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add support for slab metadata count field

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This commit is contained in:
Daniel Micay 2018-11-01 01:00:59 -04:00
parent 834ce67884
commit 4ac2688d76
1 changed files with 19 additions and 0 deletions
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19
malloc.c
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@ -52,11 +52,16 @@ static union {
char padding[PAGE_SIZE];
} ro __attribute__((aligned(PAGE_SIZE)));
#define SLAB_METADATA_COUNT
struct slab_metadata {
u64 bitmap[4];
struct slab_metadata *next;
struct slab_metadata *prev;
u64 canary_value;
#ifdef SLAB_METADATA_COUNT
u16 count;
#endif
};
static const size_t min_align = 16;
@ -238,11 +243,17 @@ static struct slab_metadata *alloc_metadata(struct size_class *c, size_t slab_si
static void set_slot(struct slab_metadata *metadata, size_t index) {
size_t bucket = index / 64;
metadata->bitmap[bucket] |= 1UL << (index - bucket * 64);
#ifdef SLAB_METADATA_COUNT
metadata->count++;
#endif
}
static void clear_slot(struct slab_metadata *metadata, size_t index) {
size_t bucket = index / 64;
metadata->bitmap[bucket] &= ~(1UL << (index - bucket * 64));
#ifdef SLAB_METADATA_COUNT
metadata->count--;
#endif
}
static bool get_slot(struct slab_metadata *metadata, size_t index) {
@ -293,6 +304,9 @@ static size_t get_free_slot(struct random_state *rng, size_t slots, struct slab_
}
static bool has_free_slots(size_t slots, struct slab_metadata *metadata) {
#ifdef SLAB_METADATA_COUNT
return metadata->count < slots;
#else
if (slots <= 64) {
u64 masked = metadata->bitmap[0] | get_mask(slots);
return masked != ~0UL;
@ -305,11 +319,16 @@ static bool has_free_slots(size_t slots, struct slab_metadata *metadata) {
}
u64 masked = metadata->bitmap[3] | get_mask(slots - 192);
return metadata->bitmap[0] != ~0UL || metadata->bitmap[1] != ~0UL || metadata->bitmap[2] != ~0UL || masked != ~0UL;
#endif
}
static bool is_free_slab(struct slab_metadata *metadata) {
#ifdef SLAB_METADATA_COUNT
return !metadata->count;
#else
return !metadata->bitmap[0] && !metadata->bitmap[1] && !metadata->bitmap[2] &&
!metadata->bitmap[3];
#endif
}
static struct slab_metadata *get_metadata(struct size_class *c, void *p) {