Merge e15e06a839 ("lib/test_maple_tree: add testing for maple tree") into android-mainline

Steps on the way to 6.1-rc1

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Id639701170c1b427abbd641d3f133dbdc1d93e06

Documentation/core-api/index.rst

@@ -37,6 +37,7 @@ Library functionality that is used throughout the kernel.
    kref
    assoc_array
    xarray
+   maple_tree
    idr
    circular-buffers
    rbtree

Documentation/core-api/maple_tree.rst

@@ -0,0 +1,217 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+
+==========
+Maple Tree
+==========
+
+:Author: Liam R. Howlett
+
+Overview
+========
+
+The Maple Tree is a B-Tree data type which is optimized for storing
+non-overlapping ranges, including ranges of size 1.  The tree was designed to
+be simple to use and does not require a user written search method.  It
+supports iterating over a range of entries and going to the previous or next
+entry in a cache-efficient manner.  The tree can also be put into an RCU-safe
+mode of operation which allows reading and writing concurrently.  Writers must
+synchronize on a lock, which can be the default spinlock, or the user can set
+the lock to an external lock of a different type.
+
+The Maple Tree maintains a small memory footprint and was designed to use
+modern processor cache efficiently.  The majority of the users will be able to
+use the normal API.  An :ref:`maple-tree-advanced-api` exists for more complex
+scenarios.  The most important usage of the Maple Tree is the tracking of the
+virtual memory areas.
+
+The Maple Tree can store values between ``0`` and ``ULONG_MAX``.  The Maple
+Tree reserves values with the bottom two bits set to '10' which are below 4096
+(ie 2, 6, 10 .. 4094) for internal use.  If the entries may use reserved
+entries then the users can convert the entries using xa_mk_value() and convert
+them back by calling xa_to_value().  If the user needs to use a reserved
+value, then the user can convert the value when using the
+:ref:`maple-tree-advanced-api`, but are blocked by the normal API.
+
+The Maple Tree can also be configured to support searching for a gap of a given
+size (or larger).
+
+Pre-allocating of nodes is also supported using the
+:ref:`maple-tree-advanced-api`.  This is useful for users who must guarantee a
+successful store operation within a given
+code segment when allocating cannot be done.  Allocations of nodes are
+relatively small at around 256 bytes.
+
+.. _maple-tree-normal-api:
+
+Normal API
+==========
+
+Start by initialising a maple tree, either with DEFINE_MTREE() for statically
+allocated maple trees or mt_init() for dynamically allocated ones.  A
+freshly-initialised maple tree contains a ``NULL`` pointer for the range ``0``
+- ``ULONG_MAX``.  There are currently two types of maple trees supported: the
+allocation tree and the regular tree.  The regular tree has a higher branching
+factor for internal nodes.  The allocation tree has a lower branching factor
+but allows the user to search for a gap of a given size or larger from either
+``0`` upwards or ``ULONG_MAX`` down.  An allocation tree can be used by
+passing in the ``MT_FLAGS_ALLOC_RANGE`` flag when initialising the tree.
+
+You can then set entries using mtree_store() or mtree_store_range().
+mtree_store() will overwrite any entry with the new entry and return 0 on
+success or an error code otherwise.  mtree_store_range() works in the same way
+but takes a range.  mtree_load() is used to retrieve the entry stored at a
+given index.  You can use mtree_erase() to erase an entire range by only
+knowing one value within that range, or mtree_store() call with an entry of
+NULL may be used to partially erase a range or many ranges at once.
+
+If you want to only store a new entry to a range (or index) if that range is
+currently ``NULL``, you can use mtree_insert_range() or mtree_insert() which
+return -EEXIST if the range is not empty.
+
+You can search for an entry from an index upwards by using mt_find().
+
+You can walk each entry within a range by calling mt_for_each().  You must
+provide a temporary variable to store a cursor.  If you want to walk each
+element of the tree then ``0`` and ``ULONG_MAX`` may be used as the range.  If
+the caller is going to hold the lock for the duration of the walk then it is
+worth looking at the mas_for_each() API in the :ref:`maple-tree-advanced-api`
+section.
+
+Sometimes it is necessary to ensure the next call to store to a maple tree does
+not allocate memory, please see :ref:`maple-tree-advanced-api` for this use case.
+
+Finally, you can remove all entries from a maple tree by calling
+mtree_destroy().  If the maple tree entries are pointers, you may wish to free
+the entries first.
+
+Allocating Nodes
+----------------
+
+The allocations are handled by the internal tree code.  See
+:ref:`maple-tree-advanced-alloc` for other options.
+
+Locking
+-------
+
+You do not have to worry about locking.  See :ref:`maple-tree-advanced-locks`
+for other options.
+
+The Maple Tree uses RCU and an internal spinlock to synchronise access:
+
+Takes RCU read lock:
+ * mtree_load()
+ * mt_find()
+ * mt_for_each()
+ * mt_next()
+ * mt_prev()
+
+Takes ma_lock internally:
+ * mtree_store()
+ * mtree_store_range()
+ * mtree_insert()
+ * mtree_insert_range()
+ * mtree_erase()
+ * mtree_destroy()
+ * mt_set_in_rcu()
+ * mt_clear_in_rcu()
+
+If you want to take advantage of the internal lock to protect the data
+structures that you are storing in the Maple Tree, you can call mtree_lock()
+before calling mtree_load(), then take a reference count on the object you
+have found before calling mtree_unlock().  This will prevent stores from
+removing the object from the tree between looking up the object and
+incrementing the refcount.  You can also use RCU to avoid dereferencing
+freed memory, but an explanation of that is beyond the scope of this
+document.
+
+.. _maple-tree-advanced-api:
+
+Advanced API
+============
+
+The advanced API offers more flexibility and better performance at the
+cost of an interface which can be harder to use and has fewer safeguards.
+You must take care of your own locking while using the advanced API.
+You can use the ma_lock, RCU or an external lock for protection.
+You can mix advanced and normal operations on the same array, as long
+as the locking is compatible.  The :ref:`maple-tree-normal-api` is implemented
+in terms of the advanced API.
+
+The advanced API is based around the ma_state, this is where the 'mas'
+prefix originates.  The ma_state struct keeps track of tree operations to make
+life easier for both internal and external tree users.
+
+Initialising the maple tree is the same as in the :ref:`maple-tree-normal-api`.
+Please see above.
+
+The maple state keeps track of the range start and end in mas->index and
+mas->last, respectively.
+
+mas_walk() will walk the tree to the location of mas->index and set the
+mas->index and mas->last according to the range for the entry.
+
+You can set entries using mas_store().  mas_store() will overwrite any entry
+with the new entry and return the first existing entry that is overwritten.
+The range is passed in as members of the maple state: index and last.
+
+You can use mas_erase() to erase an entire range by setting index and
+last of the maple state to the desired range to erase.  This will erase
+the first range that is found in that range, set the maple state index
+and last as the range that was erased and return the entry that existed
+at that location.
+
+You can walk each entry within a range by using mas_for_each().  If you want
+to walk each element of the tree then ``0`` and ``ULONG_MAX`` may be used as
+the range.  If the lock needs to be periodically dropped, see the locking
+section mas_pause().
+
+Using a maple state allows mas_next() and mas_prev() to function as if the
+tree was a linked list.  With such a high branching factor the amortized
+performance penalty is outweighed by cache optimization.  mas_next() will
+return the next entry which occurs after the entry at index.  mas_prev()
+will return the previous entry which occurs before the entry at index.
+
+mas_find() will find the first entry which exists at or above index on
+the first call, and the next entry from every subsequent calls.
+
+mas_find_rev() will find the fist entry which exists at or below the last on
+the first call, and the previous entry from every subsequent calls.
+
+If the user needs to yield the lock during an operation, then the maple state
+must be paused using mas_pause().
+
+There are a few extra interfaces provided when using an allocation tree.
+If you wish to search for a gap within a range, then mas_empty_area()
+or mas_empty_area_rev() can be used.  mas_empty_area() searches for a gap
+starting at the lowest index given up to the maximum of the range.
+mas_empty_area_rev() searches for a gap starting at the highest index given
+and continues downward to the lower bound of the range.
+
+.. _maple-tree-advanced-alloc:
+
+Advanced Allocating Nodes
+-------------------------
+
+Allocations are usually handled internally to the tree, however if allocations
+need to occur before a write occurs then calling mas_expected_entries() will
+allocate the worst-case number of needed nodes to insert the provided number of
+ranges.  This also causes the tree to enter mass insertion mode.  Once
+insertions are complete calling mas_destroy() on the maple state will free the
+unused allocations.
+
+.. _maple-tree-advanced-locks:
+
+Advanced Locking
+----------------
+
+The maple tree uses a spinlock by default, but external locks can be used for
+tree updates as well.  To use an external lock, the tree must be initialized
+with the ``MT_FLAGS_LOCK_EXTERN flag``, this is usually done with the
+MTREE_INIT_EXT() #define, which takes an external lock as an argument.
+
+Functions and structures
+========================
+
+.. kernel-doc:: include/linux/maple_tree.h
+.. kernel-doc:: lib/maple_tree.c

MAINTAINERS

@@ -12175,6 +12175,18 @@ L:	linux-man@vger.kernel.org
 S:	Maintained
 W:	http://www.kernel.org/doc/man-pages
 
+MAPLE TREE
+M:	Liam R. Howlett <Liam.Howlett@oracle.com>
+L:	linux-mm@kvack.org
+S:	Supported
+F:	Documentation/core-api/maple_tree.rst
+F:	include/linux/maple_tree.h
+F:	include/trace/events/maple_tree.h
+F:	lib/maple_tree.c
+F:	lib/test_maple_tree.c
+F:	tools/testing/radix-tree/linux/maple_tree.h
+F:	tools/testing/radix-tree/maple.c
+
 MARDUK (CREATOR CI40) DEVICE TREE SUPPORT
 M:	Rahul Bedarkar <rahulbedarkar89@gmail.com>
 L:	linux-mips@vger.kernel.org

include/linux/maple_tree.h

@@ -0,0 +1,685 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef _LINUX_MAPLE_TREE_H
+#define _LINUX_MAPLE_TREE_H
+/*
+ * Maple Tree - An RCU-safe adaptive tree for storing ranges
+ * Copyright (c) 2018-2022 Oracle
+ * Authors:     Liam R. Howlett <Liam.Howlett@Oracle.com>
+ *              Matthew Wilcox <willy@infradead.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/rcupdate.h>
+#include <linux/spinlock.h>
+/* #define CONFIG_MAPLE_RCU_DISABLED */
+/* #define CONFIG_DEBUG_MAPLE_TREE_VERBOSE */
+
+/*
+ * Allocated nodes are mutable until they have been inserted into the tree,
+ * at which time they cannot change their type until they have been removed
+ * from the tree and an RCU grace period has passed.
+ *
+ * Removed nodes have their ->parent set to point to themselves.  RCU readers
+ * check ->parent before relying on the value that they loaded from the
+ * slots array.  This lets us reuse the slots array for the RCU head.
+ *
+ * Nodes in the tree point to their parent unless bit 0 is set.
+ */
+#if defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64)
+/* 64bit sizes */
+#define MAPLE_NODE_SLOTS	31	/* 256 bytes including ->parent */
+#define MAPLE_RANGE64_SLOTS	16	/* 256 bytes */
+#define MAPLE_ARANGE64_SLOTS	10	/* 240 bytes */
+#define MAPLE_ARANGE64_META_MAX	15	/* Out of range for metadata */
+#define MAPLE_ALLOC_SLOTS	(MAPLE_NODE_SLOTS - 1)
+#else
+/* 32bit sizes */
+#define MAPLE_NODE_SLOTS	63	/* 256 bytes including ->parent */
+#define MAPLE_RANGE64_SLOTS	32	/* 256 bytes */
+#define MAPLE_ARANGE64_SLOTS	21	/* 240 bytes */
+#define MAPLE_ARANGE64_META_MAX	31	/* Out of range for metadata */
+#define MAPLE_ALLOC_SLOTS	(MAPLE_NODE_SLOTS - 2)
+#endif /* defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64) */
+
+#define MAPLE_NODE_MASK		255UL
+
+/*
+ * The node->parent of the root node has bit 0 set and the rest of the pointer
+ * is a pointer to the tree itself.  No more bits are available in this pointer
+ * (on m68k, the data structure may only be 2-byte aligned).
+ *
+ * Internal non-root nodes can only have maple_range_* nodes as parents.  The
+ * parent pointer is 256B aligned like all other tree nodes.  When storing a 32
+ * or 64 bit values, the offset can fit into 4 bits.  The 16 bit values need an
+ * extra bit to store the offset.  This extra bit comes from a reuse of the last
+ * bit in the node type.  This is possible by using bit 1 to indicate if bit 2
+ * is part of the type or the slot.
+ *
+ * Once the type is decided, the decision of an allocation range type or a range
+ * type is done by examining the immutable tree flag for the MAPLE_ALLOC_RANGE
+ * flag.
+ *
+ *  Node types:
+ *   0x??1 = Root
+ *   0x?00 = 16 bit nodes
+ *   0x010 = 32 bit nodes
+ *   0x110 = 64 bit nodes
+ *
+ *  Slot size and location in the parent pointer:
+ *   type  : slot location
+ *   0x??1 : Root
+ *   0x?00 : 16 bit values, type in 0-1, slot in 2-6
+ *   0x010 : 32 bit values, type in 0-2, slot in 3-6
+ *   0x110 : 64 bit values, type in 0-2, slot in 3-6
+ */
+
+/*
+ * This metadata is used to optimize the gap updating code and in reverse
+ * searching for gaps or any other code that needs to find the end of the data.
+ */
+struct maple_metadata {
+	unsigned char end;
+	unsigned char gap;
+};
+
+/*
+ * Leaf nodes do not store pointers to nodes, they store user data.  Users may
+ * store almost any bit pattern.  As noted above, the optimisation of storing an
+ * entry at 0 in the root pointer cannot be done for data which have the bottom
+ * two bits set to '10'.  We also reserve values with the bottom two bits set to
+ * '10' which are below 4096 (ie 2, 6, 10 .. 4094) for internal use.  Some APIs
+ * return errnos as a negative errno shifted right by two bits and the bottom
+ * two bits set to '10', and while choosing to store these values in the array
+ * is not an error, it may lead to confusion if you're testing for an error with
+ * mas_is_err().
+ *
+ * Non-leaf nodes store the type of the node pointed to (enum maple_type in bits
+ * 3-6), bit 2 is reserved.  That leaves bits 0-1 unused for now.
+ *
+ * In regular B-Tree terms, pivots are called keys.  The term pivot is used to
+ * indicate that the tree is specifying ranges,  Pivots may appear in the
+ * subtree with an entry attached to the value whereas keys are unique to a
+ * specific position of a B-tree.  Pivot values are inclusive of the slot with
+ * the same index.
+ */
+
+struct maple_range_64 {
+	struct maple_pnode *parent;
+	unsigned long pivot[MAPLE_RANGE64_SLOTS - 1];
+	union {
+		void __rcu *slot[MAPLE_RANGE64_SLOTS];
+		struct {
+			void __rcu *pad[MAPLE_RANGE64_SLOTS - 1];
+			struct maple_metadata meta;
+		};
+	};
+};
+
+/*
+ * At tree creation time, the user can specify that they're willing to trade off
+ * storing fewer entries in a tree in return for storing more information in
+ * each node.
+ *
+ * The maple tree supports recording the largest range of NULL entries available
+ * in this node, also called gaps.  This optimises the tree for allocating a
+ * range.
+ */
+struct maple_arange_64 {
+	struct maple_pnode *parent;
+	unsigned long pivot[MAPLE_ARANGE64_SLOTS - 1];
+	void __rcu *slot[MAPLE_ARANGE64_SLOTS];
+	unsigned long gap[MAPLE_ARANGE64_SLOTS];
+	struct maple_metadata meta;
+};
+
+struct maple_alloc {
+	unsigned long total;
+	unsigned char node_count;
+	unsigned int request_count;
+	struct maple_alloc *slot[MAPLE_ALLOC_SLOTS];
+};
+
+struct maple_topiary {
+	struct maple_pnode *parent;
+	struct maple_enode *next; /* Overlaps the pivot */
+};
+
+enum maple_type {
+	maple_dense,
+	maple_leaf_64,
+	maple_range_64,
+	maple_arange_64,
+};
+
+
+/**
+ * DOC: Maple tree flags
+ *
+ * * MT_FLAGS_ALLOC_RANGE	- Track gaps in this tree
+ * * MT_FLAGS_USE_RCU		- Operate in RCU mode
+ * * MT_FLAGS_HEIGHT_OFFSET	- The position of the tree height in the flags
+ * * MT_FLAGS_HEIGHT_MASK	- The mask for the maple tree height value
+ * * MT_FLAGS_LOCK_MASK		- How the mt_lock is used
+ * * MT_FLAGS_LOCK_IRQ		- Acquired irq-safe
+ * * MT_FLAGS_LOCK_BH		- Acquired bh-safe
+ * * MT_FLAGS_LOCK_EXTERN	- mt_lock is not used
+ *
+ * MAPLE_HEIGHT_MAX	The largest height that can be stored
+ */
+#define MT_FLAGS_ALLOC_RANGE	0x01
+#define MT_FLAGS_USE_RCU	0x02
+#define MT_FLAGS_HEIGHT_OFFSET	0x02
+#define MT_FLAGS_HEIGHT_MASK	0x7C
+#define MT_FLAGS_LOCK_MASK	0x300
+#define MT_FLAGS_LOCK_IRQ	0x100
+#define MT_FLAGS_LOCK_BH	0x200
+#define MT_FLAGS_LOCK_EXTERN	0x300
+
+#define MAPLE_HEIGHT_MAX	31
+
+
+#define MAPLE_NODE_TYPE_MASK	0x0F
+#define MAPLE_NODE_TYPE_SHIFT	0x03
+
+#define MAPLE_RESERVED_RANGE	4096
+
+#ifdef CONFIG_LOCKDEP
+typedef struct lockdep_map *lockdep_map_p;
+#define mt_lock_is_held(mt)	lock_is_held(mt->ma_external_lock)
+#define mt_set_external_lock(mt, lock)					\
+	(mt)->ma_external_lock = &(lock)->dep_map
+#else
+typedef struct { /* nothing */ } lockdep_map_p;
+#define mt_lock_is_held(mt)	1
+#define mt_set_external_lock(mt, lock)	do { } while (0)
+#endif
+
+/*
+ * If the tree contains a single entry at index 0, it is usually stored in
+ * tree->ma_root.  To optimise for the page cache, an entry which ends in '00',
+ * '01' or '11' is stored in the root, but an entry which ends in '10' will be
+ * stored in a node.  Bits 3-6 are used to store enum maple_type.
+ *
+ * The flags are used both to store some immutable information about this tree
+ * (set at tree creation time) and dynamic information set under the spinlock.
+ *
+ * Another use of flags are to indicate global states of the tree.  This is the
+ * case with the MAPLE_USE_RCU flag, which indicates the tree is currently in
+ * RCU mode.  This mode was added to allow the tree to reuse nodes instead of
+ * re-allocating and RCU freeing nodes when there is a single user.
+ */
+struct maple_tree {
+	union {
+		spinlock_t	ma_lock;
+		lockdep_map_p	ma_external_lock;
+	};
+	void __rcu      *ma_root;
+	unsigned int	ma_flags;
+};
+
+/**
+ * MTREE_INIT() - Initialize a maple tree
+ * @name: The maple tree name
+ * @__flags: The maple tree flags
+ *
+ */
+#define MTREE_INIT(name, __flags) {					\
+	.ma_lock = __SPIN_LOCK_UNLOCKED((name).ma_lock),		\
+	.ma_flags = __flags,						\
+	.ma_root = NULL,						\
+}
+
+/**
+ * MTREE_INIT_EXT() - Initialize a maple tree with an external lock.
+ * @name: The tree name
+ * @__flags: The maple tree flags
+ * @__lock: The external lock
+ */
+#ifdef CONFIG_LOCKDEP
+#define MTREE_INIT_EXT(name, __flags, __lock) {				\
+	.ma_external_lock = &(__lock).dep_map,				\
+	.ma_flags = (__flags),						\
+	.ma_root = NULL,						\
+}
+#else
+#define MTREE_INIT_EXT(name, __flags, __lock)	MTREE_INIT(name, __flags)
+#endif
+
+#define DEFINE_MTREE(name)						\
+	struct maple_tree name = MTREE_INIT(name, 0)
+
+#define mtree_lock(mt)		spin_lock((&(mt)->ma_lock))
+#define mtree_unlock(mt)	spin_unlock((&(mt)->ma_lock))
+
+/*
+ * The Maple Tree squeezes various bits in at various points which aren't
+ * necessarily obvious.  Usually, this is done by observing that pointers are
+ * N-byte aligned and thus the bottom log_2(N) bits are available for use.  We
+ * don't use the high bits of pointers to store additional information because
+ * we don't know what bits are unused on any given architecture.
+ *
+ * Nodes are 256 bytes in size and are also aligned to 256 bytes, giving us 8
+ * low bits for our own purposes.  Nodes are currently of 4 types:
+ * 1. Single pointer (Range is 0-0)
+ * 2. Non-leaf Allocation Range nodes
+ * 3. Non-leaf Range nodes
+ * 4. Leaf Range nodes All nodes consist of a number of node slots,
+ *    pivots, and a parent pointer.
+ */
+
+struct maple_node {
+	union {
+		struct {
+			struct maple_pnode *parent;
+			void __rcu *slot[MAPLE_NODE_SLOTS];
+		};
+		struct {
+			void *pad;
+			struct rcu_head rcu;
+			struct maple_enode *piv_parent;
+			unsigned char parent_slot;
+			enum maple_type type;
+			unsigned char slot_len;
+			unsigned int ma_flags;
+		};
+		struct maple_range_64 mr64;
+		struct maple_arange_64 ma64;
+		struct maple_alloc alloc;
+	};
+};
+
+/*
+ * More complicated stores can cause two nodes to become one or three and
+ * potentially alter the height of the tree.  Either half of the tree may need
+ * to be rebalanced against the other.  The ma_topiary struct is used to track
+ * which nodes have been 'cut' from the tree so that the change can be done
+ * safely at a later date.  This is done to support RCU.
+ */
+struct ma_topiary {
+	struct maple_enode *head;
+	struct maple_enode *tail;
+	struct maple_tree *mtree;
+};
+
+void *mtree_load(struct maple_tree *mt, unsigned long index);
+
+int mtree_insert(struct maple_tree *mt, unsigned long index,
+		void *entry, gfp_t gfp);
+int mtree_insert_range(struct maple_tree *mt, unsigned long first,
+		unsigned long last, void *entry, gfp_t gfp);
+int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp,
+		void *entry, unsigned long size, unsigned long min,
+		unsigned long max, gfp_t gfp);
+int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp,
+		void *entry, unsigned long size, unsigned long min,
+		unsigned long max, gfp_t gfp);
+
+int mtree_store_range(struct maple_tree *mt, unsigned long first,
+		      unsigned long last, void *entry, gfp_t gfp);
+int mtree_store(struct maple_tree *mt, unsigned long index,
+		void *entry, gfp_t gfp);
+void *mtree_erase(struct maple_tree *mt, unsigned long index);
+
+void mtree_destroy(struct maple_tree *mt);
+void __mt_destroy(struct maple_tree *mt);
+
+/**
+ * mtree_empty() - Determine if a tree has any present entries.
+ * @mt: Maple Tree.
+ *
+ * Context: Any context.
+ * Return: %true if the tree contains only NULL pointers.
+ */
+static inline bool mtree_empty(const struct maple_tree *mt)
+{
+	return mt->ma_root == NULL;
+}
+
+/* Advanced API */
+
+/*
+ * The maple state is defined in the struct ma_state and is used to keep track
+ * of information during operations, and even between operations when using the
+ * advanced API.
+ *
+ * If state->node has bit 0 set then it references a tree location which is not
+ * a node (eg the root).  If bit 1 is set, the rest of the bits are a negative
+ * errno.  Bit 2 (the 'unallocated slots' bit) is clear.  Bits 3-6 indicate the
+ * node type.
+ *
+ * state->alloc either has a request number of nodes or an allocated node.  If
+ * stat->alloc has a requested number of nodes, the first bit will be set (0x1)
+ * and the remaining bits are the value.  If state->alloc is a node, then the
+ * node will be of type maple_alloc.  maple_alloc has MAPLE_NODE_SLOTS - 1 for
+ * storing more allocated nodes, a total number of nodes allocated, and the
+ * node_count in this node.  node_count is the number of allocated nodes in this
+ * node.  The scaling beyond MAPLE_NODE_SLOTS - 1 is handled by storing further
+ * nodes into state->alloc->slot[0]'s node.  Nodes are taken from state->alloc
+ * by removing a node from the state->alloc node until state->alloc->node_count
+ * is 1, when state->alloc is returned and the state->alloc->slot[0] is promoted
+ * to state->alloc.  Nodes are pushed onto state->alloc by putting the current
+ * state->alloc into the pushed node's slot[0].
+ *
+ * The state also contains the implied min/max of the state->node, the depth of
+ * this search, and the offset. The implied min/max are either from the parent
+ * node or are 0-oo for the root node.  The depth is incremented or decremented
+ * every time a node is walked down or up.  The offset is the slot/pivot of
+ * interest in the node - either for reading or writing.
+ *
+ * When returning a value the maple state index and last respectively contain
+ * the start and end of the range for the entry.  Ranges are inclusive in the
+ * Maple Tree.
+ */
+struct ma_state {
+	struct maple_tree *tree;	/* The tree we're operating in */
+	unsigned long index;		/* The index we're operating on - range start */
+	unsigned long last;		/* The last index we're operating on - range end */
+	struct maple_enode *node;	/* The node containing this entry */
+	unsigned long min;		/* The minimum index of this node - implied pivot min */
+	unsigned long max;		/* The maximum index of this node - implied pivot max */
+	struct maple_alloc *alloc;	/* Allocated nodes for this operation */
+	unsigned char depth;		/* depth of tree descent during write */
+	unsigned char offset;
+	unsigned char mas_flags;
+};
+
+struct ma_wr_state {
+	struct ma_state *mas;
+	struct maple_node *node;	/* Decoded mas->node */
+	unsigned long r_min;		/* range min */
+	unsigned long r_max;		/* range max */
+	enum maple_type type;		/* mas->node type */
+	unsigned char offset_end;	/* The offset where the write ends */
+	unsigned char node_end;		/* mas->node end */
+	unsigned long *pivots;		/* mas->node->pivots pointer */
+	unsigned long end_piv;		/* The pivot at the offset end */
+	void __rcu **slots;		/* mas->node->slots pointer */
+	void *entry;			/* The entry to write */
+	void *content;			/* The existing entry that is being overwritten */
+};
+
+#define mas_lock(mas)           spin_lock(&((mas)->tree->ma_lock))
+#define mas_unlock(mas)         spin_unlock(&((mas)->tree->ma_lock))
+
+
+/*
+ * Special values for ma_state.node.
+ * MAS_START means we have not searched the tree.
+ * MAS_ROOT means we have searched the tree and the entry we found lives in
+ * the root of the tree (ie it has index 0, length 1 and is the only entry in
+ * the tree).
+ * MAS_NONE means we have searched the tree and there is no node in the
+ * tree for this entry.  For example, we searched for index 1 in an empty
+ * tree.  Or we have a tree which points to a full leaf node and we
+ * searched for an entry which is larger than can be contained in that
+ * leaf node.
+ * MA_ERROR represents an errno.  After dropping the lock and attempting
+ * to resolve the error, the walk would have to be restarted from the
+ * top of the tree as the tree may have been modified.
+ */
+#define MAS_START	((struct maple_enode *)1UL)
+#define MAS_ROOT	((struct maple_enode *)5UL)
+#define MAS_NONE	((struct maple_enode *)9UL)
+#define MAS_PAUSE	((struct maple_enode *)17UL)
+#define MA_ERROR(err) \
+		((struct maple_enode *)(((unsigned long)err << 2) | 2UL))
+
+#define MA_STATE(name, mt, first, end)					\
+	struct ma_state name = {					\
+		.tree = mt,						\
+		.index = first,						\
+		.last = end,						\
+		.node = MAS_START,					\
+		.min = 0,						\
+		.max = ULONG_MAX,					\
+		.alloc = NULL,						\
+	}
+
+#define MA_WR_STATE(name, ma_state, wr_entry)				\
+	struct ma_wr_state name = {					\
+		.mas = ma_state,					\
+		.content = NULL,					\
+		.entry = wr_entry,					\
+	}
+
+#define MA_TOPIARY(name, tree)						\
+	struct ma_topiary name = {					\
+		.head = NULL,						\
+		.tail = NULL,						\
+		.mtree = tree,						\
+	}
+
+void *mas_walk(struct ma_state *mas);
+void *mas_store(struct ma_state *mas, void *entry);
+void *mas_erase(struct ma_state *mas);
+int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp);
+void mas_store_prealloc(struct ma_state *mas, void *entry);
+void *mas_find(struct ma_state *mas, unsigned long max);
+void *mas_find_rev(struct ma_state *mas, unsigned long min);
+int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp);
+bool mas_is_err(struct ma_state *mas);
+
+bool mas_nomem(struct ma_state *mas, gfp_t gfp);
+void mas_pause(struct ma_state *mas);
+void maple_tree_init(void);
+void mas_destroy(struct ma_state *mas);
+int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries);
+
+void *mas_prev(struct ma_state *mas, unsigned long min);
+void *mas_next(struct ma_state *mas, unsigned long max);
+
+int mas_empty_area(struct ma_state *mas, unsigned long min, unsigned long max,
+		   unsigned long size);
+
+/* Checks if a mas has not found anything */
+static inline bool mas_is_none(struct ma_state *mas)
+{
+	return mas->node == MAS_NONE;
+}
+
+/* Checks if a mas has been paused */
+static inline bool mas_is_paused(struct ma_state *mas)
+{
+	return mas->node == MAS_PAUSE;
+}
+
+void mas_dup_tree(struct ma_state *oldmas, struct ma_state *mas);
+void mas_dup_store(struct ma_state *mas, void *entry);
+
+/*
+ * This finds an empty area from the highest address to the lowest.
+ * AKA "Topdown" version,
+ */
+int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
+		       unsigned long max, unsigned long size);
+/**
+ * mas_reset() - Reset a Maple Tree operation state.
+ * @mas: Maple Tree operation state.
+ *
+ * Resets the error or walk state of the @mas so future walks of the
+ * array will start from the root.  Use this if you have dropped the
+ * lock and want to reuse the ma_state.
+ *
+ * Context: Any context.
+ */
+static inline void mas_reset(struct ma_state *mas)
+{
+	mas->node = MAS_START;
+}
+
+/**
+ * mas_for_each() - Iterate over a range of the maple tree.
+ * @__mas: Maple Tree operation state (maple_state)
+ * @__entry: Entry retrieved from the tree
+ * @__max: maximum index to retrieve from the tree
+ *
+ * When returned, mas->index and mas->last will hold the entire range for the
+ * entry.
+ *
+ * Note: may return the zero entry.
+ *
+ */
+#define mas_for_each(__mas, __entry, __max) \
+	while (((__entry) = mas_find((__mas), (__max))) != NULL)
+
+
+/**
+ * mas_set_range() - Set up Maple Tree operation state for a different index.
+ * @mas: Maple Tree operation state.
+ * @start: New start of range in the Maple Tree.
+ * @last: New end of range in the Maple Tree.
+ *
+ * Move the operation state to refer to a different range.  This will
+ * have the effect of starting a walk from the top; see mas_next()
+ * to move to an adjacent index.
+ */
+static inline
+void mas_set_range(struct ma_state *mas, unsigned long start, unsigned long last)
+{
+	       mas->index = start;
+	       mas->last = last;
+	       mas->node = MAS_START;
+}
+
+/**
+ * mas_set() - Set up Maple Tree operation state for a different index.
+ * @mas: Maple Tree operation state.
+ * @index: New index into the Maple Tree.
+ *
+ * Move the operation state to refer to a different index.  This will
+ * have the effect of starting a walk from the top; see mas_next()
+ * to move to an adjacent index.
+ */
+static inline void mas_set(struct ma_state *mas, unsigned long index)
+{
+
+	mas_set_range(mas, index, index);
+}
+
+static inline bool mt_external_lock(const struct maple_tree *mt)
+{
+	return (mt->ma_flags & MT_FLAGS_LOCK_MASK) == MT_FLAGS_LOCK_EXTERN;
+}
+
+/**
+ * mt_init_flags() - Initialise an empty maple tree with flags.
+ * @mt: Maple Tree
+ * @flags: maple tree flags.
+ *
+ * If you need to initialise a Maple Tree with special flags (eg, an
+ * allocation tree), use this function.
+ *
+ * Context: Any context.
+ */
+static inline void mt_init_flags(struct maple_tree *mt, unsigned int flags)
+{
+	mt->ma_flags = flags;
+	if (!mt_external_lock(mt))
+		spin_lock_init(&mt->ma_lock);
+	rcu_assign_pointer(mt->ma_root, NULL);
+}
+
+/**
+ * mt_init() - Initialise an empty maple tree.
+ * @mt: Maple Tree
+ *
+ * An empty Maple Tree.
+ *
+ * Context: Any context.
+ */
+static inline void mt_init(struct maple_tree *mt)
+{
+	mt_init_flags(mt, 0);
+}
+
+static inline bool mt_in_rcu(struct maple_tree *mt)
+{
+#ifdef CONFIG_MAPLE_RCU_DISABLED
+	return false;
+#endif
+	return mt->ma_flags & MT_FLAGS_USE_RCU;
+}
+
+/**
+ * mt_clear_in_rcu() - Switch the tree to non-RCU mode.
+ * @mt: The Maple Tree
+ */
+static inline void mt_clear_in_rcu(struct maple_tree *mt)
+{
+	if (!mt_in_rcu(mt))
+		return;
+
+	if (mt_external_lock(mt)) {
+		BUG_ON(!mt_lock_is_held(mt));
+		mt->ma_flags &= ~MT_FLAGS_USE_RCU;
+	} else {
+		mtree_lock(mt);
+		mt->ma_flags &= ~MT_FLAGS_USE_RCU;
+		mtree_unlock(mt);
+	}
+}
+
+/**
+ * mt_set_in_rcu() - Switch the tree to RCU safe mode.
+ * @mt: The Maple Tree
+ */
+static inline void mt_set_in_rcu(struct maple_tree *mt)
+{
+	if (mt_in_rcu(mt))
+		return;
+
+	if (mt_external_lock(mt)) {
+		BUG_ON(!mt_lock_is_held(mt));
+		mt->ma_flags |= MT_FLAGS_USE_RCU;
+	} else {
+		mtree_lock(mt);
+		mt->ma_flags |= MT_FLAGS_USE_RCU;
+		mtree_unlock(mt);
+	}
+}
+
+void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max);
+void *mt_find_after(struct maple_tree *mt, unsigned long *index,
+		    unsigned long max);
+void *mt_prev(struct maple_tree *mt, unsigned long index,  unsigned long min);
+void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max);
+
+/**
+ * mt_for_each - Iterate over each entry starting at index until max.
+ * @__tree: The Maple Tree
+ * @__entry: The current entry
+ * @__index: The index to update to track the location in the tree
+ * @__max: The maximum limit for @index
+ *
+ * Note: Will not return the zero entry.
+ */
+#define mt_for_each(__tree, __entry, __index, __max) \
+	for (__entry = mt_find(__tree, &(__index), __max); \
+		__entry; __entry = mt_find_after(__tree, &(__index), __max))
+
+
+#ifdef CONFIG_DEBUG_MAPLE_TREE
+extern atomic_t maple_tree_tests_run;
+extern atomic_t maple_tree_tests_passed;
+
+void mt_dump(const struct maple_tree *mt);
+void mt_validate(struct maple_tree *mt);
+#define MT_BUG_ON(__tree, __x) do {					\
+	atomic_inc(&maple_tree_tests_run);				\
+	if (__x) {							\
+		pr_info("BUG at %s:%d (%u)\n",				\
+		__func__, __LINE__, __x);				\
+		mt_dump(__tree);					\
+		pr_info("Pass: %u Run:%u\n",				\
+			atomic_read(&maple_tree_tests_passed),		\
+			atomic_read(&maple_tree_tests_run));		\
+		dump_stack();						\
+	} else {							\
+		atomic_inc(&maple_tree_tests_passed);			\
+	}								\
+} while (0)
+#else
+#define MT_BUG_ON(__tree, __x) BUG_ON(__x)
+#endif /* CONFIG_DEBUG_MAPLE_TREE */
+
+#endif /*_LINUX_MAPLE_TREE_H */

include/trace/events/maple_tree.h

@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM maple_tree
+
+#if !defined(_TRACE_MM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_MM_H
+
+
+#include <linux/tracepoint.h>
+
+struct ma_state;
+
+TRACE_EVENT(ma_op,
+
+	TP_PROTO(const char *fn, struct ma_state *mas),
+
+	TP_ARGS(fn, mas),
+
+	TP_STRUCT__entry(
+			__field(const char *, fn)
+			__field(unsigned long, min)
+			__field(unsigned long, max)
+			__field(unsigned long, index)
+			__field(unsigned long, last)
+			__field(void *, node)
+	),
+
+	TP_fast_assign(
+			__entry->fn		= fn;
+			__entry->min		= mas->min;
+			__entry->max		= mas->max;
+			__entry->index		= mas->index;
+			__entry->last		= mas->last;
+			__entry->node		= mas->node;
+	),
+
+	TP_printk("%s\tNode: %p (%lu %lu) range: %lu-%lu",
+		  __entry->fn,
+		  (void *) __entry->node,
+		  (unsigned long) __entry->min,
+		  (unsigned long) __entry->max,
+		  (unsigned long) __entry->index,
+		  (unsigned long) __entry->last
+	)
+)
+TRACE_EVENT(ma_read,
+
+	TP_PROTO(const char *fn, struct ma_state *mas),
+
+	TP_ARGS(fn, mas),
+
+	TP_STRUCT__entry(
+			__field(const char *, fn)
+			__field(unsigned long, min)
+			__field(unsigned long, max)
+			__field(unsigned long, index)
+			__field(unsigned long, last)
+			__field(void *, node)
+	),
+
+	TP_fast_assign(
+			__entry->fn		= fn;
+			__entry->min		= mas->min;
+			__entry->max		= mas->max;
+			__entry->index		= mas->index;
+			__entry->last		= mas->last;
+			__entry->node		= mas->node;
+	),
+
+	TP_printk("%s\tNode: %p (%lu %lu) range: %lu-%lu",
+		  __entry->fn,
+		  (void *) __entry->node,
+		  (unsigned long) __entry->min,
+		  (unsigned long) __entry->max,
+		  (unsigned long) __entry->index,
+		  (unsigned long) __entry->last
+	)
+)
+
+TRACE_EVENT(ma_write,
+
+	TP_PROTO(const char *fn, struct ma_state *mas, unsigned long piv,
+		 void *val),
+
+	TP_ARGS(fn, mas, piv, val),
+
+	TP_STRUCT__entry(
+			__field(const char *, fn)
+			__field(unsigned long, min)
+			__field(unsigned long, max)
+			__field(unsigned long, index)
+			__field(unsigned long, last)
+			__field(unsigned long, piv)
+			__field(void *, val)
+			__field(void *, node)
+	),
+
+	TP_fast_assign(
+			__entry->fn		= fn;
+			__entry->min		= mas->min;
+			__entry->max		= mas->max;
+			__entry->index		= mas->index;
+			__entry->last		= mas->last;
+			__entry->piv		= piv;
+			__entry->val		= val;
+			__entry->node		= mas->node;
+	),
+
+	TP_printk("%s\tNode %p (%lu %lu) range:%lu-%lu piv (%lu) val %p",
+		  __entry->fn,
+		  (void *) __entry->node,
+		  (unsigned long) __entry->min,
+		  (unsigned long) __entry->max,
+		  (unsigned long) __entry->index,
+		  (unsigned long) __entry->last,
+		  (unsigned long) __entry->piv,
+		  (void *) __entry->val
+	)
+)
+#endif /* _TRACE_MM_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

init/main.c

@@ -115,6 +115,7 @@ static int kernel_init(void *);
 
 extern void init_IRQ(void);
 extern void radix_tree_init(void);
+extern void maple_tree_init(void);
 
 /*
  * Debug helper: via this flag we know that we are in 'early bootup code'
@@ -1006,6 +1007,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
 		 "Interrupts were enabled *very* early, fixing it\n"))
 		local_irq_disable();
 	radix_tree_init();
+	maple_tree_init();
 
 	/*
 	 * Set up housekeeping before setting up workqueues to allow the unbound

lib/Kconfig.debug

@@ -825,6 +825,13 @@ config DEBUG_VM_VMACACHE
 	  can cause significant overhead, so only enable it in non-production
 	  environments.
 
+config DEBUG_VM_MAPLE_TREE
+	bool "Debug VM maple trees"
+	depends on DEBUG_VM
+	select DEBUG_MAPLE_TREE
+	help
+	  Enable VM maple tree debugging information and extra validations.
+
 	  If unsure, say N.
 
 config DEBUG_VM_RB
@@ -1640,6 +1647,14 @@ config BUG_ON_DATA_CORRUPTION
 
 	  If unsure, say N.
 
+config DEBUG_MAPLE_TREE
+	bool "Debug maple trees"
+	depends on DEBUG_KERNEL
+	help
+	  Enable maple tree debugging information and extra validations.
+
+	  If unsure, say N.
+
 endmenu
 
 config DEBUG_CREDENTIALS

lib/Makefile

@@ -29,7 +29,7 @@ endif
 
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 rbtree.o radix-tree.o timerqueue.o xarray.o \
-	 idr.o extable.o irq_regs.o argv_split.o \
+	 maple_tree.o idr.o extable.o irq_regs.o argv_split.o \
 	 flex_proportions.o ratelimit.o show_mem.o \
 	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
 	 earlycpio.o seq_buf.o siphash.o dec_and_lock.o \

tools/include/linux/slab.h

@@ -41,4 +41,8 @@ struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
 			unsigned int align, unsigned int flags,
 			void (*ctor)(void *));
 
+void kmem_cache_free_bulk(struct kmem_cache *cachep, size_t size, void **list);
+int kmem_cache_alloc_bulk(struct kmem_cache *cachep, gfp_t gfp, size_t size,
+			  void **list);
+
 #endif		/* _TOOLS_SLAB_H */

tools/testing/radix-tree/.gitignore

@@ -6,3 +6,5 @@ main
 multiorder
 radix-tree.c
 xarray
+maple
+ma_xa_benchmark

tools/testing/radix-tree/Makefile

@@ -4,9 +4,9 @@ CFLAGS += -I. -I../../include -g -Og -Wall -D_LGPL_SOURCE -fsanitize=address \
 	  -fsanitize=undefined
 LDFLAGS += -fsanitize=address -fsanitize=undefined
 LDLIBS+= -lpthread -lurcu
-TARGETS = main idr-test multiorder xarray
+TARGETS = main idr-test multiorder xarray maple
 CORE_OFILES := xarray.o radix-tree.o idr.o linux.o test.o find_bit.o bitmap.o \
-			 slab.o
+			 slab.o maple.o
 OFILES = main.o $(CORE_OFILES) regression1.o regression2.o regression3.o \
 	 regression4.o tag_check.o multiorder.o idr-test.o iteration_check.o \
 	 iteration_check_2.o benchmark.o
@@ -29,6 +29,8 @@ idr-test: idr-test.o $(CORE_OFILES)
 
 xarray: $(CORE_OFILES)
 
+maple: $(CORE_OFILES)
+
 multiorder: multiorder.o $(CORE_OFILES)
 
 clean:
@@ -40,6 +42,7 @@ $(OFILES): Makefile *.h */*.h generated/map-shift.h \
 	../../include/linux/*.h \
 	../../include/asm/*.h \
 	../../../include/linux/xarray.h \
+	../../../include/linux/maple_tree.h \
 	../../../include/linux/radix-tree.h \
 	../../../include/linux/idr.h
 
@@ -51,6 +54,8 @@ idr.c: ../../../lib/idr.c
 
 xarray.o: ../../../lib/xarray.c ../../../lib/test_xarray.c
 
+maple.o: ../../../lib/maple_tree.c ../../../lib/test_maple_tree.c
+
 generated/map-shift.h:
 	@if ! grep -qws $(SHIFT) generated/map-shift.h; then		\
 		echo "#define XA_CHUNK_SHIFT $(SHIFT)" >		\

tools/testing/radix-tree/generated/autoconf.h

@@ -1 +1,2 @@
 #define CONFIG_XARRAY_MULTI 1
+#define CONFIG_64BIT 1

tools/testing/radix-tree/linux.c

@@ -23,15 +23,47 @@ struct kmem_cache {
 	int nr_objs;
 	void *objs;
 	void (*ctor)(void *);
+	unsigned int non_kernel;
+	unsigned long nr_allocated;
+	unsigned long nr_tallocated;
 };
 
+void kmem_cache_set_non_kernel(struct kmem_cache *cachep, unsigned int val)
+{
+	cachep->non_kernel = val;
+}
+
+unsigned long kmem_cache_get_alloc(struct kmem_cache *cachep)
+{
+	return cachep->size * cachep->nr_allocated;
+}
+
+unsigned long kmem_cache_nr_allocated(struct kmem_cache *cachep)
+{
+	return cachep->nr_allocated;
+}
+
+unsigned long kmem_cache_nr_tallocated(struct kmem_cache *cachep)
+{
+	return cachep->nr_tallocated;
+}
+
+void kmem_cache_zero_nr_tallocated(struct kmem_cache *cachep)
+{
+	cachep->nr_tallocated = 0;
+}
+
 void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
 		int gfp)
 {
 	void *p;
 
-	if (!(gfp & __GFP_DIRECT_RECLAIM))
-		return NULL;
+	if (!(gfp & __GFP_DIRECT_RECLAIM)) {
+		if (!cachep->non_kernel)
+			return NULL;
+
+		cachep->non_kernel--;
+	}
 
 	pthread_mutex_lock(&cachep->lock);
 	if (cachep->nr_objs) {
@@ -53,19 +85,21 @@ void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
 			memset(p, 0, cachep->size);
 	}
 
+	uatomic_inc(&cachep->nr_allocated);
 	uatomic_inc(&nr_allocated);
+	uatomic_inc(&cachep->nr_tallocated);
 	if (kmalloc_verbose)
 		printf("Allocating %p from slab\n", p);
 	return p;
 }
 
-void kmem_cache_free(struct kmem_cache *cachep, void *objp)
+void kmem_cache_free_locked(struct kmem_cache *cachep, void *objp)
 {
 	assert(objp);
 	uatomic_dec(&nr_allocated);
+	uatomic_dec(&cachep->nr_allocated);
 	if (kmalloc_verbose)
 		printf("Freeing %p to slab\n", objp);
-	pthread_mutex_lock(&cachep->lock);
 	if (cachep->nr_objs > 10 || cachep->align) {
 		memset(objp, POISON_FREE, cachep->size);
 		free(objp);
@@ -75,9 +109,80 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
 		node->parent = cachep->objs;
 		cachep->objs = node;
 	}
+}
+
+void kmem_cache_free(struct kmem_cache *cachep, void *objp)
+{
+	pthread_mutex_lock(&cachep->lock);
+	kmem_cache_free_locked(cachep, objp);
 	pthread_mutex_unlock(&cachep->lock);
 }
 
+void kmem_cache_free_bulk(struct kmem_cache *cachep, size_t size, void **list)
+{
+	if (kmalloc_verbose)
+		pr_debug("Bulk free %p[0-%lu]\n", list, size - 1);
+
+	pthread_mutex_lock(&cachep->lock);
+	for (int i = 0; i < size; i++)
+		kmem_cache_free_locked(cachep, list[i]);
+	pthread_mutex_unlock(&cachep->lock);
+}
+
+int kmem_cache_alloc_bulk(struct kmem_cache *cachep, gfp_t gfp, size_t size,
+			  void **p)
+{
+	size_t i;
+
+	if (kmalloc_verbose)
+		pr_debug("Bulk alloc %lu\n", size);
+
+	if (!(gfp & __GFP_DIRECT_RECLAIM)) {
+		if (cachep->non_kernel < size)
+			return 0;
+
+		cachep->non_kernel -= size;
+	}
+
+	pthread_mutex_lock(&cachep->lock);
+	if (cachep->nr_objs >= size) {
+		struct radix_tree_node *node;
+
+		for (i = 0; i < size; i++) {
+			node = cachep->objs;
+			cachep->nr_objs--;
+			cachep->objs = node->parent;
+			p[i] = node;
+			node->parent = NULL;
+		}
+		pthread_mutex_unlock(&cachep->lock);
+	} else {
+		pthread_mutex_unlock(&cachep->lock);
+		for (i = 0; i < size; i++) {
+			if (cachep->align) {
+				posix_memalign(&p[i], cachep->align,
+					       cachep->size * size);
+			} else {
+				p[i] = malloc(cachep->size * size);
+			}
+			if (cachep->ctor)
+				cachep->ctor(p[i]);
+			else if (gfp & __GFP_ZERO)
+				memset(p[i], 0, cachep->size);
+		}
+	}
+
+	for (i = 0; i < size; i++) {
+		uatomic_inc(&nr_allocated);
+		uatomic_inc(&cachep->nr_allocated);
+		uatomic_inc(&cachep->nr_tallocated);
+		if (kmalloc_verbose)
+			printf("Allocating %p from slab\n", p[i]);
+	}
+
+	return size;
+}
+
 struct kmem_cache *
 kmem_cache_create(const char *name, unsigned int size, unsigned int align,
 		unsigned int flags, void (*ctor)(void *))
@@ -88,7 +193,54 @@ kmem_cache_create(const char *name, unsigned int size, unsigned int align,
 	ret->size = size;
 	ret->align = align;
 	ret->nr_objs = 0;
+	ret->nr_allocated = 0;
+	ret->nr_tallocated = 0;
 	ret->objs = NULL;
 	ret->ctor = ctor;
+	ret->non_kernel = 0;
 	return ret;
 }
+
+/*
+ * Test the test infrastructure for kem_cache_alloc/free and bulk counterparts.
+ */
+void test_kmem_cache_bulk(void)
+{
+	int i;
+	void *list[12];
+	static struct kmem_cache *test_cache, *test_cache2;
+
+	/*
+	 * Testing the bulk allocators without aligned kmem_cache to force the
+	 * bulk alloc/free to reuse
+	 */
+	test_cache = kmem_cache_create("test_cache", 256, 0, SLAB_PANIC, NULL);
+
+	for (i = 0; i < 5; i++)
+		list[i] = kmem_cache_alloc(test_cache, __GFP_DIRECT_RECLAIM);
+
+	for (i = 0; i < 5; i++)
+		kmem_cache_free(test_cache, list[i]);
+	assert(test_cache->nr_objs == 5);
+
+	kmem_cache_alloc_bulk(test_cache, __GFP_DIRECT_RECLAIM, 5, list);
+	kmem_cache_free_bulk(test_cache, 5, list);
+
+	for (i = 0; i < 12 ; i++)
+		list[i] = kmem_cache_alloc(test_cache, __GFP_DIRECT_RECLAIM);
+
+	for (i = 0; i < 12; i++)
+		kmem_cache_free(test_cache, list[i]);
+
+	/* The last free will not be kept around */
+	assert(test_cache->nr_objs == 11);
+
+	/* Aligned caches will immediately free */
+	test_cache2 = kmem_cache_create("test_cache2", 128, 128, SLAB_PANIC, NULL);
+
+	kmem_cache_alloc_bulk(test_cache2, __GFP_DIRECT_RECLAIM, 10, list);
+	kmem_cache_free_bulk(test_cache2, 10, list);
+	assert(!test_cache2->nr_objs);
+
+
+}

tools/testing/radix-tree/linux/kernel.h

@@ -14,6 +14,7 @@
 #include "../../../include/linux/kconfig.h"
 
 #define printk printf
+#define pr_err printk
 #define pr_info printk
 #define pr_debug printk
 #define pr_cont printk

tools/testing/radix-tree/linux/lockdep.h

@@ -11,4 +11,6 @@ static inline void lockdep_set_class(spinlock_t *lock,
 					struct lock_class_key *key)
 {
 }
+
+extern int lockdep_is_held(const void *);
 #endif /* _LINUX_LOCKDEP_H */

tools/testing/radix-tree/linux/maple_tree.h

@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#define atomic_t int32_t
+#include "../../../../include/linux/maple_tree.h"
+#define atomic_inc(x) uatomic_inc(x)
+#define atomic_read(x) uatomic_read(x)
+#define atomic_set(x, y) do {} while (0)
+#define U8_MAX UCHAR_MAX

tools/testing/radix-tree/maple.c

@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * maple_tree.c: Userspace shim for maple tree test-suite
+ * Copyright (c) 2018 Liam R. Howlett <Liam.Howlett@Oracle.com>
+ */
+
+#define CONFIG_DEBUG_MAPLE_TREE
+#define CONFIG_MAPLE_SEARCH
+#include "test.h"
+
+#define module_init(x)
+#define module_exit(x)
+#define MODULE_AUTHOR(x)
+#define MODULE_LICENSE(x)
+#define dump_stack()	assert(0)
+
+#include "../../../lib/maple_tree.c"
+#undef CONFIG_DEBUG_MAPLE_TREE
+#include "../../../lib/test_maple_tree.c"
+
+void farmer_tests(void)
+{
+	struct maple_node *node;
+	DEFINE_MTREE(tree);
+
+	mt_dump(&tree);
+
+	tree.ma_root = xa_mk_value(0);
+	mt_dump(&tree);
+
+	node = mt_alloc_one(GFP_KERNEL);
+	node->parent = (void *)((unsigned long)(&tree) | 1);
+	node->slot[0] = xa_mk_value(0);
+	node->slot[1] = xa_mk_value(1);
+	node->mr64.pivot[0] = 0;
+	node->mr64.pivot[1] = 1;
+	node->mr64.pivot[2] = 0;
+	tree.ma_root = mt_mk_node(node, maple_leaf_64);
+	mt_dump(&tree);
+
+	ma_free_rcu(node);
+}
+
+void maple_tree_tests(void)
+{
+	farmer_tests();
+	maple_tree_seed();
+	maple_tree_harvest();
+}
+
+int __weak main(void)
+{
+	maple_tree_init();
+	maple_tree_tests();
+	rcu_barrier();
+	if (nr_allocated)
+		printf("nr_allocated = %d\n", nr_allocated);
+	return 0;
+}

tools/testing/radix-tree/trace/events/maple_tree.h

@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#define trace_ma_op(a, b) do {} while (0)
+#define trace_ma_read(a, b) do {} while (0)
+#define trace_ma_write(a, b, c, d) do {} while (0)