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ccan
Commits
3d9899b9
Commit
3d9899b9
authored
Jul 29, 2010
by
Rusty Russell
Browse files
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alloc: speed up tiny allocator
parent
27ae4a22
Changes
1
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Showing
1 changed file
with
120 additions
and
53 deletions
+120
-53
ccan/alloc/tiny.c
ccan/alloc/tiny.c
+120
-53
No files found.
ccan/alloc/tiny.c
View file @
3d9899b9
...
@@ -14,6 +14,8 @@
...
@@ -14,6 +14,8 @@
/* Bit 5 (of first byte) == "is this block free?" */
/* Bit 5 (of first byte) == "is this block free?" */
#define FREE_BIT 0x20
#define FREE_BIT 0x20
#define MAX_FREE_CACHED_SIZE 256
/* Val is usually offset by MIN_BLOCK_SIZE here. */
/* Val is usually offset by MIN_BLOCK_SIZE here. */
static
unsigned
encode_length
(
unsigned
long
val
)
static
unsigned
encode_length
(
unsigned
long
val
)
{
{
...
@@ -95,12 +97,30 @@ static unsigned decode(unsigned long *len, bool *free, const unsigned char *arr)
...
@@ -95,12 +97,30 @@ static unsigned decode(unsigned long *len, bool *free, const unsigned char *arr)
return
hdrlen
;
return
hdrlen
;
}
}
/* We keep a
recently-freed array
, one byte per k. */
/* We keep a
helper array for freed mem
, one byte per k. */
static
unsigned
long
free_array_size
(
unsigned
long
poolsize
)
static
unsigned
long
free_array_size
(
unsigned
long
poolsize
)
{
{
return
poolsize
/
1024
;
return
poolsize
/
1024
;
}
}
/* We have series of 69 free sizes like so:
* 1, 2, 3, 4. 6, 8, 10, 12, 14, 16. 20, 24, 28, 32... 252.
*/
static
unsigned
long
free_array_off
(
unsigned
long
size
)
{
unsigned
long
off
;
if
(
size
<=
4
)
off
=
size
-
1
;
else
if
(
size
<=
16
)
off
=
size
/
2
+
1
;
else
off
=
size
/
4
+
5
;
off
*=
3
;
return
off
;
}
void
tiny_alloc_init
(
void
*
pool
,
unsigned
long
poolsize
)
void
tiny_alloc_init
(
void
*
pool
,
unsigned
long
poolsize
)
{
{
/* We start with free array, and then the rest is free. */
/* We start with free array, and then the rest is free. */
...
@@ -124,16 +144,18 @@ static bool try_coalesce(unsigned char *pool, unsigned long poolsize)
...
@@ -124,16 +144,18 @@ static bool try_coalesce(unsigned char *pool, unsigned long poolsize)
do
{
do
{
hdrlen
=
decode
(
&
len
,
&
free
,
pool
+
off
);
hdrlen
=
decode
(
&
len
,
&
free
,
pool
+
off
);
if
(
free
&&
prev_free
)
{
if
(
free
&&
prev_free
)
{
encode
(
prev_len
+
len
,
true
,
pool
+
prev_off
);
prev_len
+=
len
;
encode
(
prev_len
,
true
,
pool
+
prev_off
);
coalesced
=
true
;
coalesced
=
true
;
}
else
{
prev_free
=
free
;
prev_off
=
off
;
prev_len
=
len
;
}
}
prev_free
=
free
;
prev_off
=
off
;
prev_len
=
len
;
off
+=
len
;
off
+=
len
;
}
while
(
off
<
poolsize
);
}
while
(
off
<
poolsize
);
/*
FIXME: Refill free_array here
. */
/*
Clear the free array
. */
if
(
coalesced
)
if
(
coalesced
)
memset
(
pool
,
0
,
free_array_size
(
poolsize
));
memset
(
pool
,
0
,
free_array_size
(
poolsize
));
...
@@ -150,24 +172,36 @@ static bool long_enough(unsigned long offset, unsigned long len,
...
@@ -150,24 +172,36 @@ static bool long_enough(unsigned long offset, unsigned long len,
return
offset
+
size
<=
end
;
return
offset
+
size
<=
end
;
}
}
static
unsigned
long
find_free_end
(
unsigned
char
*
arr
,
unsigned
long
arrsize
)
static
void
add_to_free_array
(
unsigned
char
*
arr
,
unsigned
long
poolsize
,
unsigned
long
size
,
unsigned
long
off
)
{
{
long
i
;
unsigned
long
fa_off
;
if
(
size
>=
MAX_FREE_CACHED_SIZE
)
return
;
for
(
i
=
arrsize
-
1
;
i
>=
0
;
i
--
)
{
for
(
fa_off
=
free_array_off
(
size
);
if
(
arr
[
i
])
fa_off
+
3
<
free_array_size
(
poolsize
);
return
i
+
1
;
fa_off
+=
free_array_off
(
MAX_FREE_CACHED_SIZE
))
{
if
(
!
arr
[
fa_off
]
&&
!
arr
[
fa_off
+
1
]
&&
!
arr
[
fa_off
+
2
])
{
arr
[
fa_off
]
=
(
off
>>
16
);
arr
[
fa_off
+
1
]
=
(
off
>>
8
);
arr
[
fa_off
+
2
]
=
off
;
break
;
}
}
}
return
0
;
}
}
void
*
tiny_alloc_get
(
void
*
pool
,
unsigned
long
poolsize
,
void
*
tiny_alloc_get
(
void
*
pool
,
unsigned
long
poolsize
,
unsigned
long
size
,
unsigned
long
align
)
unsigned
long
size
,
unsigned
long
align
)
{
{
unsigned
long
arrsize
=
free_array_size
(
poolsize
);
unsigned
long
arrsize
=
free_array_size
(
poolsize
);
unsigned
long
len
,
off
,
fa_off
,
fa_hdrlen
,
actual
,
hdr
,
hdrlen
,
freelen
;
unsigned
long
len
,
off
,
actual
,
hdr
,
hdrlen
,
free_bucket
;
long
fa_off
;
unsigned
char
*
arr
=
pool
;
unsigned
char
*
arr
=
pool
;
bool
free
;
bool
free
,
coalesced
=
false
;
/* We can't do anything with tiny pools. */
/* We can't do anything with tiny pools. */
if
(
poolsize
<
MIN_BLOCK_SIZE
)
if
(
poolsize
<
MIN_BLOCK_SIZE
)
...
@@ -177,18 +211,25 @@ void *tiny_alloc_get(void *pool, unsigned long poolsize,
...
@@ -177,18 +211,25 @@ void *tiny_alloc_get(void *pool, unsigned long poolsize,
if
(
!
size
)
if
(
!
size
)
size
=
1
;
size
=
1
;
/* Look for entries in free array. */
/* Look for entries in free array, starting from right size up. */
freelen
=
find_free_end
(
pool
,
arrsize
);
for
(
free_bucket
=
free_array_off
(
size
);
for
(
fa_off
=
0
;
fa_off
<
freelen
;
fa_off
+=
fa_hdrlen
)
{
free_bucket
<
free_array_off
(
MAX_FREE_CACHED_SIZE
);
fa_hdrlen
=
decode
(
&
off
,
&
free
,
arr
+
fa_off
);
free_bucket
+=
3
)
{
off
-=
MIN_BLOCK_SIZE
;
for
(
fa_off
=
free_bucket
;
hdrlen
=
decode
(
&
len
,
&
free
,
arr
+
off
);
fa_off
+
3
<
free_array_size
(
poolsize
);
if
(
long_enough
(
off
,
len
,
size
,
align
))
{
fa_off
+=
free_array_off
(
MAX_FREE_CACHED_SIZE
))
{
/* Move every successive entry down. */
off
=
((
unsigned
long
)
arr
[
fa_off
])
<<
16
memmove
(
arr
+
fa_off
,
arr
+
fa_off
+
fa_hdrlen
,
|
((
unsigned
long
)
arr
[
fa_off
+
1
])
<<
8
freelen
-
(
fa_off
+
fa_hdrlen
));
|
((
unsigned
long
)
arr
[
fa_off
+
2
]);
memset
(
arr
+
freelen
-
fa_hdrlen
,
0
,
fa_hdrlen
);
if
(
!
off
)
goto
found
;
continue
;
hdrlen
=
decode
(
&
len
,
&
free
,
arr
+
off
);
if
(
long_enough
(
off
,
len
,
size
,
align
))
{
/* Remove it. */
memset
(
&
arr
[
fa_off
],
0
,
3
);
goto
found
;
}
}
}
}
}
...
@@ -197,13 +238,17 @@ again:
...
@@ -197,13 +238,17 @@ again:
hdrlen
=
decode
(
&
len
,
&
free
,
arr
+
off
);
hdrlen
=
decode
(
&
len
,
&
free
,
arr
+
off
);
while
(
!
free
||
!
long_enough
(
off
,
len
,
size
,
align
))
{
while
(
!
free
||
!
long_enough
(
off
,
len
,
size
,
align
))
{
/* FIXME: Refill free array if this block is free. */
/* Refill free array as we go. */
if
(
free
&&
coalesced
)
add_to_free_array
(
arr
,
poolsize
,
len
,
off
);
/* Hit end? */
off
+=
len
;
off
+=
len
;
/* Hit end? */
if
(
off
==
poolsize
)
{
if
(
off
==
poolsize
)
{
if
(
try_coalesce
(
pool
,
poolsize
))
if
(
!
coalesced
&&
try_coalesce
(
pool
,
poolsize
))
{
coalesced
=
true
;
goto
again
;
goto
again
;
}
return
NULL
;
return
NULL
;
}
}
hdrlen
=
decode
(
&
len
,
&
free
,
arr
+
off
);
hdrlen
=
decode
(
&
len
,
&
free
,
arr
+
off
);
...
@@ -214,9 +259,11 @@ found:
...
@@ -214,9 +259,11 @@ found:
actual
=
((
off
+
len
-
size
)
&
~
(
align
-
1
));
actual
=
((
off
+
len
-
size
)
&
~
(
align
-
1
));
hdr
=
actual
-
encode_len_with_header
(
off
+
len
-
actual
);
hdr
=
actual
-
encode_len_with_header
(
off
+
len
-
actual
);
/* Do we have enough room to split? */
/* Do we have enough room to split? */
if
(
hdr
-
off
>=
MIN_BLOCK_SIZE
)
{
if
(
hdr
-
off
>=
MIN_BLOCK_SIZE
)
{
encode
(
hdr
-
off
,
true
,
arr
+
off
);
encode
(
hdr
-
off
,
true
,
arr
+
off
);
add_to_free_array
(
arr
,
poolsize
,
hdr
-
off
,
off
);
}
else
{
}
else
{
hdr
=
off
;
hdr
=
off
;
}
}
...
@@ -248,23 +295,23 @@ static unsigned char *to_hdr(void *p)
...
@@ -248,23 +295,23 @@ static unsigned char *to_hdr(void *p)
void
tiny_alloc_free
(
void
*
pool
,
unsigned
long
poolsize
,
void
*
freep
)
void
tiny_alloc_free
(
void
*
pool
,
unsigned
long
poolsize
,
void
*
freep
)
{
{
unsigned
long
len
,
end
,
arrsize
=
free_array_size
(
poolsize
)
;
unsigned
long
len
;
unsigned
char
*
arr
=
pool
;
unsigned
char
*
arr
=
pool
;
unsigned
char
*
hdr
;
unsigned
char
*
hdr
;
bool
free
;
/* Too small to do anything. */
/* Too small to do anything. */
if
(
poolsize
<
MIN_BLOCK_SIZE
)
if
(
poolsize
<
MIN_BLOCK_SIZE
)
return
;
return
;
hdr
=
to_hdr
(
freep
);
hdr
=
to_hdr
(
freep
);
hdr
[
0
]
|=
FREE_BIT
;
end
=
find_free_end
(
pool
,
arrsize
);
decode
(
&
len
,
&
free
,
hdr
);
assert
(
!
free
);
hdr
[
0
]
|=
FREE_BIT
;
/* If we can fit this block, encode it. */
/* If an empty slot, put this in free array. */
len
=
encode_length
(
hdr
-
arr
);
add_to_free_array
(
pool
,
poolsize
,
len
,
hdr
-
arr
);
if
(
end
+
len
<=
arrsize
)
encode
(
hdr
-
arr
+
MIN_BLOCK_SIZE
,
true
,
arr
+
end
);
}
}
unsigned
long
tiny_alloc_size
(
void
*
pool
,
unsigned
long
poolsize
,
void
*
p
)
unsigned
long
tiny_alloc_size
(
void
*
pool
,
unsigned
long
poolsize
,
void
*
p
)
...
@@ -304,29 +351,23 @@ bool tiny_alloc_check(void *pool, unsigned long poolsize)
...
@@ -304,29 +351,23 @@ bool tiny_alloc_check(void *pool, unsigned long poolsize)
{
{
unsigned
long
arrsize
=
free_array_size
(
poolsize
);
unsigned
long
arrsize
=
free_array_size
(
poolsize
);
unsigned
char
*
arr
=
pool
;
unsigned
char
*
arr
=
pool
;
unsigned
long
len
,
off
,
off2
,
hdrlen
,
end
;
unsigned
long
len
,
off
,
hdrlen
;
unsigned
long
i
,
freearr
[
arrsize
],
num_freearr
=
0
;
unsigned
long
i
,
freearr
[
arrsize
],
num_freearr
=
0
;
bool
free
;
bool
free
;
if
(
poolsize
<
MIN_BLOCK_SIZE
)
if
(
poolsize
<
MIN_BLOCK_SIZE
)
return
true
;
return
true
;
end
=
find_free_end
(
pool
,
arrsize
);
for
(
i
=
0
;
i
+
3
<
free_array_size
(
poolsize
);
i
+=
3
)
{
for
(
off
=
0
;
off
<
end
;
off
+=
hdrlen
)
{
off
=
((
unsigned
long
)
arr
[
i
])
<<
16
if
(
!
check_decode
(
arr
+
off
,
end
-
off
))
|
((
unsigned
long
)
arr
[
i
+
1
])
<<
8
return
false
;
|
((
unsigned
long
)
arr
[
i
+
2
]);
hdrlen
=
decode
(
&
off2
,
&
free
,
arr
+
off
);
if
(
!
off
)
off2
-=
MIN_BLOCK_SIZE
;
continue
;
if
(
off2
>=
poolsize
)
return
tiny_check_fail
();
if
(
off
>=
poolsize
)
if
(
!
free
)
return
tiny_check_fail
();
freearr
[
num_freearr
++
]
=
off2
;
}
/* Rest of free array should be all zeroes. */
for
(
off
=
end
;
off
<
arrsize
;
off
++
)
{
if
(
arr
[
off
]
!=
0
)
return
tiny_check_fail
();
return
tiny_check_fail
();
freearr
[
num_freearr
++
]
=
off
;
}
}
for
(
off
=
arrsize
;
off
<
poolsize
;
off
+=
len
)
{
for
(
off
=
arrsize
;
off
<
poolsize
;
off
+=
len
)
{
...
@@ -353,7 +394,33 @@ bool tiny_alloc_check(void *pool, unsigned long poolsize)
...
@@ -353,7 +394,33 @@ bool tiny_alloc_check(void *pool, unsigned long poolsize)
/* Now we should have found everything in freearr. */
/* Now we should have found everything in freearr. */
if
(
num_freearr
)
if
(
num_freearr
)
return
tiny_check_fail
();
return
tiny_check_fail
();
/* Now check that sizes are correct. */
for
(
i
=
0
;
i
+
3
<
free_array_size
(
poolsize
);
i
+=
3
)
{
unsigned
long
fa_off
;
off
=
((
unsigned
long
)
arr
[
i
])
<<
16
|
((
unsigned
long
)
arr
[
i
+
1
])
<<
8
|
((
unsigned
long
)
arr
[
i
+
2
]);
if
(
!
off
)
continue
;
decode
(
&
len
,
&
free
,
arr
+
off
);
/* Would we expect to find this length in this bucket? */
if
(
len
>=
MAX_FREE_CACHED_SIZE
)
return
tiny_check_fail
();
for
(
fa_off
=
free_array_off
(
len
);
fa_off
+
3
<
free_array_size
(
poolsize
);
fa_off
+=
free_array_off
(
MAX_FREE_CACHED_SIZE
))
{
if
(
fa_off
==
i
)
break
;
}
if
(
fa_off
!=
i
)
return
tiny_check_fail
();
}
return
true
;
return
true
;
}
}
...
...
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