util: add spdk_bit_pool

spdk_bit_pool is a wrapper around spdk_bit_array with the
intentions of providing much better performance for allocating
from a fragmented bit array.  The cost of searching a large bit
array for a cleared bit can become expensive so the spdk_bit_pool
will provide an ability to track extents of recently cleared
bits.

This initial commit does not adding the tracking yet - it is strictly
a wrapper around spdk_bit_array with enough functionality to replace
the use of spdk_bit_pool in SPDK blobstore with equivalent performance.
This will allow us to switch blobstore to use this minimal
wrapper first, and then iteratively improve spdk_bit_pool to provide
the better performance.

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: I95d0d12db47eac73e0641eb7f94fa5df43d42e45
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/3974
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Paul Luse <paul.e.luse@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Broadcom CI

include/spdk/bit_pool.h

@@ -0,0 +1,191 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright (c) Intel Corporation.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** \file
+ * Bit pool data structure
+ */
+
+#ifndef SPDK_BIT_POOL_H
+#define SPDK_BIT_POOL_H
+
+#include "spdk/stdinc.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct spdk_bit_pool;
+struct spdk_bit_array;
+
+/**
+ * Return the number of bits that a bit pool is currently sized to hold.
+ *
+ * \param pool Bit pool to query.
+ *
+ * \return the number of bits.
+ */
+uint32_t spdk_bit_pool_capacity(const struct spdk_bit_pool *pool);
+
+/**
+ * Create a bit pool.
+ *
+ * All bits in the pool will be available for allocation.
+ *
+ * \param num_bits Number of bits that the bit pool is sized to hold.
+ *
+ * \return a pointer to the new bit pool.
+ */
+struct spdk_bit_pool *spdk_bit_pool_create(uint32_t num_bits);
+
+/**
+ * Create a bit pool from an existing spdk_bit_array.
+ *
+ * The starting state of the bit pool will be specified by the state
+ * of the specified spdk_bit_array.
+ *
+ * The new spdk_bit_pool will consume the spdk_bit_array and assumes
+ * responsibility for freeing it.  The caller should not use the
+ * spdk_bit_array after this function returns.
+ *
+ * \param array spdk_bit_array representing the starting state of the new bit pool.
+ *
+ * \return a pointer to the new bit pool, NULL if one could not be created (in which
+ *         case the caller maintains responsibility for the spdk_bit_array)
+ */
+struct spdk_bit_pool *spdk_bit_pool_create_from_array(struct spdk_bit_array *array);
+
+/**
+ * Free a bit pool and set the pointer to NULL.
+ *
+ * \param pool Bit pool to free.
+ */
+void spdk_bit_pool_free(struct spdk_bit_pool **pool);
+
+/**
+ * Create or resize a bit pool.
+ *
+ * To create a new bit pool, pass a pointer to a spdk_bit_pool pointer that is
+ * NULL.
+ *
+ * The bit pool will be sized to hold at least num_bits.
+ *
+ * If num_bits is larger than the previous size of the bit pool,
+ * the new bits will all be available for future allocations.
+ *
+ * \param pool Bit pool to create/resize.
+ * \param num_bits Number of bits that the bit pool is sized to hold.
+ *
+ * \return 0 on success, negative errno on failure.
+ */
+int spdk_bit_pool_resize(struct spdk_bit_pool **pool, uint32_t num_bits);
+
+/**
+ * Return whether the specified bit has been allocated from the bit pool.
+ *
+ * If bit_index is beyond the end of the current size of the bit pool, this
+ * function will return false (i.e. bits beyond the end of the pool cannot be allocated).
+ *
+ * \param pool Bit pool to query.
+ * \param bit_index The index of a bit to query.
+ *
+ * \return true if the bit has been allocated, false otherwise
+ */
+bool spdk_bit_pool_is_allocated(const struct spdk_bit_pool *pool, uint32_t bit_index);
+
+/**
+ * Allocate a bit from the bit pool.
+ *
+ * \param pool Bit pool to allocate a bit from
+ *
+ * \return index of the allocated bit, UINT32_MAX if no free bits exist
+ */
+uint32_t spdk_bit_pool_allocate_bit(struct spdk_bit_pool *pool);
+
+/**
+ * Free a bit back to the bit pool.
+ *
+ * Callers must not try to free a bit that has not been allocated, otherwise the
+ * pool may become corrupted without notification.  Freeing a bit that has not
+ * been allocated will result in an assert in debug builds.
+ *
+ * \param pool Bit pool to place the freed bit
+ * \param bit_index The index of a bit to free.
+ */
+void spdk_bit_pool_free_bit(struct spdk_bit_pool *pool, uint32_t bit_index);
+
+/**
+ * Count the number of bits allocated from the pool.
+ *
+ * \param pool The bit pool to count.
+ *
+ * \return the number of bits allocated from the pool.
+ */
+uint32_t spdk_bit_pool_count_allocated(const struct spdk_bit_pool *pool);
+
+/**
+ * Count the number of free bits in the pool.
+ *
+ * \param pool The bit pool to count.
+ *
+ * \return the number of free bits in the pool.
+ */
+uint32_t spdk_bit_pool_count_free(const struct spdk_bit_pool *pool);
+
+/**
+ * Store bitmask from bit pool.
+ *
+ * \param pool Bit pool.
+ * \param mask Destination mask. Mask and bit array pool must be equal.
+ */
+void spdk_bit_pool_store_mask(const struct spdk_bit_pool *pool, void *mask);
+
+/**
+ * Load bitmask to bit pool.
+ *
+ * \param pool Bit pool.
+ * \param mask Source mask. Mask and bit array pool must be equal.
+ */
+void spdk_bit_pool_load_mask(struct spdk_bit_pool *pool, const void *mask);
+
+/**
+ * Free all bits back into the bit pool.
+ *
+ * \param pool Bit pool.
+ */
+void spdk_bit_pool_free_all_bits(struct spdk_bit_pool *pool);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

lib/util/Makefile

@@ -35,7 +35,7 @@ SPDK_ROOT_DIR := $(abspath $(CURDIR)/../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
 SO_VER := 2
-SO_MINOR := 0
+SO_MINOR := 1
 
 C_SRCS = base64.c bit_array.c cpuset.c crc16.c crc32.c crc32c.c crc32_ieee.c \
 	 dif.c fd.c file.c iov.c math.c pipe.c strerror_tls.c string.c uuid.c

lib/util/bit_array.c

@@ -34,6 +34,7 @@
 #include "spdk/stdinc.h"
 
 #include "spdk/bit_array.h"
+#include "spdk/bit_pool.h"
 #include "spdk/env.h"
 
 #include "spdk/likely.h"
@@ -361,3 +362,160 @@ spdk_bit_array_clear_mask(struct spdk_bit_array *ba)
 		spdk_bit_array_clear(ba, i + size * CHAR_BIT);
 	}
 }
+
+struct spdk_bit_pool {
+	struct spdk_bit_array	*array;
+	uint32_t		lowest_free_bit;
+	uint32_t		free_count;
+};
+
+struct spdk_bit_pool *
+spdk_bit_pool_create(uint32_t num_bits)
+{
+	struct spdk_bit_pool *pool = NULL;
+	struct spdk_bit_array *array;
+
+	array = spdk_bit_array_create(num_bits);
+	if (array == NULL) {
+		return NULL;
+	}
+
+	pool = calloc(1, sizeof(*pool));
+	if (pool == NULL) {
+		spdk_bit_array_free(&array);
+		return NULL;
+	}
+
+	pool->array = array;
+	pool->lowest_free_bit = 0;
+	pool->free_count = num_bits;
+
+	return pool;
+}
+
+struct spdk_bit_pool *
+spdk_bit_pool_create_from_array(struct spdk_bit_array *array)
+{
+	struct spdk_bit_pool *pool = NULL;
+
+	pool = calloc(1, sizeof(*pool));
+	if (pool == NULL) {
+		return NULL;
+	}
+
+	pool->array = array;
+	pool->lowest_free_bit = spdk_bit_array_find_first_clear(array, 0);
+	pool->free_count = spdk_bit_array_count_clear(array);
+
+	return pool;
+}
+
+void
+spdk_bit_pool_free(struct spdk_bit_pool **ppool)
+{
+	struct spdk_bit_pool *pool;
+
+	if (!ppool) {
+		return;
+	}
+
+	pool = *ppool;
+	*ppool = NULL;
+	if (pool != NULL) {
+		spdk_bit_array_free(&pool->array);
+		free(pool);
+	}
+}
+
+int
+spdk_bit_pool_resize(struct spdk_bit_pool **ppool, uint32_t num_bits)
+{
+	struct spdk_bit_pool *pool;
+	int rc;
+
+	assert(ppool != NULL);
+
+	pool = *ppool;
+	rc = spdk_bit_array_resize(&pool->array, num_bits);
+	if (rc) {
+		return rc;
+	}
+
+	pool->lowest_free_bit = spdk_bit_array_find_first_clear(pool->array, 0);
+	pool->free_count = spdk_bit_array_count_clear(pool->array);
+
+	return 0;
+}
+
+uint32_t
+spdk_bit_pool_capacity(const struct spdk_bit_pool *pool)
+{
+	return spdk_bit_array_capacity(pool->array);
+}
+
+bool
+spdk_bit_pool_is_allocated(const struct spdk_bit_pool *pool, uint32_t bit_index)
+{
+	return spdk_bit_array_get(pool->array, bit_index);
+}
+
+uint32_t
+spdk_bit_pool_allocate_bit(struct spdk_bit_pool *pool)
+{
+	uint32_t bit_index = pool->lowest_free_bit;
+
+	if (bit_index == UINT32_MAX) {
+		return UINT32_MAX;
+	}
+
+	spdk_bit_array_set(pool->array, bit_index);
+	pool->lowest_free_bit = spdk_bit_array_find_first_clear(pool->array, bit_index);
+	pool->free_count--;
+	return bit_index;
+}
+
+void
+spdk_bit_pool_free_bit(struct spdk_bit_pool *pool, uint32_t bit_index)
+{
+	assert(spdk_bit_array_get(pool->array, bit_index) == true);
+
+	spdk_bit_array_clear(pool->array, bit_index);
+	if (pool->lowest_free_bit > bit_index) {
+		pool->lowest_free_bit = bit_index;
+	}
+	pool->free_count++;
+}
+
+uint32_t
+spdk_bit_pool_count_allocated(const struct spdk_bit_pool *pool)
+{
+	return spdk_bit_array_capacity(pool->array) - pool->free_count;
+}
+
+uint32_t
+spdk_bit_pool_count_free(const struct spdk_bit_pool *pool)
+{
+	return pool->free_count;
+}
+
+void
+spdk_bit_pool_store_mask(const struct spdk_bit_pool *pool, void *mask)
+{
+	spdk_bit_array_store_mask(pool->array, mask);
+}
+
+void
+spdk_bit_pool_load_mask(struct spdk_bit_pool *pool, const void *mask)
+{
+	spdk_bit_array_load_mask(pool->array, mask);
+	pool->lowest_free_bit = spdk_bit_array_find_first_clear(pool->array, 0);
+	pool->free_count = spdk_bit_array_count_clear(pool->array);
+}
+
+void
+spdk_bit_pool_free_all_bits(struct spdk_bit_pool *pool)
+{
+	spdk_bit_array_clear_mask(pool->array);
+	pool->lowest_free_bit = 0;
+	pool->free_count = spdk_bit_array_capacity(pool->array);
+}

lib/util/spdk_util.map

@@ -23,6 +23,21 @@
 	spdk_bit_array_load_mask;
 	spdk_bit_array_clear_mask;
 
+	# public functions in bit_pool.h
+	spdk_bit_pool_capacity;
+	spdk_bit_pool_create;
+	spdk_bit_pool_create_from_array;
+	spdk_bit_pool_free;
+	spdk_bit_pool_resize;
+	spdk_bit_pool_is_allocated;
+	spdk_bit_pool_allocate_bit;
+	spdk_bit_pool_free_bit;
+	spdk_bit_pool_count_allocated;
+	spdk_bit_pool_count_free;
+	spdk_bit_pool_store_mask;
+	spdk_bit_pool_load_mask;
+	spdk_bit_pool_free_all_bits;
+
 	# public functions in cpuset.h
 	spdk_cpuset_alloc;
 	spdk_cpuset_free;