#include "libc.h"
#include "atomic.h"
#include "pthread_impl.h"
+#include "malloc_impl.h"
#if defined(__GNUC__) && defined(__PIC__)
#define inline inline __attribute__((always_inline))
#endif
-void *__mmap(void *, size_t, int, int, int, off_t);
-int __munmap(void *, size_t);
-void *__mremap(void *, size_t, size_t, int, ...);
-int __madvise(void *, size_t, int);
-
-struct chunk {
- size_t psize, csize;
- struct chunk *next, *prev;
-};
-
-struct bin {
- volatile int lock[2];
- struct chunk *head;
- struct chunk *tail;
-};
-
static struct {
volatile uint64_t binmap;
struct bin bins[64];
- volatile int free_lock[2];
+ volatile int split_merge_lock[2];
} mal;
-
-#define SIZE_ALIGN (4*sizeof(size_t))
-#define SIZE_MASK (-SIZE_ALIGN)
-#define OVERHEAD (2*sizeof(size_t))
-#define MMAP_THRESHOLD (0x1c00*SIZE_ALIGN)
-#define DONTCARE 16
-#define RECLAIM 163840
-
-#define CHUNK_SIZE(c) ((c)->csize & -2)
-#define CHUNK_PSIZE(c) ((c)->psize & -2)
-#define PREV_CHUNK(c) ((struct chunk *)((char *)(c) - CHUNK_PSIZE(c)))
-#define NEXT_CHUNK(c) ((struct chunk *)((char *)(c) + CHUNK_SIZE(c)))
-#define MEM_TO_CHUNK(p) (struct chunk *)((char *)(p) - OVERHEAD)
-#define CHUNK_TO_MEM(c) (void *)((char *)(c) + OVERHEAD)
-#define BIN_TO_CHUNK(i) (MEM_TO_CHUNK(&mal.bins[i].head))
-
-#define C_INUSE ((size_t)1)
-
-#define IS_MMAPPED(c) !((c)->csize & (C_INUSE))
-
+int __malloc_replaced;
/* Synchronization tools */
static inline void lock(volatile int *lk)
{
- if (libc.threads_minus_1)
+ int need_locks = libc.need_locks;
+ if (need_locks) {
while(a_swap(lk, 1)) __wait(lk, lk+1, 1, 1);
+ if (need_locks < 0) libc.need_locks = 0;
+ }
}
static inline void unlock(volatile int *lk)
}
#endif
-void *__expand_heap(size_t *);
-
static struct chunk *expand_heap(size_t n)
{
- static int heap_lock[2];
static void *end;
void *p;
struct chunk *w;
* we need room for an extra zero-sized sentinel chunk. */
n += SIZE_ALIGN;
- lock(heap_lock);
-
p = __expand_heap(&n);
- if (!p) {
- unlock(heap_lock);
- return 0;
- }
+ if (!p) return 0;
/* If not just expanding existing space, we need to make a
* new sentinel chunk below the allocated space. */
w = MEM_TO_CHUNK(p);
w->csize = n | C_INUSE;
- unlock(heap_lock);
-
return w;
}
NEXT_CHUNK(c)->psize |= C_INUSE;
}
-static int alloc_fwd(struct chunk *c)
+static void bin_chunk(struct chunk *self, int i)
{
- int i;
- size_t k;
- while (!((k=c->csize) & C_INUSE)) {
- i = bin_index(k);
- lock_bin(i);
- if (c->csize == k) {
- unbin(c, i);
- unlock_bin(i);
- return 1;
- }
- unlock_bin(i);
- }
- return 0;
-}
-
-static int alloc_rev(struct chunk *c)
-{
- int i;
- size_t k;
- while (!((k=c->psize) & C_INUSE)) {
- i = bin_index(k);
- lock_bin(i);
- if (c->psize == k) {
- unbin(PREV_CHUNK(c), i);
- unlock_bin(i);
- return 1;
- }
- unlock_bin(i);
- }
- return 0;
+ self->next = BIN_TO_CHUNK(i);
+ self->prev = mal.bins[i].tail;
+ self->next->prev = self;
+ self->prev->next = self;
+ if (self->prev == BIN_TO_CHUNK(i))
+ a_or_64(&mal.binmap, 1ULL<<i);
}
-
-/* pretrim - trims a chunk _prior_ to removing it from its bin.
- * Must be called with i as the ideal bin for size n, j the bin
- * for the _free_ chunk self, and bin j locked. */
-static int pretrim(struct chunk *self, size_t n, int i, int j)
+static void trim(struct chunk *self, size_t n)
{
- size_t n1;
+ size_t n1 = CHUNK_SIZE(self);
struct chunk *next, *split;
- /* We cannot pretrim if it would require re-binning. */
- if (j < 40) return 0;
- if (j < i+3) {
- if (j != 63) return 0;
- n1 = CHUNK_SIZE(self);
- if (n1-n <= MMAP_THRESHOLD) return 0;
- } else {
- n1 = CHUNK_SIZE(self);
- }
- if (bin_index(n1-n) != j) return 0;
+ if (n >= n1 - DONTCARE) return;
next = NEXT_CHUNK(self);
split = (void *)((char *)self + n);
- split->prev = self->prev;
- split->next = self->next;
- split->prev->next = split;
- split->next->prev = split;
split->psize = n | C_INUSE;
split->csize = n1-n;
next->psize = n1-n;
self->csize = n | C_INUSE;
- return 1;
-}
-
-static void trim(struct chunk *self, size_t n)
-{
- size_t n1 = CHUNK_SIZE(self);
- struct chunk *next, *split;
-
- if (n >= n1 - DONTCARE) return;
- next = NEXT_CHUNK(self);
- split = (void *)((char *)self + n);
+ int i = bin_index(n1-n);
+ lock_bin(i);
- split->psize = n | C_INUSE;
- split->csize = n1-n | C_INUSE;
- next->psize = n1-n | C_INUSE;
- self->csize = n | C_INUSE;
+ bin_chunk(split, i);
- free(CHUNK_TO_MEM(split));
+ unlock_bin(i);
}
void *malloc(size_t n)
{
struct chunk *c;
int i, j;
+ uint64_t mask;
if (adjust_size(&n) < 0) return 0;
}
i = bin_index_up(n);
- for (;;) {
- uint64_t mask = mal.binmap & -(1ULL<<i);
- if (!mask) {
- c = expand_heap(n);
- if (!c) return 0;
- if (alloc_rev(c)) {
- struct chunk *x = c;
- c = PREV_CHUNK(c);
- NEXT_CHUNK(x)->psize = c->csize =
- x->csize + CHUNK_SIZE(c);
- }
- break;
+ if (i<63 && (mal.binmap & (1ULL<<i))) {
+ lock_bin(i);
+ c = mal.bins[i].head;
+ if (c != BIN_TO_CHUNK(i) && CHUNK_SIZE(c)-n <= DONTCARE) {
+ unbin(c, i);
+ unlock_bin(i);
+ return CHUNK_TO_MEM(c);
}
+ unlock_bin(i);
+ }
+ lock(mal.split_merge_lock);
+ for (mask = mal.binmap & -(1ULL<<i); mask; mask -= (mask&-mask)) {
j = first_set(mask);
lock_bin(j);
c = mal.bins[j].head;
if (c != BIN_TO_CHUNK(j)) {
- if (!pretrim(c, n, i, j)) unbin(c, j);
+ unbin(c, j);
unlock_bin(j);
break;
}
unlock_bin(j);
}
-
- /* Now patch up in case we over-allocated */
+ if (!mask) {
+ c = expand_heap(n);
+ if (!c) {
+ unlock(mal.split_merge_lock);
+ return 0;
+ }
+ }
trim(c, n);
-
+ unlock(mal.split_merge_lock);
return CHUNK_TO_MEM(c);
}
-void *__malloc0(size_t n)
+static size_t mal0_clear(char *p, size_t pagesz, size_t n)
{
+#ifdef __GNUC__
+ typedef uint64_t __attribute__((__may_alias__)) T;
+#else
+ typedef unsigned char T;
+#endif
+ char *pp = p + n;
+ size_t i = (uintptr_t)pp & (pagesz - 1);
+ for (;;) {
+ pp = memset(pp - i, 0, i);
+ if (pp - p < pagesz) return pp - p;
+ for (i = pagesz; i; i -= 2*sizeof(T), pp -= 2*sizeof(T))
+ if (((T *)pp)[-1] | ((T *)pp)[-2])
+ break;
+ }
+}
+
+void *calloc(size_t m, size_t n)
+{
+ if (n && m > (size_t)-1/n) {
+ errno = ENOMEM;
+ return 0;
+ }
+ n *= m;
void *p = malloc(n);
- if (p && !IS_MMAPPED(MEM_TO_CHUNK(p))) {
- size_t *z;
- n = (n + sizeof *z - 1)/sizeof *z;
- for (z=p; n; n--, z++) if (*z) *z=0;
+ if (!p) return p;
+ if (!__malloc_replaced) {
+ if (IS_MMAPPED(MEM_TO_CHUNK(p)))
+ return p;
+ if (n >= PAGE_SIZE)
+ n = mal0_clear(p, PAGE_SIZE, n);
}
- return p;
+ return memset(p, 0, n);
}
void *realloc(void *p, size_t n)
self = MEM_TO_CHUNK(p);
n1 = n0 = CHUNK_SIZE(self);
+ if (n<=n0 && n0-n<=DONTCARE) return p;
+
if (IS_MMAPPED(self)) {
size_t extra = self->psize;
char *base = (char *)self - extra;
size_t newlen = n + extra;
/* Crash on realloc of freed chunk */
if (extra & 1) a_crash();
- if (newlen < PAGE_SIZE && (new = malloc(n))) {
- memcpy(new, p, n-OVERHEAD);
- free(p);
- return new;
+ if (newlen < PAGE_SIZE && (new = malloc(n-OVERHEAD))) {
+ n0 = n;
+ goto copy_free_ret;
}
newlen = (newlen + PAGE_SIZE-1) & -PAGE_SIZE;
if (oldlen == newlen) return p;
/* Crash on corrupted footer (likely from buffer overflow) */
if (next->psize != self->csize) a_crash();
- /* Merge adjacent chunks if we need more space. This is not
- * a waste of time even if we fail to get enough space, because our
- * subsequent call to free would otherwise have to do the merge. */
- if (n > n1 && alloc_fwd(next)) {
- n1 += CHUNK_SIZE(next);
- next = NEXT_CHUNK(next);
- }
- /* FIXME: find what's wrong here and reenable it..? */
- if (0 && n > n1 && alloc_rev(self)) {
- self = PREV_CHUNK(self);
- n1 += CHUNK_SIZE(self);
- }
- self->csize = n1 | C_INUSE;
- next->psize = n1 | C_INUSE;
+ lock(mal.split_merge_lock);
- /* If we got enough space, split off the excess and return */
- if (n <= n1) {
- //memmove(CHUNK_TO_MEM(self), p, n0-OVERHEAD);
- trim(self, n);
- return CHUNK_TO_MEM(self);
+ size_t nsize = next->csize & C_INUSE ? 0 : CHUNK_SIZE(next);
+ if (n0+nsize >= n) {
+ int i = bin_index(nsize);
+ lock_bin(i);
+ if (!(next->csize & C_INUSE)) {
+ unbin(next, i);
+ unlock_bin(i);
+ next = NEXT_CHUNK(next);
+ self->csize = next->psize = n0+nsize | C_INUSE;
+ trim(self, n);
+ unlock(mal.split_merge_lock);
+ return CHUNK_TO_MEM(self);
+ }
+ unlock_bin(i);
}
+ unlock(mal.split_merge_lock);
copy_realloc:
/* As a last resort, allocate a new chunk and copy to it. */
new = malloc(n-OVERHEAD);
if (!new) return 0;
+copy_free_ret:
memcpy(new, p, n0-OVERHEAD);
free(CHUNK_TO_MEM(self));
return new;
}
-void free(void *p)
+void __bin_chunk(struct chunk *self)
{
- struct chunk *self, *next;
- size_t final_size, new_size, size;
- int reclaim=0;
- int i;
-
- if (!p) return;
-
- self = MEM_TO_CHUNK(p);
-
- if (IS_MMAPPED(self)) {
- size_t extra = self->psize;
- char *base = (char *)self - extra;
- size_t len = CHUNK_SIZE(self) + extra;
- /* Crash on double free */
- if (extra & 1) a_crash();
- __munmap(base, len);
- return;
- }
-
- final_size = new_size = CHUNK_SIZE(self);
- next = NEXT_CHUNK(self);
+ struct chunk *next = NEXT_CHUNK(self);
/* Crash on corrupted footer (likely from buffer overflow) */
if (next->psize != self->csize) a_crash();
- for (;;) {
- if (self->psize & next->csize & C_INUSE) {
- self->csize = final_size | C_INUSE;
- next->psize = final_size | C_INUSE;
- i = bin_index(final_size);
- lock_bin(i);
- lock(mal.free_lock);
- if (self->psize & next->csize & C_INUSE)
- break;
- unlock(mal.free_lock);
- unlock_bin(i);
- }
+ lock(mal.split_merge_lock);
- if (alloc_rev(self)) {
- self = PREV_CHUNK(self);
- size = CHUNK_SIZE(self);
- final_size += size;
- if (new_size+size > RECLAIM && (new_size+size^size) > size)
- reclaim = 1;
- }
+ size_t osize = CHUNK_SIZE(self), size = osize;
- if (alloc_fwd(next)) {
- size = CHUNK_SIZE(next);
- final_size += size;
- if (new_size+size > RECLAIM && (new_size+size^size) > size)
- reclaim = 1;
+ /* Since we hold split_merge_lock, only transition from free to
+ * in-use can race; in-use to free is impossible */
+ size_t psize = self->psize & C_INUSE ? 0 : CHUNK_PSIZE(self);
+ size_t nsize = next->csize & C_INUSE ? 0 : CHUNK_SIZE(next);
+
+ if (psize) {
+ int i = bin_index(psize);
+ lock_bin(i);
+ if (!(self->psize & C_INUSE)) {
+ struct chunk *prev = PREV_CHUNK(self);
+ unbin(prev, i);
+ self = prev;
+ size += psize;
+ }
+ unlock_bin(i);
+ }
+ if (nsize) {
+ int i = bin_index(nsize);
+ lock_bin(i);
+ if (!(next->csize & C_INUSE)) {
+ unbin(next, i);
next = NEXT_CHUNK(next);
+ size += nsize;
}
+ unlock_bin(i);
}
- if (!(mal.binmap & 1ULL<<i))
- a_or_64(&mal.binmap, 1ULL<<i);
-
- self->csize = final_size;
- next->psize = final_size;
- unlock(mal.free_lock);
+ int i = bin_index(size);
+ lock_bin(i);
- self->next = BIN_TO_CHUNK(i);
- self->prev = mal.bins[i].tail;
- self->next->prev = self;
- self->prev->next = self;
+ self->csize = size;
+ next->psize = size;
+ bin_chunk(self, i);
+ unlock(mal.split_merge_lock);
/* Replace middle of large chunks with fresh zero pages */
- if (reclaim) {
+ if (size > RECLAIM && (size^(size-osize)) > size-osize) {
uintptr_t a = (uintptr_t)self + SIZE_ALIGN+PAGE_SIZE-1 & -PAGE_SIZE;
uintptr_t b = (uintptr_t)next - SIZE_ALIGN & -PAGE_SIZE;
#if 1
unlock_bin(i);
}
+
+static void unmap_chunk(struct chunk *self)
+{
+ size_t extra = self->psize;
+ char *base = (char *)self - extra;
+ size_t len = CHUNK_SIZE(self) + extra;
+ /* Crash on double free */
+ if (extra & 1) a_crash();
+ __munmap(base, len);
+}
+
+void free(void *p)
+{
+ if (!p) return;
+
+ struct chunk *self = MEM_TO_CHUNK(p);
+
+ if (IS_MMAPPED(self))
+ unmap_chunk(self);
+ else
+ __bin_chunk(self);
+}
+
+void __malloc_donate(char *start, char *end)
+{
+ size_t align_start_up = (SIZE_ALIGN-1) & (-(uintptr_t)start - OVERHEAD);
+ size_t align_end_down = (SIZE_ALIGN-1) & (uintptr_t)end;
+
+ /* Getting past this condition ensures that the padding for alignment
+ * and header overhead will not overflow and will leave a nonzero
+ * multiple of SIZE_ALIGN bytes between start and end. */
+ if (end - start <= OVERHEAD + align_start_up + align_end_down)
+ return;
+ start += align_start_up + OVERHEAD;
+ end -= align_end_down;
+
+ struct chunk *c = MEM_TO_CHUNK(start), *n = MEM_TO_CHUNK(end);
+ c->psize = n->csize = C_INUSE;
+ c->csize = n->psize = C_INUSE | (end-start);
+ __bin_chunk(c);
+}
projects / musl / blobdiff