/* Bits start here. */
};
-#define BITS_PER_PAGE 2
-/* FIXME: Don't use page states for bitblock. It's tacky and confusing. */
-enum page_state
+/* Assumes a is a power of two. */
+static unsigned long align_up(unsigned long x, unsigned long a)
+{
+ return (x + a - 1) & ~(a - 1);
+}
+
+static unsigned long div_up(unsigned long x, unsigned long a)
+{
+ return (x + a - 1) / a;
+}
+
+/* It turns out that we spend a lot of time dealing with bit pairs.
+ * These routines manipulate them.
+ */
+static uint8_t get_bit_pair(const uint8_t *bits, unsigned long index)
+{
+ return bits[index * 2 / CHAR_BIT] >> (index * 2 % CHAR_BIT) & 3;
+}
+
+static void set_bit_pair(uint8_t *bits, unsigned long index, uint8_t val)
+{
+ bits[index * 2 / CHAR_BIT] &= ~(3 << (index * 2 % CHAR_BIT));
+ bits[index * 2 / CHAR_BIT] |= (val << (index * 2 % CHAR_BIT));
+}
+
+/* This is used for page states and subpage allocations */
+enum alloc_state
{
FREE,
TAKEN,
TAKEN_START,
- SUBPAGE,
+ SPECIAL, /* Sub-page allocation for page states. */
};
-/* Assumes a is a power of two. */
-static unsigned long align_up(unsigned long x, unsigned long a)
+/* The types for subpage metadata. */
+enum sub_metadata_type
{
- return (x + a - 1) & ~(a - 1);
+ /* FREE is same as alloc state */
+ BITMAP = 1,
+};
+
+/* Page states are represented by bitpairs, at the start of the pool. */
+#define BITS_PER_PAGE 2
+
+static enum alloc_state get_page_state(const void *pool, unsigned long page)
+{
+ return get_bit_pair(pool, page);
}
-static unsigned long div_up(unsigned long x, unsigned long a)
+static void set_page_state(void *pool, unsigned long page, enum alloc_state s)
{
- return (x + a - 1) / a;
+ set_bit_pair(pool, page, s);
}
/* The offset of metadata for a subpage allocation is found at the end
/* This is the length of metadata in bits. It consists of two bits
* for every BITMAP_GRANULARITY of usable bytes in the page, then two
- * bits for the TAKEN tailer.. */
+ * bits for the tailer.. */
#define BITMAP_METABITLEN \
((div_up(SUBPAGE_METAOFF, BITMAP_GRANULARITY) + 1) * BITS_PER_PAGE)
/* This is the length in bytes. */
#define BITMAP_METALEN (div_up(BITMAP_METABITLEN, CHAR_BIT))
-static enum page_state get_page_state(const uint8_t *bits, unsigned long page)
-{
- return bits[page * 2 / CHAR_BIT] >> (page * 2 % CHAR_BIT) & 3;
-}
-
-static void set_page_state(uint8_t *bits, unsigned long page, enum page_state s)
-{
- bits[page * 2 / CHAR_BIT] &= ~(3 << (page * 2 % CHAR_BIT));
- bits[page * 2 / CHAR_BIT] |= ((uint8_t)s << (page * 2 % CHAR_BIT));
-}
-
static struct metaheader *first_mheader(void *pool, unsigned long poolsize)
{
unsigned int pagestatelen;
free = 0;
/* We allocate from far end, to increase ability to expand metadata. */
for (i = elems - 1; i >= 0; i--) {
- switch (get_page_state(bits, i)) {
+ switch (get_bit_pair(bits, i)) {
case FREE:
if (++free >= want) {
unsigned long j;
continue;
for (j = i+1; j < i + want; j++)
- set_page_state(bits, j, TAKEN);
- set_page_state(bits, i, TAKEN_START);
+ set_bit_pair(bits, j, TAKEN);
+ set_bit_pair(bits, i, TAKEN_START);
return i;
}
break;
- case SUBPAGE:
+ case SPECIAL:
case TAKEN_START:
case TAKEN:
free = 0;
return i;
}
break;
- case SUBPAGE:
+ case SPECIAL:
case TAKEN_START:
case TAKEN:
free = 0;
long i;
/* TAKEN at end means a bitwise alloc. */
- assert(get_page_state(bits, getpagesize()/BITMAP_GRANULARITY - 1)
- == TAKEN);
+ assert(get_bit_pair(bits, getpagesize()/BITMAP_GRANULARITY-1) == TAKEN);
/* Our bits are the same as the page bits. */
i = alloc_from_bitmap(bits, SUBPAGE_METAOFF/BITMAP_GRANULARITY,
/* TAKEN tags end a subpage alloc. */
for (i = mh->metalen * CHAR_BIT / BITS_PER_PAGE - 1; i >= 0; i -= len) {
- switch (get_page_state(meta, i)) {
+ switch (get_bit_pair(meta, i)) {
case FREE:
len = 1;
free++;
return meta + i / (CHAR_BIT / BITS_PER_PAGE);
}
break;
- case TAKEN:
+ case BITMAP:
/* Skip over this allocated part. */
len = BITMAP_METALEN * CHAR_BIT / BITS_PER_PAGE;
free = 0;
/* Look for partial page. */
for (i = 0; i < poolsize / getpagesize(); i++) {
unsigned long ret;
- if (get_page_state(pool, i) != SUBPAGE)
+ if (get_page_state(pool, i) != SPECIAL)
continue;
ret = sub_page_alloc(pool, i, size, align);
return 0;
}
- /* Actually, this is a SUBPAGE page now. */
- set_page_state(pool, i, SUBPAGE);
+ /* Actually, this is a subpage page now. */
+ set_page_state(pool, i, SPECIAL);
/* Set metadata pointer for page. */
set_page_metadata(pool, i, metadata);
for (i = 0; i < poolsize/getpagesize(); i++) {
uint8_t *meta;
unsigned int j;
- if (get_page_state(pool, i) != SUBPAGE)
+ if (get_page_state(pool, i) != SPECIAL)
continue;
meta = get_page_metadata(pool, i);
pagenum = pool_offset(pool, free) / getpagesize();
- if (get_page_state(pool, pagenum) == SUBPAGE)
+ if (get_page_state(pool, pagenum) == SPECIAL)
subpage_free(pool, pagenum, free);
else {
assert((unsigned long)free % getpagesize() == 0);
{
unsigned long *mhoff = metadata_off(pool, page);
unsigned int i;
- enum page_state last_state = FREE;
+ enum alloc_state last_state = FREE;
if (*mhoff + sizeof(struct metaheader) > poolsize)
return false;
return false;
/* Marker at end of subpage allocation is "taken" */
- if (get_page_state((uint8_t *)pool + *mhoff,
- getpagesize()/BITMAP_GRANULARITY - 1) != TAKEN)
+ if (get_bit_pair((uint8_t *)pool + *mhoff,
+ getpagesize()/BITMAP_GRANULARITY - 1) != TAKEN)
return false;
for (i = 0; i < SUBPAGE_METAOFF / BITMAP_GRANULARITY; i++) {
- enum page_state state;
+ enum alloc_state state;
- state = get_page_state((uint8_t *)pool + *mhoff, i);
+ state = get_bit_pair((uint8_t *)pool + *mhoff, i);
switch (state) {
- case SUBPAGE:
+ case SPECIAL:
return false;
case TAKEN:
if (last_state == FREE)
{
unsigned long i;
struct metaheader *mh;
- enum page_state last_state = FREE;
+ enum alloc_state last_state = FREE;
bool was_metadata = false;
if (poolsize < MIN_SIZE)
}
for (i = 0; i < poolsize / getpagesize(); i++) {
- enum page_state state = get_page_state(pool, i);
+ enum alloc_state state = get_page_state(pool, i);
bool is_metadata = is_metadata_page(pool, poolsize,i);
switch (state) {
if (is_metadata != was_metadata)
return false;
break;
- case SUBPAGE:
+ case SPECIAL:
/* Check metadata pointer etc. */
if (!check_subpage(pool, poolsize, i))
return false;
for (i = 0; i < poolsize / getpagesize(); i++) {
uint8_t *meta;
unsigned int j;
- if (get_page_state(pool, i) != SUBPAGE)
+ if (get_page_state(pool, i) != SPECIAL)
continue;
memset(count, 0, sizeof(count));
projects / ccan / blobdiff