maple_tree: Prefilled sheaf conversion and testing

Use prefilled sheaves instead of bulk allocations. This should speed up
the allocations and the return path of unused allocations.

Remove the push and pop of nodes from the maple state as this is now
handled by the slab layer with sheaves.

Testing has been removed as necessary since the features of the tree
have been reduced.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

1 files changed, 62 insertions, 264 deletions

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 0439aaacf6cb..b41245f2cc65 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -182,6 +182,22 @@ static inline void mt_free_bulk(size_t size, void __rcu **nodes)
 	kmem_cache_free_bulk(maple_node_cache, size, (void **)nodes);
 }
 
+static void mt_return_sheaf(struct slab_sheaf *sheaf)
+{
+	kmem_cache_return_sheaf(maple_node_cache, GFP_NOWAIT, sheaf);
+}
+
+static struct slab_sheaf *mt_get_sheaf(gfp_t gfp, int count)
+{
+	return kmem_cache_prefill_sheaf(maple_node_cache, gfp, count);
+}
+
+static int mt_refill_sheaf(gfp_t gfp, struct slab_sheaf **sheaf,
+		unsigned int size)
+{
+	return kmem_cache_refill_sheaf(maple_node_cache, gfp, sheaf, size);
+}
+
 /*
  * ma_free_rcu() - Use rcu callback to free a maple node
  * @node: The node to free
@@ -575,67 +591,6 @@ static __always_inline bool mte_dead_node(const struct maple_enode *enode)
 }
 
 /*
- * mas_allocated() - Get the number of nodes allocated in a maple state.
- * @mas: The maple state
- *
- * The ma_state alloc member is overloaded to hold a pointer to the first
- * allocated node or to the number of requested nodes to allocate.  If bit 0 is
- * set, then the alloc contains the number of requested nodes.  If there is an
- * allocated node, then the total allocated nodes is in that node.
- *
- * Return: The total number of nodes allocated
- */
-static inline unsigned long mas_allocated(const struct ma_state *mas)
-{
-	if (!mas->alloc || ((unsigned long)mas->alloc & 0x1))
-		return 0;
-
-	return mas->alloc->total;
-}
-
-/*
- * mas_set_alloc_req() - Set the requested number of allocations.
- * @mas: the maple state
- * @count: the number of allocations.
- *
- * The requested number of allocations is either in the first allocated node,
- * located in @mas->alloc->request_count, or directly in @mas->alloc if there is
- * no allocated node.  Set the request either in the node or do the necessary
- * encoding to store in @mas->alloc directly.
- */
-static inline void mas_set_alloc_req(struct ma_state *mas, unsigned long count)
-{
-	if (!mas->alloc || ((unsigned long)mas->alloc & 0x1)) {
-		if (!count)
-			mas->alloc = NULL;
-		else
-			mas->alloc = (struct maple_alloc *)(((count) << 1U) | 1U);
-		return;
-	}
-
-	mas->alloc->request_count = count;
-}
-
-/*
- * mas_alloc_req() - get the requested number of allocations.
- * @mas: The maple state
- *
- * The alloc count is either stored directly in @mas, or in
- * @mas->alloc->request_count if there is at least one node allocated.  Decode
- * the request count if it's stored directly in @mas->alloc.
- *
- * Return: The allocation request count.
- */
-static inline unsigned int mas_alloc_req(const struct ma_state *mas)
-{
-	if ((unsigned long)mas->alloc & 0x1)
-		return (unsigned long)(mas->alloc) >> 1;
-	else if (mas->alloc)
-		return mas->alloc->request_count;
-	return 0;
-}
-
-/*
  * ma_pivots() - Get a pointer to the maple node pivots.
  * @node: the maple node
  * @type: the node type
@@ -1120,77 +1075,15 @@ static int mas_ascend(struct ma_state *mas)
  */
 static inline struct maple_node *mas_pop_node(struct ma_state *mas)
 {
-	struct maple_alloc *ret, *node = mas->alloc;
-	unsigned long total = mas_allocated(mas);
-	unsigned int req = mas_alloc_req(mas);
+	struct maple_node *ret;
 
-	/* nothing or a request pending. */
-	if (WARN_ON(!total))
+	if (WARN_ON_ONCE(!mas->sheaf))
 		return NULL;
 
-	if (total == 1) {
-		/* single allocation in this ma_state */
-		mas->alloc = NULL;
-		ret = node;
-		goto single_node;
-	}
-
-	if (node->node_count == 1) {
-		/* Single allocation in this node. */
-		mas->alloc = node->slot[0];
-		mas->alloc->total = node->total - 1;
-		ret = node;
-		goto new_head;
-	}
-	node->total--;
-	ret = node->slot[--node->node_count];
-	node->slot[node->node_count] = NULL;
-
-single_node:
-new_head:
-	if (req) {
-		req++;
-		mas_set_alloc_req(mas, req);
-	}
-
+	ret = kmem_cache_alloc_from_sheaf(maple_node_cache, GFP_NOWAIT, mas->sheaf);
 	memset(ret, 0, sizeof(*ret));
-	return (struct maple_node *)ret;
-}
-
-/*
- * mas_push_node() - Push a node back on the maple state allocation.
- * @mas: The maple state
- * @used: The used maple node
- *
- * Stores the maple node back into @mas->alloc for reuse.  Updates allocated and
- * requested node count as necessary.
- */
-static inline void mas_push_node(struct ma_state *mas, struct maple_node *used)
-{
-	struct maple_alloc *reuse = (struct maple_alloc *)used;
-	struct maple_alloc *head = mas->alloc;
-	unsigned long count;
-	unsigned int requested = mas_alloc_req(mas);
 
-	count = mas_allocated(mas);
-
-	reuse->request_count = 0;
-	reuse->node_count = 0;
-	if (count) {
-		if (head->node_count < MAPLE_ALLOC_SLOTS) {
-			head->slot[head->node_count++] = reuse;
-			head->total++;
-			goto done;
-		}
-		reuse->slot[0] = head;
-		reuse->node_count = 1;
-	}
-
-	reuse->total = count + 1;
-	mas->alloc = reuse;
-done:
-	if (requested > 1)
-		mas_set_alloc_req(mas, requested - 1);
+	return ret;
 }
 
 /*
@@ -1200,75 +1093,32 @@ done:
  */
 static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp)
 {
-	struct maple_alloc *node;
-	unsigned long allocated = mas_allocated(mas);
-	unsigned int requested = mas_alloc_req(mas);
-	unsigned int count;
-	void **slots = NULL;
-	unsigned int max_req = 0;
-
-	if (!requested)
-		return;
+	if (unlikely(mas->sheaf)) {
+		unsigned long refill = mas->node_request;
 
-	mas_set_alloc_req(mas, 0);
-	if (mas->mas_flags & MA_STATE_PREALLOC) {
-		if (allocated)
+		if (kmem_cache_sheaf_size(mas->sheaf) >= refill) {
+			mas->node_request = 0;
 			return;
-		WARN_ON(!allocated);
-	}
-
-	if (!allocated || mas->alloc->node_count == MAPLE_ALLOC_SLOTS) {
-		node = (struct maple_alloc *)mt_alloc_one(gfp);
-		if (!node)
-			goto nomem_one;
-
-		if (allocated) {
-			node->slot[0] = mas->alloc;
-			node->node_count = 1;
-		} else {
-			node->node_count = 0;
 		}
 
-		mas->alloc = node;
-		node->total = ++allocated;
-		node->request_count = 0;
-		requested--;
-	}
+		if (mt_refill_sheaf(gfp, &mas->sheaf, refill))
+			goto error;
 
-	node = mas->alloc;
-	while (requested) {
-		max_req = MAPLE_ALLOC_SLOTS - node->node_count;
-		slots = (void **)&node->slot[node->node_count];
-		max_req = min(requested, max_req);
-		count = mt_alloc_bulk(gfp, max_req, slots);
-		if (!count)
-			goto nomem_bulk;
-
-		if (node->node_count == 0) {
-			node->slot[0]->node_count = 0;
-			node->slot[0]->request_count = 0;
-		}
+		mas->node_request = 0;
+		return;
+	}
 
-		node->node_count += count;
-		allocated += count;
-		/* find a non-full node*/
-		do {
-			node = node->slot[0];
-		} while (unlikely(node->node_count == MAPLE_ALLOC_SLOTS));
-		requested -= count;
+	mas->sheaf = mt_get_sheaf(gfp, mas->node_request);
+	if (likely(mas->sheaf)) {
+		mas->node_request = 0;
+		return;
 	}
-	mas->alloc->total = allocated;
-	return;
 
-nomem_bulk:
-	/* Clean up potential freed allocations on bulk failure */
-	memset(slots, 0, max_req * sizeof(unsigned long));
-	mas->alloc->total = allocated;
-nomem_one:
-	mas_set_alloc_req(mas, requested);
+error:
 	mas_set_err(mas, -ENOMEM);
 }
 
+
 /*
  * mas_free() - Free an encoded maple node
  * @mas: The maple state
@@ -1279,42 +1129,7 @@ nomem_one:
  */
 static inline void mas_free(struct ma_state *mas, struct maple_enode *used)
 {
-	struct maple_node *tmp = mte_to_node(used);
-
-	if (mt_in_rcu(mas->tree))
-		ma_free_rcu(tmp);
-	else
-		mas_push_node(mas, tmp);
-}
-
-/*
- * mas_node_count_gfp() - Check if enough nodes are allocated and request more
- * if there is not enough nodes.
- * @mas: The maple state
- * @count: The number of nodes needed
- * @gfp: the gfp flags
- */
-static void mas_node_count_gfp(struct ma_state *mas, int count, gfp_t gfp)
-{
-	unsigned long allocated = mas_allocated(mas);
-
-	if (allocated < count) {
-		mas_set_alloc_req(mas, count - allocated);
-		mas_alloc_nodes(mas, gfp);
-	}
-}
-
-/*
- * mas_node_count() - Check if enough nodes are allocated and request more if
- * there is not enough nodes.
- * @mas: The maple state
- * @count: The number of nodes needed
- *
- * Note: Uses GFP_NOWAIT for gfp flags.
- */
-static void mas_node_count(struct ma_state *mas, int count)
-{
-	return mas_node_count_gfp(mas, count, GFP_NOWAIT);
+	ma_free_rcu(mte_to_node(used));
 }
 
 /*
@@ -2451,10 +2266,7 @@ static inline void mas_topiary_node(struct ma_state *mas,
 	enode = tmp_mas->node;
 	tmp = mte_to_node(enode);
 	mte_set_node_dead(enode);
-	if (in_rcu)
-		ma_free_rcu(tmp);
-	else
-		mas_push_node(mas, tmp);
+	ma_free_rcu(tmp);
 }
 
 /*
@@ -3980,7 +3792,7 @@ set_content:
  *
  * Return: Number of nodes required for preallocation.
  */
-static inline int mas_prealloc_calc(struct ma_wr_state *wr_mas, void *entry)
+static inline void mas_prealloc_calc(struct ma_wr_state *wr_mas, void *entry)
 {
 	struct ma_state *mas = wr_mas->mas;
 	unsigned char height = mas_mt_height(mas);
@@ -4026,7 +3838,7 @@ static inline int mas_prealloc_calc(struct ma_wr_state *wr_mas, void *entry)
 		WARN_ON_ONCE(1);
 	}
 
-	return ret;
+	mas->node_request = ret;
 }
 
 /*
@@ -4087,15 +3899,15 @@ static inline enum store_type mas_wr_store_type(struct ma_wr_state *wr_mas)
  */
 static inline void mas_wr_preallocate(struct ma_wr_state *wr_mas, void *entry)
 {
-	int request;
+	struct ma_state *mas = wr_mas->mas;
 
 	mas_wr_prealloc_setup(wr_mas);
-	wr_mas->mas->store_type = mas_wr_store_type(wr_mas);
-	request = mas_prealloc_calc(wr_mas, entry);
-	if (!request)
+	mas->store_type = mas_wr_store_type(wr_mas);
+	mas_prealloc_calc(wr_mas, entry);
+	if (!mas->node_request)
 		return;
 
-	mas_node_count(wr_mas->mas, request);
+	mas_alloc_nodes(mas, GFP_NOWAIT);
 }
 
 /**
@@ -5208,7 +5020,6 @@ static inline void mte_destroy_walk(struct maple_enode *enode,
  */
 void *mas_store(struct ma_state *mas, void *entry)
 {
-	int request;
 	MA_WR_STATE(wr_mas, mas, entry);
 
 	trace_ma_write(__func__, mas, 0, entry);
@@ -5238,11 +5049,11 @@ void *mas_store(struct ma_state *mas, void *entry)
 		return wr_mas.content;
 	}
 
-	request = mas_prealloc_calc(&wr_mas, entry);
-	if (!request)
+	mas_prealloc_calc(&wr_mas, entry);
+	if (!mas->node_request)
 		goto store;
 
-	mas_node_count(mas, request);
+	mas_alloc_nodes(mas, GFP_NOWAIT);
 	if (mas_is_err(mas))
 		return NULL;
 
@@ -5330,20 +5141,19 @@ EXPORT_SYMBOL_GPL(mas_store_prealloc);
 int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
 {
 	MA_WR_STATE(wr_mas, mas, entry);
-	int ret = 0;
-	int request;
 
 	mas_wr_prealloc_setup(&wr_mas);
 	mas->store_type = mas_wr_store_type(&wr_mas);
-	request = mas_prealloc_calc(&wr_mas, entry);
-	if (!request)
+	mas_prealloc_calc(&wr_mas, entry);
+	if (!mas->node_request)
 		goto set_flag;
 
 	mas->mas_flags &= ~MA_STATE_PREALLOC;
-	mas_node_count_gfp(mas, request, gfp);
+	mas_alloc_nodes(mas, gfp);
 	if (mas_is_err(mas)) {
-		mas_set_alloc_req(mas, 0);
-		ret = xa_err(mas->node);
+		int ret = xa_err(mas->node);
+
+		mas->node_request = 0;
 		mas_destroy(mas);
 		mas_reset(mas);
 		return ret;
@@ -5351,7 +5161,7 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
 
 set_flag:
 	mas->mas_flags |= MA_STATE_PREALLOC;
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(mas_preallocate);
 
@@ -5365,26 +5175,13 @@ EXPORT_SYMBOL_GPL(mas_preallocate);
  */
 void mas_destroy(struct ma_state *mas)
 {
-	struct maple_alloc *node;
-	unsigned long total;
-
 	mas->mas_flags &= ~MA_STATE_PREALLOC;
 
-	total = mas_allocated(mas);
-	while (total) {
-		node = mas->alloc;
-		mas->alloc = node->slot[0];
-		if (node->node_count > 1) {
-			size_t count = node->node_count - 1;
-
-			mt_free_bulk(count, (void __rcu **)&node->slot[1]);
-			total -= count;
-		}
-		kfree(ma_mnode_ptr(node));
-		total--;
-	}
+	mas->node_request = 0;
+	if (mas->sheaf)
+		mt_return_sheaf(mas->sheaf);
 
-	mas->alloc = NULL;
+	mas->sheaf = NULL;
 }
 EXPORT_SYMBOL_GPL(mas_destroy);
 
@@ -6019,7 +5816,7 @@ bool mas_nomem(struct ma_state *mas, gfp_t gfp)
 		mas_alloc_nodes(mas, gfp);
 	}
 
-	if (!mas_allocated(mas))
+	if (!mas->sheaf)
 		return false;
 
 	mas->status = ma_start;
@@ -7414,8 +7211,9 @@ void mas_dump(const struct ma_state *mas)
 
 	pr_err("[%u/%u] index=%lx last=%lx\n", mas->offset, mas->end,
 	       mas->index, mas->last);
-	pr_err("     min=%lx max=%lx alloc=" PTR_FMT ", depth=%u, flags=%x\n",
-	       mas->min, mas->max, mas->alloc, mas->depth, mas->mas_flags);
+	pr_err("     min=%lx max=%lx sheaf=" PTR_FMT ", request %lu depth=%u, flags=%x\n",
+	       mas->min, mas->max, mas->sheaf, mas->node_request, mas->depth,
+	       mas->mas_flags);
 	if (mas->index > mas->last)
 		pr_err("Check index & last\n");
 }