a node */
+ node->nr_values = 1;
}
/*
* entry was already in the radix tree, so we do not need
@@ -920,12 +920,12 @@ static inline int insert_entries(struct radix_tree_node *node,
if (xa_is_node(old))
radix_tree_free_nodes(old);
if (xa_is_value(old))
- node->exceptional--;
+ node->nr_values--;
}
if (node) {
node->count += n;
if (xa_is_value(item))
- node->exceptional += n;
+ node->nr_values += n;
}
return n;
}
@@ -939,7 +939,7 @@ static inline int insert_entries(struct radix_tree_node *node,
if (node) {
node->count++;
if (xa_is_value(item))
- node->exceptional++;
+ node->nr_values++;
}
return 1;
}
@@ -1073,7 +1073,7 @@ void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index)
EXPORT_SYMBOL(radix_tree_lookup);

static inline void replace_sibling_entries(struct radix_tree_node *node,
- void __rcu **slot, int count, int exceptional)
+ void __rcu **slot, int count, int values)
{
#ifdef CONFIG_RADIX_TREE_MULTIORDER
unsigned offset = get_slot_offset(node, slot);
@@ -1086,21 +1086,21 @@ static inline void replace_sibling_entries(struct radix_tree_node *node,
node->slots[offset] = NULL;
node->count--;
}
- node->exceptional += exceptional;
+ node->nr_values += values;
}
#endif
}

static void replace_slot(void __rcu **slot, void *item,
- struct radix_tree_node *node, int count, int exceptional)
+ struct radix_tree_node *node, int count, int values)
{
if (WARN_ON_ONCE(radix_tree_is_internal_node(item)))
return;

- if (node && (count || exceptional)) {
+ if (node && (count || values)) {
node->count += count;
- node->exceptional += exceptional;
- replace_sibling_entries(node, slot, count, exceptional);
+ node->nr_values += values;
+ replace_sibling_entries(node, slot, count, values);
}

rcu_assign_pointer(*slot, item);
@@ -1154,17 +1154,17 @@ void __radix_tree_replace(struct radix_tree_root *root,
radix_tree_update_node_t update_node)
{
void *old = rcu_dereference_raw(*slot);
- int exceptional = !!xa_is_value(item) - !!xa_is_value(old);
+ int values = !!xa_is_value(item) - !!xa_is_value(old);
int count = calculate_count(root, node, slot, item, old);

/*
- * This function supports replacing exceptional entries and
+ * This function supports replacing value entries and
* deleting entries, but that needs accounting against the
* node unless the slot is root->xa_head.
*/
WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->xa_head) &&
- (count || exceptional));
- replace_slot(slot, item, node, count, exceptional);
+ (count || values));
+ replace_slot(slot, item, node, count, values);

if (!node)
return;
@@ -1186,7 +1186,7 @@ void __radix_tree_replace(struct radix_tree_root *root,
* across slot lookup and replacement.
*
* NOTE: This cannot be used to switch between non-entries (empty slots),
- * regular entries, and exceptional entries, as that requires accounting
+ * regular entries, and value entries, as that requires accounting
* inside the radix tree node. When switching from one type of entry or
* deleting, use __radix_tree_lookup() and __radix_tree_replace() or
* radix_tree_iter_replace().
@@ -1294,7 +1294,7 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
rcu_assign_pointer(parent->slots[end], RADIX_TREE_RETRY);
}
rcu_assign_pointer(parent->slots[offset], RADIX_TREE_RETRY);
- parent->exceptional -= (end - offset);
+ parent->nr_values -= (end - offset);

if (order == parent->shift)
return 0;
@@ -1954,7 +1954,7 @@ static bool __radix_tree_delete(struct radix_tree_root *root,
struct radix_tree_node *node, void __rcu **slot)
{
void *old = rcu_dereference_raw(*slot);
- int exceptional = xa_is_value(old) ? -1 : 0;
+ int values = xa_is_value(old) ? -1 : 0;
unsigned offset = get_slot_offset(node, slot);
int tag;

@@ -1964,7 +1964,7 @@ static bool __radix_tree_delete(struct radix_tree_root *root,
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
node_tag_clear(root, node, tag, offset);

- replace_slot(slot, NULL, node, -1, exceptional);
+ replace_slot(slot, NULL, node, -1, values);
return node && delete_node(root, node, NULL);
}

diff --git a/mm/workingset.c b/mm/workingset.c
index b5dd3936e697..bad4e58881cd 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -348,7 +348,7 @@ void workingset_update_node(struct radix_tree_node *node)
* already where they should be. The list_empty() test is safe
* as node->private_list is protected by the i_pages lock.
*/
- if (node->count && node->count == node->exceptional) {
+ if (node->count && node->count == node->nr_values) {
if (list_empty(&node->private_list))
list_lru_add(&shadow_nodes, &node->private_list);
} else {
@@ -427,8 +427,8 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
* to reclaim, take the node off-LRU, and drop the lru_lock.
*/

- node = container_of(item, struct radix_tree_node, private_list);
- mapping = container_of(node->root, struct address_space, i_pages);
+ node = container_of(item, struct xa_node, private_list);
+ mapping = container_of(node->array, struct address_space, i_pages);

/* Coming from the list, invert the lock order */
if (!xa_trylock(&mapping->i_pages)) {
@@ -445,25 +445,25 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
* no pages, so we expect to be able to remove them all and
* delete and free the empty node afterwards.
*/
- if (WARN_ON_ONCE(!node->exceptional))
+ if (WARN_ON_ONCE(!node->nr_values))
goto out_invalid;
- if (WARN_ON_ONCE(node->count != node->exceptional))
+ if (WARN_ON_ONCE(node->count != node->nr_values))
goto out_invalid;
for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) {
if (node->slots[i]) {
if (WARN_ON_ONCE(!xa_is_value(node->slots[i])))
goto out_invalid;
- if (WARN_ON_ONCE(!node->exceptional))
+ if (WARN_ON_ONCE(!node->nr_values))
goto out_invalid;
if (WARN_ON_ONCE(!mapping->nrexceptional))
goto out_invalid;
node->slots[i] = NULL;
- node->exceptional--;
+ node->nr_values--;
node->count--;
mapping->nrexceptional--;
}
}
- if (WARN_ON_ONCE(node->exceptional))
+ if (WARN_ON_ONCE(node->nr_values))
goto out_invalid;
inc_lruvec_page_state(virt_to_page(node), WORKINGSET_NODERECLAIM);
__radix_tree_delete_node(&mapping->i_pages, node,
diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c
index 24293a2fd82d..ed51edc008fd 100644
--- a/tools/testing/radix-tree/multiorder.c
+++ b/tools/testing/radix-tree/multiorder.c
@@ -392,7 +392,7 @@ static void multiorder_join2(unsigned order1, unsigned order2)
radix_tree_insert(&tree, 1 << order2, xa_mk_value(5));
item2 = __radix_tree_lookup(&tree, 1 << order2, &node, NULL);
assert(item2 == xa_mk_value(5));
- assert(node->exceptional == 1);
+ assert(node->nr_values == 1);

item2 = radix_tree_lookup(&tree, 0);
free(item2);
@@ -400,7 +400,7 @@ static void multiorder_join2(unsigned order1, unsigned order2)
radix_tree_join(&tree, 0, order1, item1);
item2 = __radix_tree_lookup(&tree, 1 << order2, &node, NULL);
assert(item2 == item1);
- assert(node->exceptional == 0);
+ assert(node->nr_values == 0);
item_kill_tree(&tree);
}

@@ -408,7 +408,7 @@ static void multiorder_join2(unsigned order1, unsigned order2)
* This test revealed an accounting bug for inline data entries at one point.
* Nodes were being freed back into the pool with an elevated exception count
* by radix_tree_join() and then radix_tree_split() was failing to zero the
- * count of exceptional entries.
+ * count of value entries.
*/
static void multiorder_join3(unsigned int order)
{
@@ -432,7 +432,7 @@ static void multiorder_join3(unsigned int order)
}

__radix_tree_lookup(&tree, 0, &node, NULL);
- assert(node->exceptional == node->count);
+ assert(node->nr_values == node->count);

item_kill_tree(&tree);
}
@@ -519,7 +519,7 @@ static void __multiorder_split2(int old_order, int new_order)

item = __radix_tree_lookup(&tree, 0, &node, NULL);
assert(item == xa_mk_value(5));
- assert(node->exceptional > 0);
+ assert(node->nr_values > 0);

radix_tree_split(&tree, 0, new_order);
radix_tree_for_each_slot(slot, &tree, &iter, 0) {
@@ -529,7 +529,7 @@ static void __multiorder_split2(int old_order, int new_order)

item = __radix_tree_lookup(&tree, 0, &node, NULL);
assert(item != xa_mk_value(5));
- assert(node->exceptional == 0);
+ assert(node->nr_values == 0);

item_kill_tree(&tree);
}
@@ -546,7 +546,7 @@ static void __multiorder_split3(int old_order, int new_order)

item = __radix_tree_lookup(&tree, 0, &node, NULL);
assert(item == xa_mk_value(5));
- assert(node->exceptional > 0);
+ assert(node->nr_values > 0);

radix_tree_split(&tree, 0, new_order);
radix_tree_for_each_slot(slot, &tree, &iter, 0) {
@@ -555,7 +555,7 @@ static void __multiorder_split3(int old_order, int new_order)

item = __radix_tree_lookup(&tree, 0, &node, NULL);
assert(item == xa_mk_value(7));
- assert(node->exceptional > 0);
+ assert(node->nr_values > 0);

item_kill_tree(&tree);

@@ -563,7 +563,7 @@ static void __multiorder_split3(int old_order, int new_order)

item = __radix_tree_lookup(&tree, 0, &node, NULL);
assert(item == xa_mk_value(5));
- assert(node->exceptional > 0);
+ assert(node->nr_values > 0);

radix_tree_split(&tree, 0, new_order);
radix_tree_for_each_slot(slot, &tree, &iter, 0) {
@@ -576,13 +576,13 @@ static void __multiorder_split3(int old_order, int new_order)

item = __radix_tree_lookup(&tree, 1 << new_order, &node, NULL);
assert(item == xa_mk_value(7));
- assert(node->count == node->exceptional);
+ assert(node->count == node->nr_values);
do {
node = node->parent;
if (!node)
break;
assert(node->count == 1);
- assert(node->exceptional == 0);
+ assert(node->nr_values == 0);
} while (1);

item_kill_tree(&tree);
@@ -610,15 +610,15 @@ static void multiorder_account(void)

__radix_tree_insert(&tree, 1 << 5, 5, xa_mk_value(5));
__radix_tree_lookup(&tree, 0, &node, NULL);
- assert(node->count == node->exceptional * 2);
+ assert(node->count == node->nr_values * 2);
radix_tree_delete(&tree, 1 << 5);
- assert(node->exceptional == 0);
+ assert(node->nr_values == 0);

__radix_tree_insert(&tree, 1 << 5, 5, xa_mk_value(5));
__radix_tree_lookup(&tree, 1 << 5, &node, &slot);
- assert(node->count == node->exceptional * 2);
+ assert(node->count == node->nr_values * 2);
__radix_tree_replace(&tree, node, slot, NULL, NULL);
- assert(node->exceptional == 0);
+ assert(node->nr_values == 0);

item_kill_tree(&tree);
}
--
2.16.1

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