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hardened_malloc
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move slab allocator state to a dedicated mapping

pull/65/head
Daniel Micay 2018-10-14 22:06:16 -04:00
parent 1190966846
commit da6fd5b5ef
1 changed files with 18 additions and 9 deletions
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27
malloc.c
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@ -40,6 +40,7 @@ static union {
struct {
void *slab_region_start;
void *slab_region_end;
struct size_class *size_class_metadata;
struct region_allocator *region_allocator;
struct region_metadata *regions[2];
atomic_bool initialized;
@ -122,7 +123,7 @@ static size_t get_slab_size(size_t slots, size_t size) {
// limit on the number of cached empty slabs before attempting purging instead
static const size_t max_empty_slabs_total = 64 * 1024;
static struct size_class {
struct __attribute__((aligned(CACHELINE_SIZE))) size_class {
struct mutex lock;
void *class_region_start;
@ -152,7 +153,7 @@ static struct size_class {
size_t metadata_allocated;
size_t metadata_count;
size_t metadata_count_unguarded;
} __attribute__((aligned(CACHELINE_SIZE))) size_class_metadata[N_SIZE_CLASSES];
};
#define CLASS_REGION_SIZE (128ULL * 1024 * 1024 * 1024)
#define REAL_CLASS_REGION_SIZE (CLASS_REGION_SIZE * 2)
@ -316,7 +317,7 @@ static void set_canary(struct slab_metadata *metadata, void *p, size_t size) {
static inline void *allocate_small(size_t requested_size) {
struct size_info info = get_size_info(requested_size);
size_t size = info.size ? info.size : 16;
struct size_class *c = &size_class_metadata[info.class];
struct size_class *c = &ro.size_class_metadata[info.class];
size_t slots = size_class_slots[info.class];
size_t slab_size = get_slab_size(slots, size);
@ -449,7 +450,7 @@ static void enqueue_free_slab(struct size_class *c, struct slab_metadata *metada
static inline void deallocate_small(void *p, const size_t *expected_size) {
size_t class = slab_size_class(p);
struct size_class *c = &size_class_metadata[class];
struct size_class *c = &ro.size_class_metadata[class];
size_t size = size_classes[class];
if (expected_size && size != *expected_size) {
fatal_error("sized deallocation mismatch (small)");
@ -707,14 +708,14 @@ static void regions_delete(struct region_metadata *region) {
static void full_lock(void) {
mutex_lock(&ro.region_allocator->lock);
for (unsigned class = 0; class < N_SIZE_CLASSES; class++) {
mutex_lock(&size_class_metadata[class].lock);
mutex_lock(&ro.size_class_metadata[class].lock);
}
}
static void full_unlock(void) {
mutex_unlock(&ro.region_allocator->lock);
for (unsigned class = 0; class < N_SIZE_CLASSES; class++) {
mutex_unlock(&size_class_metadata[class].lock);
mutex_unlock(&ro.size_class_metadata[class].lock);
}
}
@ -722,7 +723,7 @@ static void post_fork_child(void) {
mutex_init(&ro.region_allocator->lock);
random_state_init(&ro.region_allocator->rng);
for (unsigned class = 0; class < N_SIZE_CLASSES; class++) {
struct size_class *c = &size_class_metadata[class];
struct size_class *c = &ro.size_class_metadata[class];
mutex_init(&c->lock);
random_state_init(&c->rng);
}
@ -753,6 +754,9 @@ COLD static void init_slow_path(void) {
}
ro.region_allocator = allocate_pages(sizeof(struct region_allocator), PAGE_SIZE, true);
if (ro.region_allocator == NULL) {
fatal_error("failed to allocate region allocator state");
}
struct region_allocator *ra = ro.region_allocator;
mutex_init(&ra->lock);
@ -775,8 +779,13 @@ COLD static void init_slow_path(void) {
}
ro.slab_region_end = (char *)ro.slab_region_start + slab_region_size;
ro.size_class_metadata = allocate_pages(sizeof(struct size_class) * N_SIZE_CLASSES, PAGE_SIZE, true);
if (ro.size_class_metadata == NULL) {
fatal_error("failed to allocate slab allocator state");
}
for (unsigned class = 0; class < N_SIZE_CLASSES; class++) {
struct size_class *c = &size_class_metadata[class];
struct size_class *c = &ro.size_class_metadata[class];
mutex_init(&c->lock);
random_state_init(&c->rng);
@ -1229,7 +1238,7 @@ EXPORT int h_malloc_trim(UNUSED size_t pad) {
// skip zero byte size class since there's nothing to change
for (unsigned class = 1; class < N_SIZE_CLASSES; class++) {
struct size_class *c = &size_class_metadata[class];
struct size_class *c = &ro.size_class_metadata[class];
size_t slab_size = get_slab_size(size_class_slots[class], size_classes[class]);
mutex_lock(&c->lock);