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pool.h File Reference

Fixed length block allocator. More...

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Data Structures

struct  pool_header_t
 

Macros

#define pool_aligned_header_bytes   vec_aligned_header_bytes (sizeof (pool_header_t), sizeof (void *))
 Align pool header so that pointers are naturally aligned. More...
 
#define pool_validate_index(v, i)
 
#define pool_len(p)   vec_len(p)
 Number of elements in pool vector. More...
 
#define pool_bytes(P)   (vec_bytes (P) + pool_header_bytes (P))
 Memory usage of pool. More...
 
#define pool_get_aligned(P, E, A)
 Allocate an object E from a pool P (general version). More...
 
#define pool_get(P, E)   pool_get_aligned(P,E,0)
 Allocate an object E from a pool P (unspecified alignment). More...
 
#define pool_is_free(P, E)
 Use free bitmap to query whether given element is free. More...
 
#define pool_is_free_index(P, I)   pool_is_free((P),(P)+(I))
 Use free bitmap to query whether given index is free. More...
 
#define pool_put(P, E)
 Free an object E in pool P. More...
 
#define pool_put_index(p, i)
 Free pool element with given index. More...
 
#define pool_alloc_aligned(P, N, A)
 Allocate N more free elements to pool (general version). More...
 
#define pool_alloc(P, N)   pool_alloc_aligned(P,N,0)
 Allocate N more free elements to pool (unspecified alignment). More...
 
#define pool_free(p)   (p) = _pool_free(p)
 Free a pool. More...
 
#define pool_foreach_region(LO, HI, POOL, BODY)
 Optimized iteration through pool. More...
 
#define pool_foreach(VAR, POOL, BODY)
 Iterate through pool. More...
 
#define pool_elt_at_index(p, i)
 Returns pointer to element at given index. More...
 
#define pool_next_index(P, I)
 Return next occupied pool index after i, useful for safe iteration. More...
 
#define pool_foreach_index(i, v, body)
 Iterate pool by index. More...
 

Functions

static pool_header_t * pool_header (void *v)
 Get pool header from user pool pointer. More...
 
static void pool_validate (void *v)
 Validate a pool. More...
 
static void pool_header_validate_index (void *v, uword index)
 
static uword pool_elts (void *v)
 Number of active elements in a pool. More...
 
static uword pool_header_bytes (void *v)
 Memory usage of pool header. More...
 
static uword pool_free_elts (void *v)
 Queries whether pool has at least N_FREE free elements. More...
 

Detailed Description

Fixed length block allocator.

Pools are built from clib vectors and bitmaps. Use pools when repeatedly allocating and freeing fixed-size data. Pools are fast, and avoid memory fragmentation.

Definition in file pool.h.

Macro Definition Documentation

#define pool_aligned_header_bytes   vec_aligned_header_bytes (sizeof (pool_header_t), sizeof (void *))

Align pool header so that pointers are naturally aligned.

Definition at line 62 of file pool.h.

#define pool_alloc (   P,
  N 
)    pool_alloc_aligned(P,N,0)

Allocate N more free elements to pool (unspecified alignment).

Definition at line 247 of file pool.h.

#define pool_alloc_aligned (   P,
  N,
  A 
)
Value:
do { \
pool_header_t * _p; \
(P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
pool_aligned_header_bytes, \
(A)); \
_p = pool_header (P); \
vec_resize (_p->free_indices, (N)); \
_vec_len (_p->free_indices) -= (N); \
} while (0)
vec_resize
#define vec_resize(V, N)
Resize a vector (no header, unspecified alignment) Add N elements to end of given vector V...
Definition: vec.h:201
pool_header
static pool_header_t * pool_header(void *v)
Get pool header from user pool pointer.
Definition: pool.h:67
pool_aligned_header_bytes
#define pool_aligned_header_bytes
Align pool header so that pointers are naturally aligned.
Definition: pool.h:62
vec_len
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
Definition: vec_bootstrap.h:142

Allocate N more free elements to pool (general version).

Definition at line 235 of file pool.h.

#define pool_bytes (   P)    (vec_bytes (P) + pool_header_bytes (P))

Memory usage of pool.

Definition at line 142 of file pool.h.

#define pool_elt_at_index (   p,
  i 
)
Value:
({ \
typeof (p) _e = (p) + (i); \
ASSERT (! pool_is_free (p, _e)); \
_e; \
})
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Definition: vector_sse2.h:343
pool_is_free
#define pool_is_free(P, E)
Use free bitmap to query whether given element is free.
Definition: pool.h:203
ASSERT
#define ASSERT(truth)
Definition: error_bootstrap.h:69

Returns pointer to element at given index.

ASSERTs that the supplied index is valid. Even though one can write correct code of the form

1 p = pool_base + index;

use of pool_elt_at_index is strongly suggested.

Definition at line 369 of file pool.h.

#define pool_foreach (   VAR,
  POOL,
  BODY 
)
Value:
do { \
uword _pool_foreach_lo, _pool_foreach_hi; \
pool_foreach_region (_pool_foreach_lo, _pool_foreach_hi, (POOL), \
({ \
for ((VAR) = (POOL) + _pool_foreach_lo; \
(VAR) < (POOL) + _pool_foreach_hi; \
(VAR)++) \
do { BODY; } while (0); \
})); \
} while (0)
pool_foreach_region
#define pool_foreach_region(LO, HI, POOL, BODY)
Optimized iteration through pool.
Definition: pool.h:275
uword
u64 uword
Definition: types.h:112

Iterate through pool.

Parameters
VARA variable of same type as pool vector to be used as an iterator.
POOLThe pool to iterate across.
BODYThe operation to perform, typically a code block. See the example below.

This macro will call BODY with each active pool element.

It is a bad idea to allocate or free pool element from within pool_foreach. Build a vector of indices and dispose of them later.

Example
proc_t *procs; // a pool of processes.
proc_t *proc; // pointer to one process; used as the iterator.
pool_foreach (proc, procs, ({
if (proc->state != PROC_STATE_RUNNING)
continue;
// check a running proc in some way
...
}));
Warning
Because pool_foreach is a macro, syntax errors can be difficult to find inside BODY, let alone actual code bugs. One can temporarily split a complex pool_foreach into a trivial pool_foreach which builds a vector of active indices, and a vec_foreach() (or plain for-loop) to walk the active index vector.

Definition at line 348 of file pool.h.

#define pool_foreach_index (   i,
  v,
  body 
)
Value:
for ((i) = 0; (i) < vec_len (v); (i)++) \
{ \
if (! pool_is_free_index ((v), (i))) \
do { body; } while (0); \
}
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Definition: vector_sse2.h:343
v
#define v
Definition: acl.c:314
pool_is_free_index
#define pool_is_free_index(P, I)
Use free bitmap to query whether given index is free.
Definition: pool.h:211
vec_len
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
Definition: vec_bootstrap.h:142

Iterate pool by index.

Definition at line 390 of file pool.h.

#define pool_foreach_region (   LO,
  HI,
  POOL,
  BODY 
)
Value:
do { \
uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
uword _pool_var (bl), * _pool_var (b); \
pool_header_t * _pool_var (p); \
\
_pool_var (p) = pool_header (POOL); \
_pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
_pool_var (bl) = vec_len (_pool_var (b)); \
_pool_var (len) = vec_len (POOL); \
_pool_var (lo) = 0; \
\
for (_pool_var (i) = 0; \
_pool_var (i) <= _pool_var (bl); \
_pool_var (i)++) \
{ \
uword _pool_var (m), _pool_var (f); \
_pool_var (m) = (_pool_var (i) < _pool_var (bl) \
? _pool_var (b) [_pool_var (i)] \
: 1); \
while (_pool_var (m) != 0) \
{ \
_pool_var (f) = first_set (_pool_var (m)); \
_pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
+ min_log2 (_pool_var (f))); \
_pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
? _pool_var (hi) : _pool_var (len)); \
_pool_var (m) ^= _pool_var (f); \
if (_pool_var (hi) > _pool_var (lo)) \
{ \
(LO) = _pool_var (lo); \
(HI) = _pool_var (hi); \
do { BODY; } while (0); \
} \
_pool_var (lo) = _pool_var (hi) + 1; \
} \
} \
} while (0)
hi
vmrglw vmrglh hi
Definition: vector_altivec.h:119
i
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Definition: vector_sse2.h:343
min_log2
static uword min_log2(uword x)
Definition: clib.h:183
pool_header
static pool_header_t * pool_header(void *v)
Get pool header from user pool pointer.
Definition: pool.h:67
lo
lo
Definition: vector_altivec.h:115
first_set
static uword first_set(uword x)
Definition: clib.h:284
uword
u64 uword
Definition: types.h:112
vec_len
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
Definition: vec_bootstrap.h:142
BITS
#define BITS(x)
Definition: clib.h:58

Optimized iteration through pool.

Parameters
LOpointer to first element in chunk
HIpointer to last element in chunk
POOLpool to iterate across
BODYoperation to perform

Optimized version which assumes that BODY is smart enough to process multiple (LOW,HI) chunks. See also pool_foreach().

Definition at line 275 of file pool.h.

#define pool_free (   p)    (p) = _pool_free(p)

Free a pool.

Definition at line 263 of file pool.h.

#define pool_get (   P,
  E 
)    pool_get_aligned(P,E,0)

Allocate an object E from a pool P (unspecified alignment).

Definition at line 200 of file pool.h.

#define pool_get_aligned (   P,
  E,
  A 
)
Value:
do { \
pool_header_t * _pool_var (p) = pool_header (P); \
uword _pool_var (l); \
\
_pool_var (l) = 0; \
if (P) \
_pool_var (l) = vec_len (_pool_var (p)->free_indices); \
\
if (_pool_var (l) > 0) \
{ \
/* Return free element from free list. */ \
uword _pool_var (i) = _pool_var (p)->free_indices[_pool_var (l) - 1]; \
(E) = (P) + _pool_var (i); \
_pool_var (p)->free_bitmap = \
clib_bitmap_andnoti (_pool_var (p)->free_bitmap, _pool_var (i)); \
_vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1; \
} \
else \
{ \
/* Nothing on free list, make a new element and return it. */ \
P = _vec_resize (P, \
/* length_increment */ 1, \
/* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
pool_aligned_header_bytes, \
/* align */ (A)); \
E = vec_end (P) - 1; \
} \
} while (0)
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Definition: vector_sse2.h:343
vec_end
#define vec_end(v)
End (last data address) of vector.
Definition: vec_bootstrap.h:168
pool_header
static pool_header_t * pool_header(void *v)
Get pool header from user pool pointer.
Definition: pool.h:67
pool_aligned_header_bytes
#define pool_aligned_header_bytes
Align pool header so that pointers are naturally aligned.
Definition: pool.h:62
uword
u64 uword
Definition: types.h:112
vec_len
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
Definition: vec_bootstrap.h:142

Allocate an object E from a pool P (general version).

First search free list. If nothing is free extend vector of objects.

Definition at line 169 of file pool.h.

#define pool_is_free (   P,
  E 
)
Value:
({ \
pool_header_t * _pool_var (p) = pool_header (P); \
uword _pool_var (i) = (E) - (P); \
(_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
})
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Definition: vector_sse2.h:343
pool_header
static pool_header_t * pool_header(void *v)
Get pool header from user pool pointer.
Definition: pool.h:67
clib_bitmap_get
static uword clib_bitmap_get(uword *ai, uword i)
Gets the ith bit value from a bitmap.
Definition: bitmap.h:197
uword
u64 uword
Definition: types.h:112
vec_len
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
Definition: vec_bootstrap.h:142

Use free bitmap to query whether given element is free.

Definition at line 203 of file pool.h.

#define pool_is_free_index (   P,
  I 
)    pool_is_free((P),(P)+(I))

Use free bitmap to query whether given index is free.

Definition at line 211 of file pool.h.

#define pool_len (   p)    vec_len(p)

Number of elements in pool vector.

Note
You probably want to call pool_elts() instead.

Definition at line 121 of file pool.h.

#define pool_next_index (   P,
  I 
)
Value:
({ \
pool_header_t * _pool_var (p) = pool_header (P); \
uword _pool_var (rv) = (I) + 1; \
\
_pool_var(rv) = \
(_pool_var (rv) < vec_len (P) ? \
clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
: ~0); \
_pool_var(rv); \
})
clib_bitmap_next_clear
static uword clib_bitmap_next_clear(uword *ai, uword i)
Return the next clear bit in a bitmap starting at bit i.
Definition: bitmap.h:659
pool_header
static pool_header_t * pool_header(void *v)
Get pool header from user pool pointer.
Definition: pool.h:67
uword
u64 uword
Definition: types.h:112
vec_len
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
Definition: vec_bootstrap.h:142
I
#define I(b, c, d)
Definition: md5.c:47

Return next occupied pool index after i, useful for safe iteration.

Definition at line 377 of file pool.h.

#define pool_put (   P,
  E 
)
Value:
do { \
pool_header_t * _pool_var (p) = pool_header (P); \
uword _pool_var (l) = (E) - (P); \
ASSERT (vec_is_member (P, E)); \
ASSERT (! pool_is_free (P, E)); \
\
/* Add element to free bitmap and to free list. */ \
_pool_var (p)->free_bitmap = \
clib_bitmap_ori (_pool_var (p)->free_bitmap, _pool_var (l)); \
vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
} while (0)
vec_add1
#define vec_add1(V, E)
Add 1 element to end of vector (unspecified alignment).
Definition: vec.h:482
pool_is_free
#define pool_is_free(P, E)
Use free bitmap to query whether given element is free.
Definition: pool.h:203
pool_header
static pool_header_t * pool_header(void *v)
Get pool header from user pool pointer.
Definition: pool.h:67
ASSERT
#define ASSERT(truth)
Definition: error_bootstrap.h:69
vec_is_member
#define vec_is_member(v, e)
True if given pointer is within given vector.
Definition: vec_bootstrap.h:171
uword
u64 uword
Definition: types.h:112

Free an object E in pool P.

Definition at line 214 of file pool.h.

#define pool_put_index (   p,
  i 
)
Value:
do { \
typeof (p) _e = (p) + (i); \
pool_put (p, _e); \
} while (0)
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Definition: vector_sse2.h:343
pool_put
#define pool_put(P, E)
Free an object E in pool P.
Definition: pool.h:214

Free pool element with given index.

Definition at line 228 of file pool.h.

#define pool_validate_index (   v,
  i 
)
Value:
do { \
uword __pool_validate_index = (i); \
vec_validate_ha ((v), __pool_validate_index, \
pool_aligned_header_bytes, /* align */ 0); \
pool_header_validate_index ((v), __pool_validate_index); \
} while (0)
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Definition: vector_sse2.h:343
pool_header_validate_index
static void pool_header_validate_index(void *v, uword index)
Definition: pool.h:89
v
#define v
Definition: acl.c:314
pool_aligned_header_bytes
#define pool_aligned_header_bytes
Align pool header so that pointers are naturally aligned.
Definition: pool.h:62
vec_validate_ha
#define vec_validate_ha(V, I, H, A)
Make sure vector is long enough for given index (general version).
Definition: vec.h:376
uword
u64 uword
Definition: types.h:112

Definition at line 97 of file pool.h.

Function Documentation

static uword pool_elts ( void *  v)
inlinestatic

Number of active elements in a pool.

Returns
Number of active elements in a pool

Definition at line 109 of file pool.h.

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static uword pool_free_elts ( void *  v)
inlinestatic

Queries whether pool has at least N_FREE free elements.

Definition at line 149 of file pool.h.

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static pool_header_t* pool_header ( void *  v)
inlinestatic

Get pool header from user pool pointer.

Definition at line 67 of file pool.h.

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static uword pool_header_bytes ( void *  v)
inlinestatic

Memory usage of pool header.

Definition at line 131 of file pool.h.

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static void pool_header_validate_index ( void *  v,
uword  index 
)
inlinestatic

Definition at line 89 of file pool.h.

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static void pool_validate ( void *  v)
inlinestatic

Validate a pool.

Definition at line 74 of file pool.h.

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