[dpdk-dev] [PATCH v2 1/2] bitmap: add create bitmap with all bits set

[Suanming Mou <suanmingm@mellanox.com>]

Currently, in the case to use bitmap as resource allocator, after
bitmap creation, all the bitmap bits should be set to indicate the
bit available. Every time when allocate one bit, search for the set
bits and clear it to make it in use.

Add a new rte_bitmap_init_with_all_set() function to have a quick
fill up the bitmap bits.

Comparing with the case create the bitmap as empty and set the bitmap
one by one, the new function costs less cycles.

Signed-off-by: Suanming Mou <suanmingm@mellanox.com>
---
 lib/librte_eal/common/include/rte_bitmap.h | 113 ++++++++++++++++++++++-------
 1 file changed, 85 insertions(+), 28 deletions(-)

diff --git a/lib/librte_eal/common/include/rte_bitmap.h b/lib/librte_eal/common/include/rte_bitmap.h
index 6b846f2..740076b 100644
--- a/lib/librte_eal/common/include/rte_bitmap.h
+++ b/lib/librte_eal/common/include/rte_bitmap.h
@@ -136,6 +136,40 @@ struct rte_bitmap {
 	bmp->go2 = 0;
 }
 
+static inline struct rte_bitmap *
+__rte_bitmap_init(uint32_t n_bits, uint8_t *mem, uint32_t mem_size)
+{
+	struct rte_bitmap *bmp;
+	uint32_t array1_byte_offset, array1_slabs;
+	uint32_t array2_byte_offset, array2_slabs;
+	uint32_t size;
+
+	/* Check input arguments */
+	if (n_bits == 0)
+		return NULL;
+
+	if ((mem == NULL) || (((uintptr_t) mem) & RTE_CACHE_LINE_MASK))
+		return NULL;
+
+	size = __rte_bitmap_get_memory_footprint(n_bits,
+		&array1_byte_offset, &array1_slabs,
+		&array2_byte_offset, &array2_slabs);
+	if (size < mem_size)
+		return NULL;
+
+	/* Setup bitmap */
+	bmp = (struct rte_bitmap *) mem;
+
+	bmp->array1 = (uint64_t *) &mem[array1_byte_offset];
+	bmp->array1_size = array1_slabs;
+	bmp->array2 = (uint64_t *) &mem[array2_byte_offset];
+	bmp->array2_size = array2_slabs;
+
+	__rte_bitmap_scan_init(bmp);
+
+	return bmp;
+}
+
 /**
  * Bitmap memory footprint calculation
  *
@@ -170,36 +204,12 @@ struct rte_bitmap {
 rte_bitmap_init(uint32_t n_bits, uint8_t *mem, uint32_t mem_size)
 {
 	struct rte_bitmap *bmp;
-	uint32_t array1_byte_offset, array1_slabs, array2_byte_offset, array2_slabs;
-	uint32_t size;
 
-	/* Check input arguments */
-	if (n_bits == 0) {
-		return NULL;
-	}
-
-	if ((mem == NULL) || (((uintptr_t) mem) & RTE_CACHE_LINE_MASK)) {
-		return NULL;
-	}
-
-	size = __rte_bitmap_get_memory_footprint(n_bits,
-		&array1_byte_offset, &array1_slabs,
-		&array2_byte_offset, &array2_slabs);
-	if (size < mem_size) {
+	bmp = __rte_bitmap_init(n_bits, mem, mem_size);
+	if (!bmp)
 		return NULL;
-	}
-
-	/* Setup bitmap */
-	memset(mem, 0, size);
-	bmp = (struct rte_bitmap *) mem;
-
-	bmp->array1 = (uint64_t *) &mem[array1_byte_offset];
-	bmp->array1_size = array1_slabs;
-	bmp->array2 = (uint64_t *) &mem[array2_byte_offset];
-	bmp->array2_size = array2_slabs;
-
-	__rte_bitmap_scan_init(bmp);
-
+	memset(bmp->array1, 0, bmp->array1_size * sizeof(uint64_t));
+	memset(bmp->array2, 0, bmp->array2_size * sizeof(uint64_t));
 	return bmp;
 }
 
@@ -483,6 +493,53 @@ struct rte_bitmap {
 	return 0;
 }
 
+/**
+ * Bitmap initialization with all bits set
+ *
+ * @param n_bits
+ *   Number of pre-allocated bits in array2.
+ * @param mem
+ *   Base address of array1 and array2.
+ * @param mem_size
+ *   Minimum expected size of bitmap.
+ * @return
+ *   Handle to bitmap instance.
+ */
+static inline struct rte_bitmap *
+rte_bitmap_init_with_all_set(uint32_t n_bits, uint8_t *mem, uint32_t mem_size)
+{
+	uint32_t i;
+	uint32_t slabs, array1_bits;
+	struct rte_bitmap *bmp;
+
+	bmp = __rte_bitmap_init(n_bits, mem, mem_size);
+	if (!bmp)
+		return NULL;
+
+	array1_bits = bmp->array2_size >> RTE_BITMAP_CL_SLAB_SIZE_LOG2;
+	/* Fill the arry1 slab aligned bits. */
+	slabs = array1_bits >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
+	memset(bmp->array1, 0xff, slabs * sizeof(bmp->array1[0]));
+	/* Clear the array1 left slabs. */
+	memset(&bmp->array1[slabs], 0, (bmp->array1_size - slabs) *
+	       sizeof(bmp->array1[0]));
+	/* Fill the array1 middle not full set slab. */
+	for (i = 0; i < (array1_bits & RTE_BITMAP_SLAB_BIT_MASK); i++)
+		bmp->array1[slabs] |= 1llu << i;
+
+	/* Fill the arry2 slab aligned bits. */
+	slabs = n_bits >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
+	memset(bmp->array2, 0xff, slabs * sizeof(bmp->array2[0]));
+	/* Clear the array2 left slabs. */
+	memset(&bmp->array2[slabs], 0, (bmp->array2_size - slabs) *
+	       sizeof(bmp->array2[0]));
+	/* Fill the array2 middle not full set slab. */
+	for (i = 0; i < (n_bits & RTE_BITMAP_SLAB_BIT_MASK); i++)
+		bmp->array2[slabs] |= 1llu << i;
+
+	return bmp;
+}
+
 #ifdef __cplusplus
 }
 #endif
-- 
1.8.3.1